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Making Sense of the Data with Dr. Marco Altini
3.2k Plays1 day ago
Steve House sits down with Dr. Marco Altini — data scientist, physiologist, and founder of HRV4Training — for a deep-dive into one of the most misunderstood tools in endurance athletics: heart rate variability. With over 50 peer-reviewed papers to his name, Dr. Altini brings rare scientific rigor to a space crowded with oversimplified wearable metrics. The conversation opens by challenging the industry's obsession with single-number readiness scores, which Dr. Altini argues dilute nuanced physiological signals into deterministic assumptions that don't reflect the complexity of the human body.
The episode unpacks the fundamentals of HRV — what it actually measures, why morning is the optimal measurement window for endurance athletes, and how to interpret it as a marker of stress response rather than performance capacity. Steve and Marco also cover hardware accuracy across chest straps, optical sensors, and phone cameras; HRV research at altitude; and the broader question of how biometric data should support — not replace — the athlete's own sense of feel.
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Transcript
Understanding HRV Stability
00:00:00
Speaker
Stability is really what we are after when we look at HRV. For a very long time it has been pushed the idea that higher is better, more stable is better. It's not about HRV going up, it's about, you know, being within that normal range, which means that you stress the body and then it bounces back and when you measure again, it's again where it should be.
00:00:31
Speaker
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00:00:47
Speaker
It's a great way to get a feel for how we train our athletes for big mountain goals. Check it out at UppHillAthlete.com. That's UppHillAthlete.com slash L-E-T-S-G-O.
Introducing Dr. Marco Altini
00:01:01
Speaker
My guest today is a scientist who has arguably done more than anyone to move heart rate variability out of the lab and into the real world. Dr. Marco Altini holds a PhD in data science and has built a remarkable academic resume. He's a guest lecturer at Vrenje Universitet in Amsterdam, ah data scientist, an advisor for Aura, and has published over 50 peer-reviewed papers on physiology and health.
00:01:26
Speaker
He's also the founder of the HRV for Training platform. But the reason I wanted to speak to Marco was not so much his software, was more because of his philosophy. In a world where were wearables are trying to always sell you a green light or readiness score to run your life and your training, Marco has been a voice of restraint.
00:01:46
Speaker
He has been a data scientist who really understands how HRV works, telling us that if you wake up feeling gray, but your watch says you're tired, you should trust yourself, not the machine.
00:01:57
Speaker
He's also a serious athlete himself. He qualified for the Boston Marathon. He's done ultras. And he treats his own body like kind of a walking laboratory. In fact, I've been reading it along with his a substack where he spent the last few months strictly kind of manipulating his carbohydrate intake to see if he can force his own metabolism to be more flexible and burn more fat, proving that even for a genius data scientist, the hunger knock is still a real thing.
00:02:25
Speaker
Mark Altini, welcome to the Up Hell Athlete Podcast. Thank you. Thank you so much for having me, Steve. Real real pleasure to be here. Well, thank you. As I was saying before the show, you've had a lot of influence on us as a group of coaches. And i think that this like voice of reason has been a ah big reason for that.
Limitations of Wearable Readiness Scores
00:02:45
Speaker
And, you know, there, the, the wearables industry has been obsessed with this idea of a readiness score, a watch or device that tells you your body battery is 80% charged. And you've been pretty vocal that these aggregated scores can be very misleading and Can you help me understand why a single readiness number may or may not be scientifically flawed?
00:03:09
Speaker
Yeah, yeah, for sure. think ah there's um a topic that's been close to my heart for a while. um in in um I'll say that in principle,
00:03:24
Speaker
What they do, let's say the company is developing this course, kind of makes sense. Like, even if we, you know, it could come from a a positive approach even to their own story. Like, not trying to, you know, trick the user in any way, of course, but trying to help them. Yes. And, you know, it's ah it's a simple idea. Like, we have many signals. We aggregate them.
00:03:50
Speaker
And then you don't have to look at all the individual things. You don't need to be an expert in your sleep stages, in your HRV or resting heart rate, in your training behavior, in all sorts of things that are included in this core.
00:04:08
Speaker
And we just guide you this way. But I think eventually What happens is that this course do us a bit of a disservice because especially as athletes or people that are really interested in their training and now their body is responding to their training, right? Am I getting better?
00:04:28
Speaker
Am i capable of assimilating more stress today? Which is why we started developing these tools, right?
Analyzing Resting Physiology
00:04:35
Speaker
When we put everything together, we give maybe the false impression that we are providing more information, but we are actually, I think, diluting that information. For example, if I have a negative readiness score today,
00:04:53
Speaker
And that comes from my behavior, not my physiological response, because everything is together. And the model makes assumptions, right? There is this idea that is tracking you, is personalized to you.
00:05:08
Speaker
But in reality, there are broad generalizations and assumptions that are made for the score to exist, for example. do you do or did you do a lot more physical activity than you normally do, then you must be less ready. Your score must be lower. you must be less recovered. right It is a simple deterministic thing. It's not really about how you responded.
00:05:32
Speaker
It's just more exercise means less readiness. And similarly, less sleep means less readiness. But, you know, there obviously is a complex biological system. It's not so simple.
00:05:44
Speaker
Maybe you can take two, three nights with poor sleep. And of course, you don't want to make that chronic. So the behavior matters. But it does not mean that on those days you cannot perform or you cannot assimilate more stress.
00:05:57
Speaker
So I think eventually, especially as athletes, we might be interested in looking at our resting physiology.
HRV: Response vs. Performance Predictor
00:06:04
Speaker
As you said, you know, spent many years developing tools and looking at this data. I believe the data is useful, but I think it is more useful to look at the resting physiology data, resting heart rate, resting heart rate variability.
00:06:19
Speaker
in response to our behavior, so using behavior as context, more than, you know, aggregating having to get everything together and making, again, the assumption that you can determine what is the state of the body because we cannot do that.
00:06:33
Speaker
And I think that also has other implications because if we look at HRV, we could also talk to an athlete as a coach and explain what that it is and why we look at it.
00:06:44
Speaker
and also its limitations. While the idea of the recovery or readiness course is indeed that it puts everything together and as such, it is sort of no limitation, right?
00:06:56
Speaker
It's a comprehensive score of how you feel. But then we know, for example, that the main limiter for most athletes in endurance sports is probably on a given day, muscular soreness, right? If we did a hard session yesterday,
00:07:14
Speaker
that we might be sore and unable to do another one today, even if our resting physiology is perfectly normal. And those kind of things, for example, from the muscular point of view, cannot be captured by any of these technologies that are available today is to use.
00:07:31
Speaker
So it's just something that is part of the equation. And as a coach or as an athlete, you need to keep in mind, of course, and that's why we periodize training and plan, you know, hard days, easy days. Obviously, there's that component is always present in our mind, but it's not tracked by the device.
00:07:49
Speaker
So I think, again, the comp compound score, the readiness recovery score, hides also these limitations of the technology and the people expect that those things can also be tracked but they cannot so I think we are just better off you know breaking it down again and looking at the individual components and looking at the objective data and then looking at the behavior and then of course there's always the subjective component that in my view and I guess also your view is one of the key components
00:08:22
Speaker
But that doesn't fit the rhetoric of the tool automates everything and you don't have to do anything. So you don't even, you know, fill in a questionnaire or anything like that before getting the score. Because like the score knows your body better than you, which of course is not the case.
00:08:39
Speaker
So what I'm hearing you say too is that, and and we've been talking about readiness score, and we're also going to talk about heart rate variability and they're they're related, but they're they're
Optimal HRV Measurement Times
00:08:50
Speaker
two different things. we want to clarify that.
00:08:52
Speaker
So let's let's dial in a little more tightly on HRV. Why is HRV a response to stress more than a predictor of performance? And can you kind of unpack that? I think that this is kind of one of the core misunderstandings of heart variability and Can you help us understand how that works?
00:09:15
Speaker
Yeah, yeah. So hardware viability, if we measure it at the right time, which I think is important because at the beginning this was taken for granted, but right now there's tools that measure it all the time and extrapolate what could be done at a certain times to, you know, 24-7. And also that relationship doesn't really exist and the tool cannot be used that way.
00:09:37
Speaker
But let's say we measure at the right time and that typically means... So we pause there. What is the right time? I gotta know. Yeah, so the right time, i would say either first thing in the morning or with some different considerations throughout the night.
00:09:55
Speaker
So the way wearables do it automatically as you sleep, I think is also fine. What differs there is that, of course, you measure earlier while in the morning you measure after the restorative effect of sleep. So in my opinion, it is a better time for that reason, because okay you meant You give more time to the body to the recover from the stressors of the previous day.
00:10:18
Speaker
And also you include the sleep as a positive if the sleep went well stressor or otherwise if disrupted or or anything like that. You still capture your data first thing in the morning after that.
00:10:32
Speaker
And also measuring in the morning allows you to measure in a different body position, which I think also is key, especially for endurance athletes. So to measure when you're sitting up, the body is slightly more stressed, so to speak. And that makes the measurement more sensitive to stress. So changes that while you are sleeping are very small.
00:10:52
Speaker
That typically are the changes due to training and even going at altitude and things like that. So sometimes it's more subtle changes, especially for good athletes. And if you sit up and then measure shortly after, let's say within a minute, those changes are amplified. So then the measurement becomes more useful because you see these things better.
00:11:13
Speaker
While the night measurements, you know, you will certainly see if you're sick. But that's, you know, an enormous stressor that hopefully you're not facing very frequently, right? So if you want to really balance training and things and things like that, then again, the morning might be a better time. So let's say we measure HIV at those times.
HRV's Role in Training Decisions
00:11:33
Speaker
What the data reflects is our capacity to assimilate stress, in that moment, let's say, so for the day ahead as we plan training.
00:11:45
Speaker
And not necessarily our capacity to actually perform. so And that is indeed a common misconception, like in the past especially, i think a lot of people thought with a low HRV, low typically means higher stress, right? So it's a negative thing. So with a low HRV, you would have trouble executing the training.
00:12:07
Speaker
but That is not really the case. We've seen these quite a few studies. Also, typically in the world of, let's say, HRV-guided training, which means that, you know, you have two groups of people. One is doing some form of periodization and the other group is doing the same.
00:12:25
Speaker
But then the periodization is slightly adjusted on a day-to-day basis, depending on the HRV data. So that's why it's HRV-guided. So what you see eventually is that it's not as much about what you can do, but it's about how much you can assimilate of the workout to get better over time, which is the goal of training.
00:12:50
Speaker
So if you have a low HIV on race day, it doesn't matter because you're racing, right? Then you will take, you know, time to recover and so on. But then during a training block, it seems favorable to not add stress on a body that is already stressed because then we can execute the training, but then we will not get better. So it's sort of useless to do it.
00:13:14
Speaker
And yeah even there, I think it's important to um understand that the data reflects many different things because HRV is just a marker of stress, of our stress response.
00:13:29
Speaker
And, you know, it could be just the evening before you ate something that, you know, didn't go well with you and you have a bit of suppression. There's nothing to worry about. So I don't think we need to be very reactive. Like every suppression, we need to change the training and things like that. And also research has reflected that. Like in the past, that was the approach.
00:13:51
Speaker
Well, now typically you look at the moving average, so a week basically of data with respect to what is considered your normal, and your normal is typically built over one to two months, so it's a broader range.
00:14:04
Speaker
And if your weekly average goes below your normal, then a change is implemented. But of course, for a weekly object to go below your normal, it takes a couple of bad days. So you're not reacting to any change. But then if you do have a couple of bad days, then maybe it's a good idea to make a small adjustments and wait, you know, so that things re-normalize before you add additional of stress. So I think that is a bit the principle behind it and how it is used today.
00:14:33
Speaker
And I mean, that's the principle behind coaching. I mean, there's so many, you know, times I've told people I can give, you know, 20 athletes the same workout and it's all going to, it's going to have a different effect on each of them. And, and that's what we do as coaches every day is, you know, look at the athlete in the morning, get the kind of subjective report, look at the, look at the data and then say, okay, yeah, I think you can absorb this much stress today or that much stress today. talking about training stress here. um But I mean, the other stresses of life are all also relevant, right? Like you need to be aware of. And HRV is trying to ah pick up on all of those. And and then, you know, the the modeling you're doing is trying to say, okay, this is how this relates to how we up or down regulate the training stimulus. And I think that that's that's that's exactly the way a coach's mind works. And I think that that's really one of the strengths of this.
00:15:30
Speaker
approach is that it is trying to replicate a human knowledge worker process, if you will, um, to try to like pull on all the collect all the data.
00:15:45
Speaker
look at the plan, make an adjustment to the plan and, and look at this sort of over, not just days, but weeks and months and and years. So that's, that's sort of, sort of interesting. So what's the bottom, like, what's, what do you tell people that they say, my my data, HRV says I'm a red light, but I feel like a green light, you know, who's right.
00:16:06
Speaker
How do how do you, and how do you have that conversation with an athlete? Yeah, so um I think I've gained a lot more experience in this in the past two years since I've started also coaching endurance athletes. And I see that often the question is, my data shows this.
00:16:25
Speaker
And the other the part that you mentioned, like, but I feel like this, it's not even there. So it's, you know, it's the data shows this. And then my first question is always, how do you feel, right? So that is, I think, the most important piece of information that on time is not even apparent, right? Because, of course, if you just look at the tool, the tool doesn't know, but then the objective data doesn't know, but you need to talk to the test, right? You need to get that sort of input. So...
00:16:53
Speaker
Typically, I think the people that work with me, I'm obviously lucky that they have read about the things I wrote. So a lot of the explaining has already been done in the v blog and and it becomes easier. But I try to stress these points that we discussed. So the fact that, you know, a low day can happen because of many different things.
00:17:16
Speaker
and it does not impact our ability to perform the session. At the same time, we don't want to get in a situation of chronic negative response to stress.
00:17:27
Speaker
So how do you feel? The most important thing, because if you feel poorly, then the data is just reflecting something that is off. Maybe you're really getting sick or something like that. So in that case, we might take action, right?
00:17:41
Speaker
But if you feel good, typically say, hey, if you feel good, we do the session and we see what happens. Meaning that typically if it was nothing the day after, everything is normal. And then it means that, you know, there was no need to make changes. So I always give it two or three days if the person feels good and we see if everything renormalizes, which happens basically every time, unless, you know, there is really something stronger happening. And of course, sometimes can happen, but it is again,
00:18:10
Speaker
ah rare if the person also feels good you know for two or three days, it's difficult that you develop something negative. um And then, yeah, so we I start from there, from that question, and then we try not to be overly reactive and really use the data in certain situations in which then we have a couple of bad days. And typically,
00:18:30
Speaker
I would say maybe every single time is life happening more than training, right? So I think that's where the data is useful, even though many people say okay, when I want use this tool to really guide my training.
00:18:46
Speaker
But what the tool ah does, so what NHLV measurement reflects is just overall stress. And training is typically, I plan it in a way that, you know, should not end up, you know, in a hole, right? So there's, um stress is applied in a way in which I think is what you can handle right now, depending on your history and and everything in your life, right? So it's very unlikely that we do some sessions and we see that, you but reduction in HIV after the session. Typically, I would think that there we did something that maybe you we're not ready to handle. So again, unlikely to happen.
00:19:25
Speaker
But then, you know, people travel or their kids are getting sick or there's, you know, all sorts of, you know, seasonal allergies, like all kinds of sort things, right? Exactly.
00:19:36
Speaker
So we are all exposed to all sorts of stressors all the time. And that's why the data is useful, I think, because it gives us context also in terms of all these things that are happening and where we might not really be aware sometimes as coaches even if we talk to our athletes you know so much happens in everybody's life that if we see something maybe it's just an excuse to start the conversation right it's like hey The data's been low two days. What do you think is up? And maybe you know they tell me, hey, yes, my family has been sick for a week. I'm like, ah okay, so maybe we need to think about that. there is Yeah, yeah, exactly. And it's not always so straightforward, but in general, I think that's a good way to go about it. So you look at the data, you have a conversation, and you see what other stressors are present and try not to be overly reactive, but then still
00:20:28
Speaker
Pay attention here and there to also make sure we don't get, you know, the situation in which we are always in a negative physiological response, so to speak, which is unlikely to help us long term.
Understanding HRV and Autonomic Activity
00:20:41
Speaker
Maybe we should have done this earlier, but can you explain to me in the audience what exactly HRV is measuring and how it does it? Yeah, for sure. So when we measure HRV, we look at the variability between heartbeats because the heart does not beat at a constant frequency. There is always some variation, and this variation is not random, but it's actually due, again, when measured at the right time, so in the morning, during in the night, it is due um to the activity of the autonomic nervous system.
00:21:16
Speaker
And the nervous system is basically modulating heart rhythm and therefore heart rate and heart rate variability in response to stress.
00:21:27
Speaker
So we face a stressor, again, any stressor as we just mentioned. And then we have a physiological response, like from a hormonal point of view as well, right? So our cortisol might rise and there's all sorts of things that are happening that we cannot easily measure.
00:21:43
Speaker
So it's not that it's less relevant to look at hormones with respect to heart rate viability. It's just that it's not easy. While the response of the nervous system, and in particular the parasympathetic branch, the one that is more active in a state of rest and relaxation, impacts heart rhythm, so makes variability higher when there is higher parasympathetic activity. So a higher recovery or rest state typically makes variability a bit higher, and the stress makes it lower, while heart rate is the opposite, right? I think
00:22:17
Speaker
To that, people can easily relate when they are stressed, they feel their heart is racing, and you know, that is actually happening, heart rate is higher, and variability is reduced. So all of that is driven by the nervous system, and when we take this heart rate variability measurement, in practice, it's just an an indirect measure of our stress response.
00:22:37
Speaker
I think there also the key again is really is the response, right? It's not the stress per se. So if we respond well to stress, then our variability will be back to normal after maybe maybe an acute suppression that is normal. But again, we measure, you know, 24 hours later in the morning or in the night.
00:22:56
Speaker
Everything is re-normalized again after our training or all other stressors because we responded well even if there was high stress. So good viability doesn't mean no stress, it means good response.
00:23:09
Speaker
And then if we cannot re-normalize within 24 hours, typically something is off. And what is it, how does it actually physically, the measurement made? I mean, we all think of in the old days when people would put the probes on the, on the chest, um, like an EKG type machine, now it's done in a ring or with the phone camera or a, a, a, some sort of device, a whoop band.
00:23:37
Speaker
to How is that working and how direct is that measurement? Yeah, that's also a great question because in reality, heart rate variability is the variability of heart rhythm and that can only be measured with an electrocardiogram. So right now, the most easy to use electrocardiogram is not anymore, zel electrodes and things like that, but it still is a chest strap, right? So like a polar chest strap works great for a heart rate variability analysis. So you would put that on and take your measure measurement in the morning.
00:24:09
Speaker
Then, of course, this is also sometimes not the most convenient way, or at least since the development of optical technology, like what you have in the rings, in the watches, or in our app with the phone camera.
00:24:21
Speaker
That means that you are looking at change at the periphery. So again, not at the heart, but you're looking at blood volume changes, for example, at the finger, because of course the heart beats and blood flows. So at the periphery, you can look at changes.
00:24:38
Speaker
This is typically very highly correlated, which means that on a day-to-day basis for a person, the data follows basically the same trend when you measure it in two different places.
00:24:51
Speaker
There can be small differences because, of course, by the time it reaches the periphery, there's other factors that impact. blood flow like blood pressure, for example. So um there can be variations and there's also so for some people there could be larger variation than for other people.
00:25:10
Speaker
But in general, I think it's accepted that these methods can be very accurate, especially to capture relative changes over time. assuming you know again the device is being validated against tcg like it's not that all optical sensors can do that but even the chest traps like not all chest traps can measure heart rate variability correctly like i have a bunch here because you know for work test things and so on but when i measure i always use the polar one because i see that with the other ones the data sometimes is more erratic so even if they can give you heart rate correctly
00:25:41
Speaker
does not mean it can give you heart rate variability correctly. So um so it's always important to use a device that at least has shown in some validation published that um it's very close to an ECG, you know.
00:25:55
Speaker
Interesting. Yeah, I've personally and with my athletes experimented with the with the chest strap and that was very intuitive to me how that could, i think I was using a garment at the time i i was trying it with the actual chest strap.
00:26:11
Speaker
But from i've I've wondered what that correlation is, and I haven't personally seen that that data or those validations. And then, you know, I knew that, you know, your app uses a ah phone camera. I know that there's, you know sort of based on the same optical technology that would be in like an aura ring or, and I assume that Whoop works the the same way. um and i And I was never that confident in them. Is there a significant variation in the accuracy of the different optical methods that are measuring in the extremities or are they all similar or the same?
Accuracy of Optical HRV Measurements
00:26:49
Speaker
so I would say they are very similar at the end of the day when you are asleep or when you take a measurement that is short, like with a phone camera in the morning. Because ah in a situation in which there is very limited movement, because in theory, let's say, the finger is a better place, right? That's because, you know, you have closer access to the arteries, while in the wrist, the arteries are actually at the bottom and the sensor typically is at the top.
00:27:15
Speaker
And we all know from you know exercising and running that wrist heart rate is typically the worst place where you can measure it. And now you have even the same technology you know in arm bands that you place you know just maybe near the shoulder and just day and night. right It works so much better. It's the same thing.
00:27:33
Speaker
So it's just the wrist is just a poor place to measure these kind of things. But when you sleep, that's different, right? You're not moving, there's almost no artifacts. So even there, I think it's good.
00:27:45
Speaker
So in general, um I would say these technologies can be used. um At the same time, also with our app, like with the camera, The latest iPhones, for example, they put the flash and the camera very far.
00:28:00
Speaker
And that is a problem. like To the point that myself, like since the new phones, I used the strap again. right Because I used the camera for you know a decade. Always worked great.
00:28:11
Speaker
But then the technology was... So the phone, let's say, could be hacked the correct way. Because the the camera and the flash were next to each other. And you need to... use the flash to again illuminate the finger so that you can record the change in blood volume. But if the flash is very far, then you cannot do that well. So for me, it was a simple matter of using the strap.
00:28:33
Speaker
But then, you know, it's just to highlight that it's never so simple or it's never the same. Technology evolves and things like that. And with wearables, also the same. Like, They decide the design, but at the same time, there's many considerations beyond HRV in what they are doing. And then there is a new generation of hardware, and maybe there is more sensors, and maybe the HRV piece becomes something, you know, that again has trade-offs with respect to the new things that they mounted in there that they want to do.
00:29:01
Speaker
So everything needs to be validated, sort of every iteration, just to make sure we still collect good data. Yeah, interesting. I want to ask you about the orthostatic stress and I'll just tell you a little story. Like when I was training full time 20 years ago and there's a sort of professional athlete climber, we used orthostatic tests for our recovery, you know, like do like,
00:29:27
Speaker
box step ups, for for example, get the heart rate up to a certain amount and then sit in always the same kind of position and measure how quickly the heart rate came down. and we used to use this also like on on expeditions at Basecamp. It was sort of this incredible, portable, low tech way to measure recovery. And I felt like it it worked pretty good. Again, gave another data point. It felt more more objective than just pure feeling. Um, and it often aligned with, with pure feeling. So talk, can you talk to me about orthostatic stress and why body position matters when you, when you, when you, I mean, we've talked about the, the time of day, but the position of the body and that it's, um, I guess similar between tests is, is important or is relevant, right?
Enhancing HRV Sensitivity with Orthostatic Stress
00:30:20
Speaker
Yeah, yeah, it's very important that we measure in the same position and even that if we can, we exploit really the orthostatic stressor, like basically the change in body position, right? So the test you were doing and then looking at heart rate is, I think, is great. Now with HRV, I think the advantage is that it's a more sensitive measure of stress.
00:30:42
Speaker
So we don't need to do so much to see a change like we would do with heart rate and where maybe we were looking at, again, the heart rate recovery and things like that.
00:30:53
Speaker
So typically at rest with HIV, we can capture much of that change. But... If we change body position, then of course we create, basically, you know, the body has to respond to that change, right? Even just in terms of blood volume and, you know, pulling in the right places and things like that because you don't want to faint every time you stand up, for example, right? So yeah those kind of changes...
00:31:17
Speaker
make it so that if you measure shortly after, then the measurement is just more sensitive to stress because the response is amplified. So if I'm a bit sick and, you know, not badly sick, just a bit sick, and then in the night I'm still sleeping, having a decent night, and maybe my heart rate instead of, you know, 48 is 50, that change is so small that I cannot really see much into that. It's just day-to-day variability is within that.
00:31:45
Speaker
But then if I sit up in the morning, then instead of being 51, it's 63. it's sixty three like The change is really amplified by that change in body position on the same day. like And I have collected also this type of data like to show the importance of the orthostatic test and changing body position and so on.
00:32:05
Speaker
So that's why I'm saying it's a good... thing to do. It's simple. If you're already taking your morning measurement, just do it sitting up. And then typically the data is a bit more useful.
00:32:16
Speaker
And that is all there is, I think, in terms of the orthostatic stressor because HRV is more sensitive than heart rate already. So we don't need, you know, to do maybe a measurement before changing position, a measurement after that was also done in the past, or maybe a more complex test, a bit like you were doing as well. i think we can still keep it simple with a resting measurement, but after the change in body position. I think that is um a better protocol. There was actually a study very recently, maybe last year, ah with people going at altitude. And you could not see a change even going at altitude in their night data. So night HIV was the same.
00:32:55
Speaker
But then they measured also in the morning standing up And it was a huge change with respect to sea level. So it's just easier to capture it that way. And then I would assume, you know, if you keep measuring and you stay at altitude and you adapt,
00:33:07
Speaker
then, you know, that difference with sea level would narrow down, while, again, in night data it would always be the same. So, you know, sometimes it's very convenient to use wearables, but it doesn't mean that Charcollet can use wooded.
00:33:20
Speaker
Yeah. I want to come back to altitude in a little bit, because I think that's going to be super interesting for our audience, but I want to kind of drill into people that HRV reflects a response to stress, not how hard you trained and it's more, how did you respond to the training and it you know, that's, that's something that I re a concept that I am constantly explaining to athletes.
HRV Suppression and Stress Absorption
00:33:47
Speaker
That is, I think counterintuitive when people haven't been training much before that they think, you know, watch too many Rocky films and, and seen too much of this like a macho version of, of training and.
00:34:02
Speaker
real training is much more subtle and much more about signal and response. Um, and I think HRV is, is, is aligned with that. It's a response to the stress. Is that, would you amend or edit anything in that statement? You know, I think that's great. It reminds me actually of how some people think that when they train or train hard, they should see a suppression in HRV the day after. Like if they don't, they think they didn't train hard enough.
00:34:32
Speaker
But that is absolutely incorrect. Like if you see a suppression, you just went way beyond your capacity to simulate that stimulus. And that means typically that, you know, it's not going to it's not going to help you get better.
00:34:46
Speaker
And in fact, like the best athletes, you know, elite athletes that... definitely train a lot, high volume and very hard, have the most stable data. Like there is very, very few suppressions and it's hardly ever about training. Again, maybe it's travel if they are competing somewhere else or again, all sorts of things that happen in everybody's life. But The response to training, actually, the better you are, the fitter you are, the quicker you rebound to your normal, right?
00:35:19
Speaker
Which is also why, as a good athlete, you can take more training or maybe you can train twice per day. It's just you're not training in that depleted state or in that overly stressed state or before you bounce back through to normal, to homostasis. It's like you just bounce back very fast.
00:35:34
Speaker
and so typically even if you're training very hard and the day after your hiv is normal that is a very good signal it means you know you could take that training you're absorbing the training well yeah i think that that's that's absolutely right and you know we've yeah 100 agree with that i want to we you know so when we've talked about stress and hrv the illness has come up a a bunch of times In some of the writing that I've read of yours, you've been very precise about the differences between detecting not predicting illness.
00:36:10
Speaker
Can you explain that to us a little bit? Yeah, I think that was part of peak hype, HRV, during the pandemic or those times where, you know, like tools tracking HRV and, you know, there was always this statement meant that HRV would predict illness. I mean,
00:36:35
Speaker
For sure, there are situations in which your body is already sick and you haven't developed symptoms yet. So you have not noticed yet. So there is a case for the data sort of showing something that you have not realized yet, even though, of course, that is something that is already happening in your body. It's not that you know we're pre predicting the future, right because then sometimes that's really what people think. So we
00:37:08
Speaker
we maybe have not developed symptoms yet and you might already see it in the data to certain next extent. Even though I think most, in under most circumstances, typically the data is simply reflecting what we also feel like we feel down, you are getting sick and you also see it in the data like the two come together. It's not very different from training. um So I think in general,
00:37:36
Speaker
Maybe for some people it helps them pay attention a bit more or some cases in which you are a bit more uncertain about you know how you feel. That is also the use in training again for objective data is As you also mentioned during your expeditions as an athlete, you do the test to have one extra data point because even when you're in in tune with your body and you know feel is what drives your decisions, still it's not black and white every day. So sometimes you're pushing your limit and you know you' just have another data point to consider.
00:38:12
Speaker
So think in that context it can be useful. But, you know, the data typically can only reflect what is already happening in the body. So it could also be that if you pay attention a little more, you realize you already have some symptoms that maybe you were ignoring.
00:38:25
Speaker
Yeah, 100%. higher percent I love that distinction. And i' want to go back to connect back to what we said we were talking about a minute ago with how as athletes get fitter, their suppressions are less.
HRV, Fitness, and Misconceptions
00:38:39
Speaker
And people, I've had athletes that expect their HRV to climb as their fitness improves. But that's usually not what happens. And I think we need to understand this idea of parasympathetic saturation to explain why super fit people, sometimes their HRV just sort of looks stagnant.
00:38:59
Speaker
And another you know variable that that I learned about from from reading your work is a coefficient of variation as ah as another metric. can you kind of put these, I mean, we're going to get to some sort of technical terrain here, but I know there's a big chunk of our audience loves this stuff. So let's, can you help define these terms that, that crop up and how to help us see what. Yeah. Yeah, for sure.
00:39:26
Speaker
So in terms of. our absolute HRV, so the value of our HRV, you know, not related to how it changes over time with respect to our history, but just the number.
00:39:40
Speaker
think maybe we can start there because there also there's some misconceptions about, you know, higher values always being better or better athletes having higher HRVs.
00:39:51
Speaker
So I think none of that is true. So, higher values, abnormally high for you. So again, you have a normal range like you have for your, you know, for blood glucose or blood pressure, there's also for HRV, but unlike blood glucose and blood pressure, yeah the normal range is not population-derived, it's actually only your own.
00:40:15
Speaker
And that is because the genetic component of HRV is maybe predominant even in terms of this absolute value. So it wouldn't make sense even if I take, you know, I'm a male and I am 42 years old, even if I take only people like me and that even train like me or, you know, and are from this area of the world and so on, still the HRV would be all over the place to the point that I cannot build a frame of reference for my own data using even people like me.
00:40:45
Speaker
So the only way to have a frame of reference is to collect my own data for, let's say, a month, ideally two, and then we build this normal range. Now, when your data is above this normal range, so that's particularly high, abnormally high,
00:41:00
Speaker
That could be also that the body is in a state in which is not very recovered, so to speak, but is working hard to recover. So maybe it's too parasympathetic in a way.
00:41:13
Speaker
And typically that comes also with heart rate quite suppressed. And I think people that coach or train are familiar with heart rate being suppressed during a run, for example.
00:41:23
Speaker
That, you know, it's not a sign that you suddenly got extremely fit, right? It's typically sign that you're fatigued. so yeah Yeah, you can't get your heart rate up as yeah like you expected. And athletes ask us all the time, like, why couldn't I get my heart rate up yesterday? And the answer is when they don't like to hear us. So they're probably too fatigued for that workload. Yeah, exactly. So for resting physiology, we can think similarly sometimes. So if there is an acute change where heart rate is quite suppressed and HIV is quite high, then it could be that, you know, again, it does not
00:41:57
Speaker
It cannot be interpreted as many wearables do, which is higher is better. So go out and go very hard. So that is another misconception I think is important to remember. It's much better to be within your normal range than to be with particularly high value, because that could mean, again, there is just more fatigue.
00:42:15
Speaker
So that is one side of things. And given that there is a strong genetic component, again, you might be a very good athlete and your heart rate, typically resting heart rate, tends to be quite low. So there is a much stronger link between your cardiorespiratory fitness and resting heart rate than there is with HRB.
00:42:36
Speaker
So your HRV could still be, with respect to the population, not particularly high. And, you know, you would use the data in the same way. Relative changes with respect to your normal, how that goes.
00:42:47
Speaker
But it's not that you need to have particularly high values. So I think that's just important to know because people expect maybe that, you know, the HRV should be higher for fitter people or that as they get fitter, it gets higher.
00:43:00
Speaker
i think i think much of the change in HRV as they get fitter, If they were beginners before, maybe so there is a bra dramatic change in fitness, then there can be some change in HRV, but that's typically also just a reflection of the fact that the resting heart rate is going to be lower.
00:43:14
Speaker
So there is more room for variability. So it is kind of accounted in large part by the change in heart rate. Now, the issue of parasympathetic saturation that you mentioned, I think is something also to keep in mind um in certain situations. So what that what does that mean? So parasympathetic situation means that basically HIV
00:43:39
Speaker
under certain circumstances, does not track parasympathetic activity anymore very well. Because even if parasympathetic activity increases, basically the receptors in the heart are saturated, meaning, you know, they cannot take anymore.
00:43:58
Speaker
It's like, you know, you have a glass of water and then if the water level never reaches the top, then, you know, it tracks very well, but then if you reach the top, you can keep putting water, but it stays there. You cannot measure more water in glass. You cannot measure more than the size of the vessel. So it's the same in this case.
00:44:19
Speaker
And also there, i think, typically, we've seen that if you get people to measure while sitting or standing, you sort of remove this problem, meaning that it is more unlikely to show to see saturation.
00:44:33
Speaker
Again, if you use the orthostatic stressor to change position, so basically you stress a bit the body. Typically, of course, the HRV data, for example, even in absolute numbers, tends to be a bit lower and when you're sitting or standing with respect to lying down.
00:44:46
Speaker
And so that is a simple trick, but maybe in IDATA it's not possible to do that. And so it there could be a situation in which HIV does not change much, and that could be a good saturation. It's not really something as diagnosis. You cannot look at and see you know if heart rate is you know not changing with respect to the neurotransmitters that are modulating heart rhythm. So it's a bit of a sort of...
00:45:13
Speaker
Empiric way to to look at things. Is your heart rate very low? Are your training at a very high volume? Are you measuring early in the night? Are we not seeing changes? Then it might be so weird. or Now, the other thing you mentioned was the coefficient of variation.
00:45:29
Speaker
This is a bit of a different way to look at the data. Instead of looking at your weekly average or your daily scores, you look at how much your data is changing over a period of time, typically a week. So how much jumping around you have in a week.
00:45:48
Speaker
Because if your HRV is 100 milliseconds, the average of this week, obviously it could be that every day it was 100, or it could be that it was, you know, 120, 80, and so on, right? So it jumps around more.
00:46:01
Speaker
This variability, invariability, right, so how much it jumps around, is also reflective of your stress response. in a way that typically if your HIV is within your normal range or let's it's good, it's not particularly suppressed, then it is but preferable for the coefficient of variation to be low, which means the data to jump around less.
00:46:27
Speaker
Because, again, it's also quite intuitive, right? if it is If you are training or there is another stressor and today is very suppressed, right? And then you recover tomorrow, you you know take an extra nap and you know you eat well and so on and then you jump back up.
00:46:40
Speaker
And then you are again very stressed and again is suppressed. So there's a lot of jumping around to be like not a great thing. And there is also individuals, so it's not that for every person it's the same amount of jumping around.
00:46:53
Speaker
And that is also something keeping mal never compared, you know, with your friends' day-to-day variability. It's about how it's changing for you with respect to your historical data.
00:47:04
Speaker
Is stability more important than magnitude in that sense? Or am I misunderstanding Yeah, I think stability is really what we are after when we look at HIV. And for a very long time, it has been pushed the idea that higher is better. And I think we are finally getting to, you know, more stable is better. It's not about HIV going up.
00:47:29
Speaker
It's about, you know, being within that normal range, which means that you stress the body and then it bounces back. And when you measure again, it's again where it should be. So the stability of it, I think, is the optimal response more than an increase or anything else.
00:47:45
Speaker
And the stability as it relates to you and based on, and you kind of specify like a range of sort of, you know, six to six to eight weeks, or what what did you say? Six to eight weeks or four to eight weeks of data to kind of establish that?
00:48:01
Speaker
Yeah, yeah, exactly. So in our app, we use two months. And in research, typically they are in a rush, so they use one month. But I think, you know, anything between one and two months is acceptable. yeah The one thing I wanted to kind of ask you is if this, and I'm asking for a friend, had this happen where someone, their sleep is good, their nutrition is good, their stress is low, and the HRV is still trending down.
00:48:30
Speaker
Is that in that case still an early overtraining signal or, you know, and assuming this is relative to that person. Yes. Is that, is that what it most likely means?
00:48:43
Speaker
And how do we know that that's the correlation? yeah Yeah, not necessarily, maybe. um What I mean is that, first of all, I think when we use this data, while useful, we also need to accept that we don't have all the answers. And sometimes there might be changes that we don't know exactly what is happening.
00:49:03
Speaker
But the one thing that we should keep in mind always um which of course you are very well aware of given, you know, all the work at Altitude and so on, is that our environment.
00:49:16
Speaker
But our environment sometimes means even just the seasons changing. So there's seasonality in our physiology. And I think that is something that we also need to keep in mind because because typically if we live in a place where seasons are quite different in terms of how long is the day, the temperature, and you know again, um yeah, just I would say mostly these daylights and temperatures, then those factors reflect in our resting physiology quite well. There's also studies showing studies showing this where basically your resting heart rate tends to be lower in summer and higher in winter. And HIV is the other way around, so it's a bit lower in winter and higher in summer.
00:50:06
Speaker
So, you know, if you see some changes that you cannot explain very well and are also quite chronic in a way, so it's not that it is suppressed a day or two, but it kind of stays there for a week or two.
00:50:20
Speaker
It could be also these kind of changes in our environment or the seasons and, you know, depending on where we live and so on. So sometimes it's kind of it's kind of like, you know, that's how it is. It's not really that if you cannot change your environment, then then that's how it is. and What are the implications for training? I think maybe that's an open question. Like, I don't think we know that. Like, sure, there is a change in our physiology and maybe that means that we really cannot assimilate the same amount of stress that we could assimilate, you know, over summer.
00:50:53
Speaker
Maybe that is the case. Training certainly differs typically for people living in this
HRV and Menstrual Cycle Effects
00:50:58
Speaker
environment. So, you know, the racing season is summer typically in the mountains, right? And then... in In winter, there's a lot of base training maybe and different kind of like less intensity or smaller bits of intensity. it depends, of course.
00:51:13
Speaker
But still, it could be at that something there is also driven by these changes and not necessarily something as but related to training or negative in the response of the person.
00:51:25
Speaker
um yeah I would say, again, we don't always have an answer, but we also need to keep in mind that it's not only the factors that we can control, it's also where we are placed as people and and how that impacts us Interesting.
00:51:42
Speaker
Yeah. Okay. Well, that, that bridges to one of the other kind of seasonalities I wanted to ask you about. um ah Half of our athletes are female and ah a lot of them flagged as stressed for 10 days a month simply because of their, in the luteal phase of their cycle.
00:51:59
Speaker
Physiologically, what happens to HRV during this phase of a woman's cycle? And as a coach or as an athlete, how should I think about adjusting their baseline so we we're not giving them false rest days based on that feedback?
00:52:15
Speaker
Yeah. So I think there. So I'll tell you first what at the population level can be seen in the data. But then we talk about the m individual well because that changes everything that would be the advice, for example.
00:52:31
Speaker
So at the let's say that that very broad broadly speaking at the population level, we see that the physiology in terms of resting cart rate and HRV tracks similarly to changes that we see also in temperature, which is of course due to hormonal changes during the cycle. So in the second phase of the cycle, the luteal phase, typically there is a reduced HRV and slightly a higher heart rate, and that is what we can see at the population level.
00:53:00
Speaker
But then i think, just like in many other things, physiology and training related, the individual variability is higher than the variability between groups, even groups of similar people.
00:53:14
Speaker
So the individual variability is so high that between two people that have the menstrual cycle, we could have very different ah responses in the resting physiology data.
00:53:28
Speaker
But even the same person across cycles all the time can see different patterns because the symptoms might be fair bit different. The other stressors that are present are of course different. We are not, you know, static. And, you know, again, the seasons are changing. Our training is changing. Our other stressors are changing. So everything changes at the same time.
00:53:54
Speaker
So it's very difficult, I think, to have expectations on the data or to see in the data what we see at the population level. And then there was a study it's just, I think, out this week also looking again at HLV and other parameters in different phases of the cycle, but then looking also at performance outcomes in athletes.
00:54:18
Speaker
And so they could show that in different phases, that the physiology was different, again, as we discuss now, but then the performance was not.
00:54:31
Speaker
So, again, the the change in physiology doesn't necessarily mean that the athlete will perform differently, better or worse. Like, they could perform the same in the different phases.
00:54:43
Speaker
So I think that is also important to know because the person might have symptoms and of course those need to be accounted. But at the same time, we you can never be sure that you know you' are in a certain phase and the athlete feels good, like performance might be as good.
00:55:00
Speaker
It's not necessarily worse, so to speak, because in that phase we know that typically HRV is a bit lower. Some other physiological parameters are more indicative of a more stressed state.
00:55:13
Speaker
And again, maybe we don't know what that means in terms of assimilating the training, right? As we discussed at the beginning. So it could be there are other implications, but in the studies looking at performance, then at the moment, that there are no strong changes that would, I think, make a coach decide that things should be modulated that way.
00:55:36
Speaker
think it's better at that point really to work with the individual and their feedback and how they feel they can execute the training and things like that and go really at an individual basis more than, yeah, with what we expect from what we see at the group level.
00:55:51
Speaker
Yeah. And it's one of the points that was made in one of our coaching discussions was that, one of the coaches mentioned that it brought up that the HRVs flagging a negative when neither he nor the athlete expected was brought up him asking the question to his female athlete, like, where are you in your menstrual cycle? And they just, and then found out like, and, and sort of solve the problem and then brought that to the but the surface of their conversation more. And, and he was able to do a better job of his coaching just because he was more aware of where she was.
00:56:26
Speaker
And like you said, I think that the, the problem has been what I want to say, like, false negatives or, you know, where we have training plan, but the, but it's signaling, no, you shouldn't train today because your HRB says so.
00:56:40
Speaker
And so I think it's, if nothing else, it's like elevating this more into, um into the consciousness of, of our decision-making and making us more aware of it. So, so I think that that's, that's great. And I think it's really interesting and I'm really grateful that there's new more research.
00:56:58
Speaker
coming out because this is something up until like honestly like just a few years ago I wasn't really tuned into or thinking about so it's it's new for me as a coach too. Yeah, yeah I think in any case it's key context ah so for some people and then it's important to use it as you just mentioned it could explain change in the data that you otherwise might think is due to something else so if anything it's context that is important that is there and then it can help um yeah the day to day.
00:57:28
Speaker
Absolutely. So shifting to it another ah variable that a lot of our athletes manage, and we touched on it briefly, is altitude. Our group goes, our athlete group goes sometimes to ah you know, almost 9,000 meters in altitude without supplemental oxygen. Most of the time they're using supplemental oxygen, but very, very high climbing, very, very high. And a lot of trail races these days, it's very common to see courses go 3000 meters now. Um,
00:58:02
Speaker
The climatization for these races and for these mountaineering objectives is is very important. what does he expect What is the expected HRV response to short term, like acute, I think would be the clinical term, but meaning ah in a short timeframe.
HRV and Altitude Acclimatization
00:58:23
Speaker
exposure to a new altitude. If someone is trying to climatize and they go from the valley and they go up and they so try to sleep at 3000 meters, for example, what would be the expected HRV response to that?
00:58:36
Speaker
Yeah, so typically i think studies looking at this have shown that we have a suppression, like we have an increased heart rate or probably people feel like the increased breathing rate, right? So there's some things maybe they notice, others like HIV is not something we can really notice, but then you can measure that there is a change and that the change seems also quite aligned with how high you go, right? So the higher, the stronger the suppression.
00:59:05
Speaker
I think what can be interesting there is that if you stay quite long, say in the order of some weeks, then you might see changes in the data that reflect that you are getting used to the environment.
00:59:21
Speaker
um I did a study during the my master's in which... We had a few athletes that went at altitude, and then we looked at how their HRV changed and their racing heart rate and also this coefficient of variation we discussed so much.
00:59:37
Speaker
It would jump around one day to the other. And then we put this in relation to But we could consider a marker of their adaptation, which was, for example, what's your heart rate at a given pace, right? So at sea level, you have a certain heart rate at a given pace. You go at altitude, heart rate at the same pace is much higher.
00:59:58
Speaker
But then, you know, after a couple of weeks, it sort of renormalizes. Well, maybe never like sea level, depending how high you are, but, you know, it gets better. So we could see that the people that had a greater disruption in the first week in terms of their resting physiology, so the RAV would jump around more, the resting heart rate was higher, then were the people that struggled more to adapt or respond according to this criteria of their heart rate renormalizing at altitude. So it remained basically elevated in a way that they never really adjusted to the altitude.
01:00:34
Speaker
So this to say that maybe also what happens in the first week could be telling something about how you will respond in the longer term. So if you have a great disruption, it's going to take you longer or maybe it's just too high for you.
01:00:47
Speaker
While if you have a smaller disruption, maybe you're just handling it better. And then also your exercise data will renormalize a bit quicker. Yeah, that's interesting. And, you know, when a few observations from having spent a lot of time at high altitudes, one is that there are people who respond to acclimatization well and acclimatize quickly and others that just take longer. um And even knowing myself and some of my climbing partners that came to know very well,
01:01:18
Speaker
I would know that some of them acclimated much faster, but I would catch up and we'd be equal after say four weeks or something. Um, and also that the body kind of learns generally to get better people who frequently go to altitude. Yeah.
01:01:34
Speaker
especially one or two or three times a year, their body learns how to do that. If you're ah um a mountain guide and living and when born and raised in the Chamonix Valley and you've been kinding climbing Mont Blanc every summer all your life, like your body learns how to acclimatize to 4,000, almost 800 meters. And it's and it's,
01:01:54
Speaker
And that becomes very normal and very easy for it. But if you take that same person and take them to 8,000 meters, that, that they may have a different response. Like that's, ah that's another, like it's the altitude, our conversation in the individuality of it is very interesting.
01:02:11
Speaker
Um, but I think that this is also what you're saying like this as a, as a signal is very interesting and I can see how that could be, really useful to track that for people. Did your studies or did your research or other research on HRV dial in? Like, uh, was there, was there predictability in terms of the the time to adaptation, ah with HRV and correlated to how subjective act acclimatization was or but was it just too individualized to, to come up with an average?
01:02:44
Speaker
Yeah, so the study I did was us very small samples, so we could only see a difference between two groups of people, the ones that we called that could respond well and the others that couldn't.
01:02:55
Speaker
I'm not aware of studies using a similar approach in which you look at the data in the first days to try to come up with what will will happen in the future. um Also because typically studies are a bit short also on this, um maybe evidence from the field would be able be more useful, know.
01:03:13
Speaker
How do you manage or ah accommodate the fact that sleep can be very fragmented at altitude? That's one of the things that moving to high altitude does. Is that, are you just focusing more on that waking, um, sit upright and do the measurement then and not, and relying less on the, uh, during sleep measurement?
01:03:37
Speaker
Yeah, yeah, I would think that's another reason to measure in the morning because then sleep is just another stressor, you know, positive or not, it will impact your state. Well, if you measure during then and maybe you are also awake a lot, then first of all, the movement.
01:03:54
Speaker
for wearables would create artifacts, but then also the data would be somewhat less representative of what we are trying to capture. So in your you know recovery state in a known situation context, because then it's quite different from the typical sleep.
01:04:12
Speaker
So in those cases, again, I think it's just a bit better to measure after there sleep or you're even if disrupted or anything like that. Yeah. shift of of topic, I want to think about the future of
Integrating HRV with Other Data
01:04:26
Speaker
coaching.
01:04:26
Speaker
And internally, we're developing our own intelligence engine for athletes and coaches. We call it we call her Maria. And her purpose is to help organize and analyze and prioritize the training data because they're we're just getting buried by training data these days, as you know.
01:04:46
Speaker
It's not meant to make decisions on its own. It's meant to surface patterns and help us know when to ask questions and or what how to ask better questions. If you're shaping the logic behind something like this, like how would you want HRV as a data point to be weighted relative to other data that we can collect with wearables and also relative to like the subjective feedback? Like you said at one point, you just ask your coach, your athlete, how, how do you feel? you know, that's one of the most important questions in coaching, right?
01:05:18
Speaker
How would you weight these different things? Um, and where would it, which, where would HRV be in a sort of priority list? Would it be, Number one, number three, number 10, top third. I don't know how to exactly quantify this, but how would that be for you?
01:05:33
Speaker
Yeah, so I think that in terms of the signals that we have to capture our stress response, stress being training or anything else, we have HIV resting heart rate. And then in the context of training, we can also look at heart rate during training. So that's what we have more than what would be best, right? is As we were saying earlier, like...
01:05:59
Speaker
At a hormonal level, so much happens and we have no clue. but So we just cannot look at it. So in the context of objective data points, we can look at, I think it's a useful one. So it's one I would look at. It's one I look at with the other psychos.
01:06:16
Speaker
um But again, always to me, I mean, the subjective feel is always the first, right? So the reason also to use the data typically is also to aid that self-awareness process of getting a bit more in tune with ourselves, also with heart rate during training, right? So it's not that we need to follow this blindly. It's more about...
01:06:43
Speaker
if we set a cap for what's an easy round for you, the idea is that we also start thinking about that. Like, how does your breathing feel? How everything feels subjectively as we set certain limits maybe because we want to learn those things so that you know at a certain point, any good athlete can train all the time without any heart rate. But maybe to get there, looking at the signal sometimes was helpful because you know you develop that self-awareness through the data.
01:07:13
Speaker
And I think also resting heart rate and resting HIV can serve that purpose at times. So I think it's very important to have it always in the context of let's get better at using feel and subjectively understand how we feel and all of that and making these decisions.
01:07:31
Speaker
Because eventually I think that should drive the vast, and very vast majority of the decisions. And then HRV is something we look at just to have that extra objective data point that still can pinpoint certain situations, but also sometimes can just give us confidence both as an athlete and as a coach. I think we are feeling good, the training is going good, but then, you know, also the data that reflects that everything is, you know, again, within your normal range.
01:08:02
Speaker
So it's still good signal to have. It's not there only to flag negatives. It's also there to show that the process is going, you know, well, according to plans and there's a suppression here and there because life happens, but overall, you know, we are not doing anything that is causing, you know, again, a negative physiological response or anything like that. So,
01:08:24
Speaker
Yeah. Those points of view. So if I have a tool, you know, that would integrate data from the athlete and the coach and so on for me, it would be one of the data points to look at together with the subjective of the athlete, because then that is always key for the decision making.
01:08:41
Speaker
One of the things that I think people have focused on it, I have inadvertently focused on it in our conversation. It was like the, the signal about today's workout or should I train today?
01:08:52
Speaker
The should I turn train today question or should I modify my workout? But when I have that discussion with an athlete, of course, I'm thinking about that day, but I'm also really thinking about it in the context of just sort of the training density of that week or even the the three weeks of the build cycle we're in or is next week the recovery week and we just have like...
01:09:15
Speaker
You know, two more hard workouts and I was going to do the hard workout today. Maybe I'm going to shift it tomorrow because I want him or her to feel like those kinds of things. This kind of idea of chronic load accumulation, hu is that something that we can utilize HRV in, in understanding?
01:09:35
Speaker
where people are at, like, especially like a, you know, the classic is a three week build one week recovery, right? Like as you build the volume and in a training block for sort of three weeks and you're accumulating fatigue, ah you know, and that's what you're trying to get the body to adapt to.
01:09:52
Speaker
Is there something that's connected to that concept that it shows up or is measurable through HRV or any of these? I think not necessarily. So I think through my experience over many years, I think often is a bit more of a lagging indicator.
01:10:10
Speaker
So that would mean that see that things suppressed in HRV and, you know, we are going down and so on. Typically, we already messed up when that happens.
01:10:22
Speaker
It's not that we sit a bit before and we manipulate training. So that's why I think HRV can only be used as a support system to a well-thought-out training plan.
01:10:36
Speaker
And it can never be training based on HRV, meaning without a plan. Because people also think that's the case. Like, especially if they get a wearable something like that, they would go hard basically every day or any time that the wearable says so. And then when things are not going well anymore, then it's time to rest. But that, of course, is not how you train. But, you know, it it needs to be said because that's how some people approach the tool.
01:11:06
Speaker
So the tool can only be used to make adjustments to a good training plan, I think. And in that context, useful. So sometimes, you know, just to manipulate what is your capacity to assimilate stress on that given day. Maybe it's not great. And then we push something another day, but it's more about small adjustments, more than the overall structure or long-term changes. So even if training goes very well, in certain situations, we might see that you're always within your normal range and maybe there's a trend in the data that goes higher, but then
01:11:40
Speaker
It's difficult to... Like, you still need to deload at a certain point. are you I think the data will not tell you that. So you need to do it before you see it in the data. So from that point view, I think as a coach, still you need to start from your tools and your thinking of the athlete and their planning and so on. And then use HRV as a feedback, day-to-day feedback or short-term feedback.
01:12:05
Speaker
But it's not always... um yeah so tightly coupled to what is happening at the higher level or it just lags a bit in terms of um showing certain types of changes.
01:12:18
Speaker
Yeah, that's that's and that aligns with my experience precisely. So it's really good. And I was, I mean, because I'm not an expert in this, I was wondering if I was missing something, to be honest. So it's good to get that confirmation from from you.
01:12:32
Speaker
So one final question, if you could design one physiological metric to measure that doesn't currently exist or maybe is in its infancy somewhere, a true, true sensor for human performance, what would it measure? What would it be? What what would you, what is your dream measurement that you would like to create, to have as a coach? Great question. um I don't know, maybe I never even thought of something that we cannot measure, but I would like to see more of the things that happen in the body that we know that are happening. Like we were discussing earlier at a hormonal level, like I'd be so curious to see what is happening, you know, even events just outside of stress hormones and cortisol and so on, but even related to training and how those things...
01:13:27
Speaker
change in relation, i would say, because a lot is done acutely. Like, okay, you do a work for this type of workout, this type of intensity, this is what happens. This has been done in the lab.
01:13:38
Speaker
But again, what happens long term? What happens over a training cycle where we stress this specific capacity? Or what is our capacity to assimilate stress at a given point?
01:13:52
Speaker
And is there anything in the body actually that can reflect that? Because maybe we have the same, let's say, physiological makeup in different situations. And once we respond very well and improve, and the other time we don't.
01:14:05
Speaker
And why is that? it's a bit the art of coaching. But at the same time, makes me curious. like Is there anything there we can look at that could predict how we respond? Because even with HRV, there is some research, very little, that shows that, for example, when our HRV is...
01:14:25
Speaker
chronically a bit higher, we might actually be able to assimilate more training. So even though HRV guided training is always about holding back when the HRV is suppressed.
01:14:37
Speaker
So it's more about, you know, not doing something, reducing intensity and so on. There is also some research that that shows that when it's higher, actually you might be able to assimilate more.
01:14:49
Speaker
And of course it's difficult, especially we talk about running is a high-impact sport, so you cannot just add a workout. You risk to break the person. It's not just about the nervous system. Like, there's so much more that you need to be careful with.
01:15:03
Speaker
But maybe in a spot where there's less impact or maybe in certain situations, you could do something with that information. and I think we know too little about that. So something I'd be intrigued um to know more. as we Yeah, I think the hormonal aspect would be... My answer would... I was thinking about what my answer would be. And not not that you'd be interested, but it was I came up with the genetic like response. Like what... Yeah. At the genome level, what is, what is triggered? What is, what signal, what, um, yeah, what, what are the, what is the genomic response of prolonged training and how does that change? Because for sure, all of us that have done this for a whole lives or for a long period feel our bodies physically change, right? Like something is happening at a very, very, very basic level of the cause.
01:15:55
Speaker
but it's changes at the, even at the, um, at the, what did the morphology level? Like, don't know, when I was climbing full time, I was so lean.
01:16:07
Speaker
mean, I'm not, now I'm 55 and I don't climb full time, but I'm not, you know, my body still sort of holds onto that, even though it doesn't have this demand on it placed on it anymore. And I think, you know, that's, that's, I think that's entirely part of the process of having been climbing and training for seriously for 25 years. And I, I don't know that. I mean, I'm an N of one, right? But I think that it would be super interesting to to know. yeah Yeah. Well, develop the app to measure hormones with the phone and the genome. Yeah. Yeah. I don't know some things. Maybe it's better not to know if you know too much about genetics before working with a person, you might lose hope too soon sometimes. it is Yeah.
01:16:53
Speaker
hu Well, on that note, thank you so much for all your advice and expertise on this interesting topic. It's kind of a ah special place where it's this intersection of human physiology and science that you know and technology. And I think that as technology has just feels like it's just going faster and faster and faster every day, it's a fascinating space to spend some time and think about and learn from an expert like yourself. Thank you so much.
01:17:25
Speaker
Thank you for having me.
01:17:40
Speaker
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Speaker
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