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Lindsey Hunt on Sweat & Racing in Hot Conditions
865 Plays1 month ago
Lindsey Hunt of Precision Fuel & Hydration joins Michael to talk about his research into sweat, his novel sweat rate calculator, and his recommendations for maximizing performance in hot conditions. Lindsey covers:
-sweat rate and replenishment strategies
-why dehydration is a more serious performance limiter in hot conditions
-passive and active heat training for acclimatization and performance
-in-race strategies for controlling core temperature
Listen also to our Episode 116 interview with PF&H founder Andy Blow to get a deeper understanding of the role of electrolytes and carbs in hydration.
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Transcript
Introduction and Guest Error Clarification
00:00:00
Speaker
Hey folks, this is Michael and I am thrilled to be talking to you again on behalf of the Endurance Innovation Podcast. ah The interview you're about to hear with Lindsay Hunt from Precision Fuel and Hydration is the first one that we've recorded in just about two years, actually, and there's a little bit of rust in the, let's say, the interviewing style. and I've got one correction already to make. um During the interview, I refer to Lindsay's company not as Precision Fuel ah and Hydration, which is, of course, there their name. um And so I do apologize. Keep that in mind as you listen.
Lindsay Hunt's Academic Background and Research
00:00:50
Speaker
Hi everyone, I'm Andrew. And I'm Michael. And you're listening to the Endurance Innovation Podcast.
00:01:09
Speaker
Listeners, welcome back to Endurance Innovation. Joining me today is Lindsay Hunt, who is a sports scientist with precision hydration and nutrition, specializing in all things that get us sweaty. ah Lindsay, ah if you if you don't mind, please introduce yourself, give us a little bit of ah your interests, your academic background, and how you got to be where you are today.
00:01:34
Speaker
For sure. Thanks for having me, Michael. um My name's recently actually Dr. Lindsay Hunt that's been fully approved for the PhD. So there we go. It's a nice little update for us. That's a that's a good fact track right there. So we' ah moving forward, I'll be calling you Dr. Hunt. Appreciate that.
00:01:50
Speaker
um My background, I've recently just completed my PhD at the University of Sydney in environmental physiology, where for one of the studies in particular, we looked at um whole body sweat rates during outdoor physical activity, mostly in cycling, but also in running. And so we developed a few biophysical equations or used a few biophysical equations that could help us predict from environmental conditions and what people um ah pat People's power outputs and metabolic rate, we can predict their sweat losses to a high degree of accuracy. um And the other side of my research is looking at heat acclimation indoors and using that to improve performance. Cool. And so those are sort of main areas of my interest.
00:02:38
Speaker
Awesome. um Well, very relevant to what we're talking about today, of course. That's perhaps why you're a guest on the show. um But why why the interest in in heat acclimation and sweat rate? what's ah What drove you in that direction?
Hydration and Motivation in Endurance Sports
00:02:51
Speaker
For sure. I mean, during my research, my original sort of research piece was in caffeine and how caffeine affects thermoregulation. So I've sort of always been, I did that in my master's by research at the University of Sydney.
00:03:05
Speaker
And I've kind of always been interested in this sort of area since doing my undergrad in sports science. There was always this I guess interest in how the human interacts with the environment and how we can sort of best shape that performance in extreme environments, for example. Cool. So if someone is going to Kona, what what are the best things they can do? If they get dehydrated, they're not going to be in a great shape. If they aren't heat acclimated or if they're not prepared in the best way, they're not going to be in a great way to race very well. um And I think
00:03:38
Speaker
definitely in the last 10 years, things have gotten a lot stronger there in terms of the research, the science and what people are doing. But certainly, you know, 20 years ago, 30 years ago, not many people were focusing on hydration or um heat acclimation or heat preparation as much as they as they should have been. And so it's just an area that's quite exciting for me.
00:03:58
Speaker
Cool. I think that's an awesome answer, but what really I was fishing for there with my question was ah some kind of anecdote of you passing out in a hot race or something, and then you realize that this is some this is an area of study where you you wanted to learn more. But your answer is much better than that, I think. Not quite. Unfortunately, I've never had a case like that. I'm just trying to think now.
00:04:22
Speaker
i've had I've had instances where I've been racing in the heat and realized I should pace things better, but I've never gotten to that point. Yeah. i was ah where i was I think i it was Instagram or YouTube or something. so it It showed me like a blast from the past. I think I may have commented on this video. It was when it was an ITU race where the Brownlee brothers, when ah when ah Johnny carried Alistair across the finish line because he he couldn't you know he couldn't even keep a straight line anymore. and it was ah
00:04:53
Speaker
It was almost like sad, funny watching this video. And I know that i i I definitely have never pushed myself to that extent either. But I could totally sympathize with the guy. like he was He was right there. The finish line was so close. I mean, he was going for gold. I've never been in that place, but he just really wanted
Joining Precision Hydration and Company Culture
00:05:10
Speaker
it so bad. But the body was was saying no more. The body gives up at a certain point, doesn't it? You see, it it's it's so common in um Olympic distance triathlon.
00:05:22
Speaker
Yeah, it's mental because they they do a lot of events in sort of warmish conditions, but not that warm. and then And then it's just the high metabolic rate and and the motivation that leads to events usually right at the end. Yeah. And it's interesting because you're talking about motivation and that's something I want to touch on a little bit later because I have a question for you from that sweat study that you mentioned in your intro. um But it's interesting that the motivation is such a key component and I would probably argue that the folks who are at the top of the their game are the ones who are obviously the most motivated and the ones who probably run into this more than like Joe's like me. Definitely, definitely. um Motivation comes down to pushing yourself and going past those physiological signals that we get to tell us to stop. And so when you are incredibly motivated, you can push yourself through that. Cool.
00:06:13
Speaker
Okay, so ah just one last final touch on your on your bio. um ah You are now with ah precision hydration and nutrition. And we've had Andy on the show a couple of times in the in the before times when the podcast was a regular feature.
00:06:29
Speaker
And he was he was gracious enough to come on for a second time. And and he talked a lot about you know he talked a little bit about sweat rate, which we're going to talk about today. He talked about you know sodium loss. ah So he was a great guest. He, you know listeners, if you want a bit of a primer for today's conversation, definitely check out those episodes with Andy. And I'll put them put links to them in the show notes, of course. But how did you find your way to precision, hydration, and nutrition?
00:06:54
Speaker
Well, they put out an advertisement for a job that they were looking for for a senior or a head of sports science. um And I originally applied for that. And they realized that they needed two people to do that sort of job. They had enough work to go go for that. So they ended up hiring Dr. Sam Shepard as well as as myself at the same time.
00:07:16
Speaker
Um, and yeah, that's sort of how that happened. Cool. Yeah. Straightforward. I, uh, but yeah, like I, like I, like I maybe, uh, suggested I have a lot of respect for them because of the kind of work that they do and the kind of like, you know, how upfront they are with, um,
00:07:33
Speaker
with their research and and sharing their information and their knowledge. and that's that That really always speaks to me as kind of ah you know an armchair athlete and also a a coach and just a curious person. It's always it's always fun to work with folks who are we're not hoarding that information that they've acquired. so that's ah I'm sure that's a cool place to be.
Precision Performance Lab and Future Plans
00:07:54
Speaker
That's one of the key aspects of the new precision performance lab that we're building and that's built and we're developing further. So one of them is one of the whole points of that lab is to be able to have a place where we can stress test different devices, test different bits of kit and then put out our opinion on these um these devices, say, yes, this is great. Yes, this is bad. Or no, this is bad. And so that people like you that or the general consumer can go and say, hey, should I buy this? Is it going to be worthwhile for me? um from and And we can give them that opinion. That's that's sort of one of the the whole aspects of the new lab. So it's very exciting. Yeah, that's awesome. That's something that I, uh, I missed in the intro, but, uh, yes, as you, as you said, PA, precision, hydration, nutrition, have a new, have a new lab. Tell it, can you, you want to tell us a little bit about it? Cause that's something that, that we probably, it's not maybe directly related to the conversation, but it's an interesting piece of, uh, of tech news that we should cover.
00:08:48
Speaker
Yeah, for sure. So, I mean, it was sort of built over the last so two months. um It's essentially an environmental chamber or two sort of rooms with an environmental chamber where we can control the environmental conditions. um And we're using that lab firstly to heat acclimate athletes. Cool. Excuse me. Heat acclimatise athletes, or heat acclimate athletes rather.
00:09:11
Speaker
um preparing for hot events. So if people are going for Kona, we can get them in for a couple of days to 10 days do like a specific heat event preparation block. And then for other athletes, maybe they want to do more long term heat acclimation, they can come in for a few weeks and develop some more robust hematological adaptations for performance in the cool, they can come along and do that. And so those are the two big services that we offer, um as well as lactate profiling and sweat sweat testing as well.
00:09:40
Speaker
Very cool. OK, well, um maybe we'll put a pin in that one. and we might ah kind of my My dream is maybe you come back, and then we can talk specifically about that lab and and some of the work that you're
Predicting Sweat Rates and Hydration Strategies
00:09:52
Speaker
doing. Because sure what i what I asked you to come on today was a little bit different, but I'm very interested, especially as you folks get rolling and getting and starting getting some of the data um on ah on both athletes and devices, it'd be really interesting to hear what you're finding.
00:10:09
Speaker
But um yeah, that's so as I said, let's put a pin in that one. So ah today, we're we're primarily looking at at the piece that you contributed to um called the Old Body Sweat Rate Prediction, Outdoor Running and Cycling Exercise. And folks, I'll put a link in the show notes as I usually do. And this was, I believe, the piece that you mentioned earlier in where you what you were talking about creating a calculator.
00:10:33
Speaker
or a means of estimating a sweat rate. So tell us a little bit high level of ah why this was an important piece of research for you, why this ah being able to estimate um this parameter of athletic performance was an important one.
00:10:51
Speaker
I mean, when it comes to thirst and hydration or hydration and thirst, a lot of people are able to drink too thirst and be comfortable with that, but not everyone is. um People learn how much they need to drink in certain environments, certain um exercise intensities, and and they'll sort of be fine. But for a lot of people,
00:11:11
Speaker
It helps to have an idea of how much fluid you're going to need to bring. So for an Ironman tricelete, for example, planning and forecasting is something that's hugely important. So if that you're going to go out and do a race um and you're not sure if you need to drink half a liter or an liter per hour.
00:11:29
Speaker
you're going to be in a vastly different different situation if you're under drinking by 500 mils an hour over the course of a nine, 10 hour triathlon. So on top of your hydration status in that respect is from a planning point of view of saying, okay, I know I need to bring roughly this amount of water per hour on the bike and the run.
00:11:47
Speaker
will help people perform better in the heat for a lot longer. And so coming back to that, when you're exercising in the heat, the impact of dehydration is much worse the hotter it gets. So in 10 degrees, the impact of dehydration isn't actually that dramatic. But if you're 2%, 3%, 4% dehydrated in 30 degrees, the impact on your performance is is amplified. And so if we can interestingly maintain hydration status across all conditions that will help essentially. Awesome. Okay. So there's, you said so many things that I want to follow up on that I'm just, uh, try not to forget all of them. First of all, uh, you're speaking my language when you're talking about, you know, planning for a race. And it's, it's really interesting. And I think it's something that you mentioned earlier, how we're only fairly recently started starting to really pay attention to this because people have had power plants for as long as there've been power meters. And now we have,
00:12:42
Speaker
power plants that are really detailed, that that will take into account elevation and even you know aerodynamic information like wind speed and and ah you know certain positional changes. So we've had power plants, and I've created power plants as a coach before, but and hydration and nutrition plants, we've had those too, but they we haven't we've more recently become to come to understand how important they are and really how to make them um, more individual to the athletes. So you're totally speaking my language there. The first thing I want to ask you about is, um, a bit of a digression, but you talked about the thirst, um, the thirst response. And then you mentioned people can learn, can learn if I'm, and I'm paraphrasing you, they learn how much they need to drink. So is it.
00:13:26
Speaker
Is it just trusting the thirst response or is it learning how much you need through trial and error? And then maybe coupled with this tool that you folks have developed, like where do you land? Because I know that that at least for, for some time that was a contentious topic of, you know, do you drink the thirst or do you create some kind of strategy? Where do you fall on that?
00:13:44
Speaker
Yeah, so I think a lot of the evidence points towards the 2% as sort of a 2% of body mass loss as a significant threshold for the first response to improve or increase. Okay. um And so when you get to 2% or less or lower, you're already at this point where you're reasonably tight dehydrated and 2% probably isn't going to affect your performance in shorter events or cooler events too much. But as soon as you start to get to hotter events, your performance already at 2% is going to start to get impacted, especially in sort of high intensity.
00:14:21
Speaker
Um, races. And so if you're getting to that point, that's generally where the thirst response becomes quite strong for a lot of people. And so at that point, as people have said in the past, it's almost too late. Um, and so you kind of need to have this blended approach where you, you are planning, you are drinking proactively, but of course you're not drinking just water and you're not drinking to try and maintain your body temperature for, I mean, you're,
00:14:50
Speaker
your body mass exactly at 100% for that the course of the race. You need to allow for some deepup level of dehydration, otherwise you'll um run the risk of hyponatremia or or other other issues for sure, especially if you're not drinking anything with um sodium in it.
00:15:07
Speaker
Yeah, that makes a lot of sense. And well, I do want to come back to to sodium in a little bit. um one thing that One thing I do want to touch on is, so you've you've built this calculator, which somebody who is maybe who hasn't gone through this process before can, I imagine, access and and create a little get an understanding of of a ballpark of where they need to be with their hydration. um Can we talk about some of the limitations of the of the calculator? Because whenever, that's always my first question, is whenever somebody gives me a tool, I'm like, OK, well, how do I break it? Or where does it not work? or how How much how well can i trust it almost um so one thing that i noticed was ah there is a fairly broad range for the ninety five percent confidence interval um especially in in runners um um actually no it looks like it's about the same running and cycling yeah ballpark the same.
00:15:56
Speaker
So how do you approach the the fact that the error bars are are quite large? And on the order of just looking at your study for runners, it was, um again, this is 95% confidence interval. So this is obviously almost everybody. Plus 44 and minus 0.44 and minus 0.38 liters per hour. So that's not insignificant breadth of a range.
00:16:19
Speaker
No, not at all. And I mean, this was the the first study employing this sort of approach outdoors. And so there were so this approach has been done indoors and it's seen indoors, we've seen up to 90, I think 95% of the variance explained by this type of model. um okay And that's that's an indoor environment where we can control everything a little bit more, we can measure people's metabolic rate, we can measure the environmental conditions much more closely and they're much more, let's say, consistent across the trial. um And controlled, yeah. Controlled. So there's a few there's a few different sort of things going on there. like one of the The big thing here that's increasing the variability is people's metabolic rate. So we used we're estimating metabolic rate from people's running speed without any indication of their running economy or cycling economy sure as well.
00:17:17
Speaker
And so some of those, I guess the larger errors are ah probably due to people with higher or lower running economies than the average, leading to over underestimations. That's probably the biggest cause of any big differences we have there, to be honest. Yeah. That makes sense. That makes a lot of sense. I think on cycling, I'm with you on running. On cycling, I think like The economy in cycling, at least, and correct me if I'm wrong, because I'm sure you've seen more research than I have, but and I think in cycling it's a little bit tighter. like If you've got a good power meter, you're you're probably close to 25% of mechanical energy. you know Mechanical energy is 25% of metabolic energy, plus or minus. There's definitely a little bit, but it's not it's not from why the when I was reading the research, this was some time ago, not nearly as much um
00:18:08
Speaker
variability in economy in cycling versus running that is. Yeah, definitely. I mean, pretty much everyone is somewhere between 23 and 25%. I think pro cyclists do get up there. um on On average, they're they're a little bit higher than the rest of the bunch, but it's it's it's a hand so ah handful.
00:18:26
Speaker
they they They have peddled a lot of circles in their lives. Exactly. um And my other question is, ah why not just ah go to the the tried and true, you know weigh yourself in the nude.
00:18:39
Speaker
go exercise, weigh all the the fluids you took in, try not to pee, and then weigh yourself in the nude again versus using the calculator. For sure. I think, I mean, I think that's a great idea for people to do to sort of help themselves validate this sort of modeling. um For a lot of people, they'll see this and they they might not trust it.
Sweat Rate Models and Real-World Applications
00:19:01
Speaker
They might not want to use it um for whatever reason. um And one way to sort of build confidence in something like this is to go and collect your your own data um using that you know like gold standard method and compare the data that you have from that to this. And if things vary quite well, then of course that builds confidence in it.
00:19:23
Speaker
And that means that then you don't need to go through that extra faff of weighing yourself before and after exercise, making sure you're doing it nude, making sure you're weighing the bottles correctly, making sure you're going for 60 minutes, but not over 90 minutes, making sure you're doing all the right things to measure that body mass properly.
00:19:42
Speaker
um without introducing your own errors just from that. And a lot of the lot of the time, people's um scales at home aren't necessarily so accurate. A lot of them go to 100 grams, for example. So 0.1 grams. But if it's if it's repeatable, then you're probably OK, right? It's repeatability versus accuracy here, maybe? Potentially, potentially. But I mean, those scales, we don't know. That's just 50 bucks that off they've they've bought off Amazon a lot of the time.
00:20:09
Speaker
I mean, the scales we used in this study were a few thousand dollars. So ah yeah, there's a different property accuracy there as well. So like, yeah, you could be, you could be 200 milliliters off just from your own scales, not reading properly each time.
00:20:25
Speaker
What you're saying right now totally resonates. I wonder if you could use both and then calibrate the calculator to your own, you know, so you can see where you fall in the range of the calculator. If you're under over right in the middle and then moving forward, use the calculator, you know, do a few a few of the the gold standard.
00:20:42
Speaker
you know, nude wins and then and then ah moving forward, use the calculator. Because one one thing that I could see as ah as a use case is I live in Toronto, Canada, right? it's It gets hot, but it's, you know, it's it's hard to simulate some of those like Kona conditions, especially if I'm, you know, if I'm ever fit enough to go to Kona. I don't know that that'll ever happen. But you know, that's late October for us. Yeah, it's true. Right now, it's we've had a really warm spring, but it's still maybe 14 degrees outside and really nice and sunny and beautiful. But it's not, you know, in Kona, it's 30 degrees and 70 percent humidity or something like that. um And ah for me, if I want to know where am I at?
00:21:24
Speaker
a week out of Kona, two weeks out of Kona, maybe I do this, you know, maybe I i do the the the calculator using conditions that I do not have available to me at the time because it's much cooler where I'm training. So that might be ah an interesting use case, too. Definitely. I mean, that's one of the biggest applications I see for this type of stuff where you can you can be from a cold environment and you're going somewhere else to race and you say, OK, what am I going to need to do? Because obviously you can't you can't can't test that out at home in 10 degrees when you're going to go race in 30. That's just not feasible. um So yeah, that's one of the biggest applications for this. So forecasting is is fantastic. Okay, very cool. Okay, I want to switch gears just a little bit. I'm still staying with the study though. There was one finding that I found that was super interesting to me. And this is something that I
00:22:15
Speaker
as one of my pet interests, for sure. And that's like the ah the the perception of effort, or in this case, the perception of thermal comfort. um One interesting ah finding of yours was that, um and i'm just goingnna I'm just going to read it from your abstract, that ah substituting measured environmental variables with subjective assessment of climatic characteristics reduced the variation in observed sweating described uh, by the running model by up to 25%, but only by 2% for the cycling model. So if I understand correctly, um, the way that folks felt when they were running influence sweat rate considerably more than it influenced while they were cycling. Did I get that right? Or did I misunderstand kind of, I think that comment is more reflective of.
00:23:04
Speaker
the error that peoples that we saw in the we when we used the subjective measures of environmental conditions versus actual environmental conditions. So we took and i we we we collected data from people and asked them what how hot they thought air temperature was, how hot they thought the sun was, how hot windy they thought it was, and how humid they thought it was. okay Across a ah sliding scale, I think it was from zero to three We need to double-check that um from 0 to 3. And they would just rate how how hot or how humid it felt. And so what we did was we substituted those for the environmental conditions. So if you didn't have environmental condition data, could you just plug in a 0, 1, 2, 3 into the model? um And the error okay that we received from using that was higher when it was running and lower when it was cycling.
00:24:01
Speaker
my theory would be that when it's for people that were running you kind of have this larger impact of the environmental conditions on you depending on how you're feeling because you're not getting as much air flow. And so if someone's going easier, um, they'll say it's cooler when it's compared to if someone or that same person was running faster in the same conditions. Cause it feels hotter. It feels sweatier, but it's not necessarily actually hotter interestingly be leading to some of the variability there, but less so when you cycling, cause you're just kind of always, most people always going between 28 and 35 Ks an hour.
00:24:45
Speaker
And so the impact of the environmental conditions, if it's 20 or 25, is less, let's say, on their subjective responses. Yep. Yeah. Cause you have more of that, uh, more of that, uh, cooling, like convective cooling, or even exactly the force of operative cooling that happens. Yeah. Okay.
00:25:03
Speaker
That makes a heap of sense. It's not how I understood it, but it's still a super interesting finding. Thank you. Yeah. I guess that, that, that sort of little, um, test was just to say, okay, if you don't have climactic conditions, what, what can we do? Can we use people's subject subjective responses? And I guess to that, if it's 25% running 2% cycling, you can when you're cycling, but not when you're running.
00:25:27
Speaker
yeah okay butlan Okay, so I want to move on to some of the kind of some of the the takeaways and maybe the practical applications of of a study like this. short of you know Now there's a tool, and I think it's it's free to the public. right there's ah There's a URL that folks can go to. and Yes, that's correct. So other than you know there's this there's this tool that has a pretty good repeatability, because he had a pretty big sample size, I remember. it was like hundreds of folks, 188, 182 runners, 158 cyclists, which is in sports studies. In my experience reading sports studies, it's not like 12 college age males, you know, it's a little bit more than that. That's quite a lot. OK, so then ah now, Lindsay, I got I got a couple of questions for you that to relate to, you know, sweat and hydration, but maybe not necessarily to the study. So this is just picking your brain and based on your experience, both in academia and then
00:26:18
Speaker
your tenure with precision, hydration, and nutrition. um Let's talk about ranges. So we we talked about error bars and on the on the calculator. um But what have you seen, again, either in your study or in in the field, in terms of how much do people actually sweat when they're engaged in this exercise? What's the what's kind of like the minimum and the maximum that you've observed?
00:26:40
Speaker
and the I mean, the minimum it it just entirely depends on all of all of people's sweat rates are individual, but it depends on people's metabolic rate and their body shape and size and the environmental conditions. So The minimum I mean, you see it could be as low as 100 mils an hour or nothing if someone's just walking in zero degrees, for example. Sure. Okay. But anyone doing sort of any sort of race activity in cool environments, it's usually around 400 to 500 mils an hour is sort of the lowest you'll you'll see. Okay. Maybe on the bike in ah in 15 degrees, for example, during a 70.3. And then
00:27:20
Speaker
in the lab at least let's say at 40 around 40 degrees 40 humidity we've seen someone lose around 3.3 liters an hour which holy smokes okay which is enormous um and obviously unsustainable yeah Yeah, I can, I can't imagine like that, how you would even, ah the follow up question I have for you is like mitigation strategies, but, or like replenishment strategies rather. But, um, I don't know that you could, you really have a good strategy if you're losing more than three liters an hour. Not quite. I mean, you you basically can't.
00:27:54
Speaker
I don't think anyone can replace that. Maybe maybe they can for an hour. This this individual individual drank, I think, one and a half, two liters during that start during that but that session. um So, I mean, he got kind of close in a way, but still quite far off, especially if you drag that out over hours and hours and hours.
00:28:12
Speaker
yeah Um, the big thing there is this individual at least is is incredibly fit and he's able to sustain that work rate throughout that session without getting too hot, which a lot of people would not be able to do.
Physiological Impacts of High Sweat Rates
00:28:27
Speaker
Um, and for him to be able to sustain that sweat rate for that amount of time is just incredible. Um, but he probably wouldn't end up racing at those sweat rates, for example.
00:28:41
Speaker
Yeah. Cause there's, there's some, there's some serious issues with, with losing that much fluid that fast, right? Like even just from your, on your VO two max, that there's a, that's a lot of plasma being diverted to not the working muscles, right? Like to the periphery. Oh yeah. Yeah. His beauty max would have been in the floor relatively for that, for that session for sure. Yeah. I mean, but 40, 40 Celsius is, uh, is pretty, is a pretty atypical racing, uh, racing condition, I guess.
00:29:05
Speaker
In a way, yeah. um But I think it's more the humidity in that in that particular environment. So this individual did race Western states. So it was certainly up to 38, 40 degrees, I think, at times, not throughout the whole race. But it was in California. So it was 30, 38, 40 degrees, and 20%, 25% humidity. So a pretty big difference in humidity, where it was much drier. And also,
00:29:32
Speaker
Let's say his exercise intensity would have been a little bit lower, but to be honest, not that much lower because he was racing. Okay. So in terms of replenishment strategies, you mentioned this, uh, this athlete was able to do one and a half plus, uh, liters per hour, at least for the, I guess it was the duration was here for, was just the 60 minutes, right? It was 60 minutes. Yes.
00:29:52
Speaker
Yeah, do you think that's so two questions here. So kind of um what should our targets be? Let's say we know what our sweat rate is, whether or not we use the calculator or we use the weigh in method. um How much should we be looking to replace? What are the factors that go into that decision? Is it race duration, I imagine, or is it you know, the, the absolute sweat rate number. Um, and then like, how high can we reasonably go? And let's say we're doing something that's long, like that is a half distance or a full distance iron, uh, our mentor. Yeah. I mean, the biggest factors, as you sort of touched on our, um, uh, race duration, so you can tolerate. Then the reason for that is because you can tolerate a higher level of dehydration for shorter durations. So if you're doing a 70.3,
00:30:41
Speaker
you can tolerate a little bit more dehydration for ah like for that shorter duration. But if you were to go on the limit of 2% or 3% for longer during a full Ironman, you'll probably see impacts to your performance um that will hurt you.
00:30:58
Speaker
more so than if you were more on topic of your hydration there. So essentially, the longer it is, you want to replace a higher percentage of your sweat losses. so Okay. The warmer it is, or the more humid it is, the more sunny it is, the more thermally stressful it is, let's say, you want to replace a higher percentage of your sweat losses. So again, if it was a cool 70.3, you could probably get away with not replacing as much.
00:31:22
Speaker
um But the impact of that dehydration would be greater if you're racing in a much warmer 70.3. And so that's where you want to replace a little bit more. I can't give you exact percentages. Essentially, most of my suggestions to athletes will be you want to end up at the end of your 70.3 or Ironman triathlon between two and 3% of body mass loss, but you only want to get there during the run.
00:31:52
Speaker
So you don't want to start the run already 2% dehydrated because a lot of, a lot of the time for the same relative effort, your sweat rate will be much higher on the run. So we're talking for an average athlete, maybe going from in average conditions, going from one liter per hour on the bike, your sweat rate, maybe that's a slightly above average athlete.
00:32:12
Speaker
one liter per hour on the bike to one and a half liters on the run for the same sort of relative effort, the same environmental conditions. Interesting. And that's because of the way these biophysical interactions work where your metabolic rate is a little bit higher when you're running, you're getting less convective cooling when you're running sure and your sweating efficiency comes down.
00:32:32
Speaker
Yeah. And if, you and being realistic, if you're doing a triathlon, when you're running, it's hotter and you're guaranteed, right? I mean, it's, it's later in the day, the sun is higher, the ambient is going to be higher. Yeah. So it's the, the, the environmental load is going to be higher. Um, almost always. Yeah, exactly. And so you don't even.
00:32:53
Speaker
Yeah, you don't want to end up starting a marathon or half marathon already quite dehydrated. That's part of the reason why you try and target at least matching or getting close to matching your sweat losses on on the bike and then starting to run in the best place you can. That's an awesome starting point. But um now, two or three times now you've mentioned, and I'm going to ask you a follow up,
00:33:13
Speaker
yeah that um dehydration is more detrimental in ah warmer conditions and cooler conditions. i' have this is the first I mean, intuitively it makes sense, but this is the first time I've actually heard it said that way. So now I want to know why. The biggest thing is is blood flow. So as it as it gets warmer, your skin demands more blood flow. And so if you're already at a reduced level of blood plasma volume from 2% or more dehydration,
00:33:42
Speaker
the impact your votmax is is just greater and so your relative intensity just increases dramatically. Understood. that makes that That makes a lot of sense. And then, of course, at the the earlier point you were making, if we're talking triathlon here, which most of our listeners probably are triathletes, as you're switching to that run, it's as I just said, it's hotter and the later in the day. Plus, because you are the there's the lower convective airflow that we talked about earlier, it's going to be it's going to compound that factor as well. You're getting less help from the environment.
00:34:16
Speaker
Yeah, definitely. And less help from yourself because you're not moving as fast through the
Sodium and Hydration Strategies
00:34:20
Speaker
air. Exactly. Right on. Let's touch on sodium and other electrolytes. so there's ah this is ah I think Andy and I covered this fairly well in one of those one of those two episodes that I'm goingnna i'm going to put show notes to or a link in the show notes to. But we should talk about it, at least touch on it here. um My first question is, Is sodium the only thing we need to worry about or are the other electrolytes in an acute sense of like, you know, a single event, single day event? Is that something that we should be thinking about replenishing as well?
00:34:52
Speaker
Most of the time you don't need to worry about it too much. I mean, they're the minor electrolytes that you do lose. And so for most people, most of the time, the general athlete, if you're taking on board, say some of our products or other products, you're generally getting enough of these minor electrolytes. And so most people don't tend to need to need them or need to worry about them. um There are circumstances where if someone does sweat,
00:35:20
Speaker
a large amount and a large amount of electrolytes that you you might need to consider your chloride losses. and okay We've seen this in a couple couple of athletes where they have quite substantial sodium losses. And along with that, you get a lot of chloride losses. And so a lot of products, including ours, mainly focus on sodium citrate, which is one type of sodium that doesn't include chloride. And the reason for that is generally we see that um gastric upset is much lower or basically non-existent with sodium citrate but if you start taking a lot of sodium chloride you'll often start which is just salt you'll often start GI discomfort and so that's the primary reason for that in my understanding.
00:36:03
Speaker
um these are These athletes are few and far between that need to worry about these things, but they do exist. You'll generally start to know ah ah to notice it yourself if if this is an issue like potentially an issue for you, where you' you you'll potentially end up in the medical tent with hyponatremia and certain other conditions. and That's due to chloride loss? Due to chloride loss. We're not hyponatremia, let's say, but So if you're if you are ending up in the medical tent, it may be worth putting a little bit of sodium chloride with your sodium citrate. I like sodium citrate, like I kind of make my own drink mix just because I'm cheap and I can get all the bits. But yeah, I prefer sodium citrate just because it doesn't taste as salty either. You know, the the flavor of it is more... is more mild. It's not at the concentrations that I want. And I have done one of one of your sodium tests. um It's yeahre getting all of that from sodium chloride, it would be difficult to difficult to stomach. I mean, I don't know what subject but the the taste is, it would be quite strong. Yeah, it's tough. I think and just to reiterate, those though athletes are very few and far between like 99.9% of people don't need to worry about this, but fair enough it it does exist out there.
00:37:17
Speaker
What, what out of interest is your sodium lost? So that's sodium concentration. Oh, it's just, I'm pretty average. So I'm just over a thousand milligrams per liter. Right. Okay. So I don't, I don't have to worry too, too much about it, but I know I've worked with folks who are north of 1500, 1500, 1700. And those guys are like, okay, you really, this is something we really have to pay attention to.
00:37:38
Speaker
Yeah, definitely. Especially if you're going over a 70.3 distance where you can just, issues start to get more and more and more with those athletes. Absolutely. So let's stick to sodium. If we're saying that the other minor electrolytes are ah less critical, is ah sodium concentration in the sweat correlated to the sweat volume or are they largely independent?
00:38:00
Speaker
and Yeah, they're definitely independent. okay So your net, your net losses will obviously net losses of sodium or will be higher if you have a higher sweat rate. And you generally have a higher sweat rate if you're fitter, because you can sustain higher sweat rates for longer, for example. So that as I was talking about 3.3 liters an hour, potentially some, some people could sweat that much over 15 minutes, 20 minutes, 30 minutes at race intensities at their maximal sort of efforts.
00:38:28
Speaker
but they certainly probably couldn't sustain that for and a whole hour let's say so it does depend on your fitness somewhat um and so yeah the sweat sodium concentration is is largely independent of your sweat rate although as you As your sweat rate does increase for the same person, you do tend to see small differences in sweat sodium concentration. So at lower sweat rates, so if someone's someone like myself, I'm I think 849 milligrams a litre of sweat sodium concentration based on our test. But if I was to do a
00:39:02
Speaker
a very cold, let's say a walk in a cold environment, my sweat rate was 100 milliliters an hour, my sweat sodium concentration would likely be lower than that. Oh, lower. Okay. And for example, if I was exercising at, you know, two and a half liters an hour, let's say in a very hot environment, my sweat sodium concentration might be a little bit higher. But the magnitude differences would probably wouldn't be very large. So we're talking for me at least going down to maybe 700 milligrams a litre up to 900 milligrams a litre. okay And so that doesn't really affect your strategy, but it does change slightly mainly due to the increased or reduced time that the sweat is in the sweat gland where it has available time to reclaim those electrolytes in the duct.
00:39:52
Speaker
Okay. I was going to ask you what the mechanism was, but there it is. Okay. Very cool. Um, you did. Uh, so, uh, we talked about, um, you know, replenishment strategies of fluids in terms of replenishment strategies for sodium. Do you just want to roughly match your, you if you happen to know your sweat, right? Because you did one of these tests, not, excuse me, not sweat, right. If you happen to know your sodium concentration because you did one of these tests, would you just.
00:40:17
Speaker
try to create a a sport drink with roughly that concentration of sodium in it? Yeah, generally. I think with anything related to health and performance, I think we always want to maintain, well, the body tries to maintain homeostasis. And so as soon as you start losing fluid or sodium or electrolytes, you want to generally try and replace those at a rate that matches your losses to a degree.
00:40:44
Speaker
and so that your body can maintain a degree of homeostasis and and therefore reduce fatigue and performance losses. right um and so yeah Generally, matching your sweat losses yeah sweat sodium losses in the concentration that you you lose them is is the best way to go about it. so If you lose around 1,000 milligrams a liter, replacing in your drinks, 1,000 milligrams a liter.
00:41:09
Speaker
Got it. Yeah, that makes sense. That's sort of what I've been, I've kind of been following and and advising folks to do. it It starts getting confusing. I think there's a few, few different, let's say there's a few different bits of information out there that sort of start referring to these things.
00:41:25
Speaker
in sodium loss in liters per hour. and of And it starts making things a bit bit confusing because that's not how we sweat sodium. yeah We sweat sodium in in ah in a per liter.
00:41:40
Speaker
um per litre of sweat loss rather than per litre per hour. And so when you start using these units, it it starts getting a little bit more confusing to what sort of amount and rate you need to be consuming sodium. And so the easiest way to think about these things is fluid volume liters per hour. And then sweat sodium concentration is in the relative sodium concentration of your drinks that you replace your sweat losses with. but And they are kind of independent of time.
00:42:10
Speaker
Yeah, I'm always a fan of of a simpler simpler solution. So I'm glad that it's no more complicated than at least you know estimating or or met having it measured and then trying to mix your your sport drink to the same concentration. That's it. um We won't get into carbohydrates, because we did that with Andy Blow. And folks, listen to that listen to those conversations. But um before we yeah before we wrap up, I do want to talk about, and maybe this is kind of i you know, getting into the territory of maybe a
Heat Acclimation Methods and Strategies
00:42:40
Speaker
follow-up. But I want to talk about mitigation strategies. So when you were talking about your climate chamber, you mentioned that folks can use it for yeah heat acclimation. What's the you know the state of the the science on the best approaches to
00:43:00
Speaker
maximizing your success if you know that your race is going to be hot. So we're recording this. It's early October. Kona's coming up at the end of the month. I'm not a hundred percent sure when we'll publish, but it'll be probably right around Kona. So it's a kind of a topic, a hot topic of conversation. For sure. I mean, there's, there's quite a few different things that we could talk about here. Um, the most effective mitigation strategy is kind of a training strategy, let's say, which we we've already touched on, which is heat acclimation. And so.
00:43:29
Speaker
One of the big risks we see in hot environments when you're racing is is just the impact on performance as well as the risk of extreme or exertional heat illness. okay And any associated other little illnesses there. um And so if you prepare yourself to race in the heat, you're doing that via some sort of heat acclamation, whether that's at home saunas or um hot water baths.
00:43:54
Speaker
They've been shown to be quite effective during doing the right type of passive heat acclimation, as well as the most effective version is a series of consecutive or close to consecutive doses of heat acclimation. Okay. So let's talk about dosage. and So when you're talking about consecutive, how long, how, you know, how hot, uh, is this passive? Is it active? I mean, give it, I mean, it it sounds like there's probably a pretty broad and you're also smiling listeners. so ah It's probably a pretty broad range of options there, but maybe give us ah one or two of your preferred approaches. For sure. So I mean, if we're talking about, it definitely can be both. So passive and active are effective.
00:44:33
Speaker
um ah The biggest thing to note with passive heat stress is that it needs to be done after exercise. So your body temperature already needs to be warm for it to be effective. um So if you're thinking about jumping in the sauna after a after a gym session or a run or a bike ride, that's perfect.
00:44:53
Speaker
Um, you just, you want to do the, do the sauna for at least sort of 30 to 40 minutes. Okay. So not necessarily can set like a full 30 to 40 minutes straight, but two, but two by 15 minutes, two by 20 minutes where you might step out for a minute or two to cool off and then jump back in. That's probably the best way to go about that one.
00:45:14
Speaker
Um, and it doesn't necessarily need to be more than that. A lot of the research shows, um, decent effects from 30 to 40 minutes post-exercise. And would this be for one week, uh, kind of every day of the week? What, what are we talking about in terms of like the, the sort of that cycle and microcycle?
00:45:32
Speaker
All of the heat acclimation research generally shows the requirement for some sort of build phase of heat adaptation. So you kind of need to do it for five days in a row, for example, for yourself to be allowed to build those adaptations quickly and effectively. So if you were to go once a week or twice a week for two weeks, it's probably not going to have the same effect as just going in for a week straight, if that makes sense.
00:46:01
Speaker
It does. And how far, let's say you're you're, you know, you're racing on a Sunday. How far in advance would you do this for optimal adaptation? I mean, you might be traveling and that might muck things up for you, but if you, you know, magic wand experiment over here, what would you do? Yeah, there's a few, there's a few different ways you can do it to do it the best. So for example, if you're turning up to Kona on, on, on Monday, so around a week before you, you generally want to have.
00:46:30
Speaker
your final dose of sort of any hot and stressful stuff, at least by Wednesday or Thursday, probably Wednesday, and then kind of rest up and try and rest up for the race. So you can't really turn up on Monday, jump out in the heat for three days and expect to be fine by Saturday. You really need to have done heat acclimation prior to getting there. And so one waving best practice situation would be you've done a week, two weeks, ideally, a week at a minimum, and then two weeks, um ideally, a few weeks before you turn up to Kona. look And so one of the big reasons for doing that is if you are able to get yourself heated acclimatized or acclimated,
00:47:17
Speaker
prior to going to a hot environment. And then you have a period of a week or two or three or four weeks even, where you're doing your normal training, you can focus on the mechanical load that you need to raise well, but also recover from that heat. And then when you go to a hot environment to race, having already done a block of heat acclimation, your re uptake of those adaptations you previously had, can be achieved within three or four days. Oh, cool. Okay, so you've sort of primed it. Yeah, you can prime the system as long as it's within, I think most of the research shows around four weeks is ideal, there's not much longer than that. But I'd expect you could get away with six to eight, especially if you've done a longer block of heat acclimation, right? um
00:48:01
Speaker
And so yeah, you can turn up on a Monday for Kona, go out and in the sun for two or three days, four days maybe, and then rest up and you'll be golden. Awesome. Okay. And so for those of us who don't have a sauna in their basement, if we're going to do the active approach, uh, what, uh, what would, uh, a protocol be for, let's say a week of, uh, active activation?
00:48:23
Speaker
Yeah, so I mean, the big thing with acclimation like this is, is you don't want to necessarily be doing it in your garage alone, because there is a safety component. And so it's all interesting. Yeah, because if you are turning on the haters, you're turning on a humidifier in your garage, it's your home trainer setup, potentially is the best way to do this, unless you've got a hot environment outdoors. And so one of the things people can do is turn on a heater, turn on humidifier, put on some clothes, these sorts of things. But We are talking about getting you hot and sweaty and there is increased risk of I guess, cardiac events and and you know, heat illness and all all these sort of extra things that you don't necessarily need to worry about when you're not trying to get yourself hot.
00:49:10
Speaker
um And so the biggest things that we talk about here are safety, so letting someone know where you're going, what you're doing, how long you'll be, um and also monitoring your body temperature to some degree if you can using some sort of device.
00:49:26
Speaker
would be ideal. um And so one of the ways we can control some of the safety aspect of this is controlling the exercise intensity. So if it is above 30 degrees, decently, hum decently, um decent humidity.
00:49:41
Speaker
one way you can control the exercise intensity is by using your own heart rate. And so targeting 75% of your maximum, okay, so you get yourself up there in about 10 to 15 minutes of a warm up, and then you hold yourself there and let yourself um spin down and you reduce the power to allow yourself to build that body temperature, build the heat, but then not get too hot. And so you reduce the power, but keep your heart rate up there. And then so if you're going through multiple sessions,
00:50:08
Speaker
um consecutively or close to consecutively, hopefully you'll see your power output remain higher for longer, come up at the same heart rate. And doing it like that means that your you're kind of self-regulating the effort and so you can build up the effort and build up the heat stress as you get fitter and fitter and fitter in the heat.
00:50:29
Speaker
No, that's really great. And that's ah it's a tool that we all have. I was going to follow up with a, let's say you have something like a a core sensor or some other you know commercial yeah body temperature device. um What are the recommendations for the for for those of us nerds who have one of those? Because I think I have one sitting around somewhere.
00:50:49
Speaker
Yeah, for sure. I mean, one of the big things there is is having the device on for at least 15 minutes before will be beneficial just to make sure that it's starting at the right temperature. Because if you throw it on after just sort of sitting there, sometimes it can read quite low if it's been sitting in cool air, okay which is entirely normal, let's say. It's just a, you know, it's a device that tries to measure these things. And if it's not measuring the right thing, yeah it might not give you the right data. So just taking, yeah.
00:51:18
Speaker
Taking care of it in the way of just putting it on and letting it get set up properly is the right way to go there. And in terms of the actual number that it gives, um generally with heat acclamation, higher is not better in terms of core body temperature. So if you're getting if you're consistently getting up to 39 or 39.5 or above,
00:51:42
Speaker
I would probably consider taking things a little bit easier okay because your recovery the next day will be um worse off. So when we're targeting um these body temperatures during sessions, we're looking for 38.5 to a maximum of 39 really by the end of the session.
00:52:00
Speaker
And if we're getting to 39, it's not ideal because you are getting a little bit too hot in some respects. And so certainly if you're getting to 39, five, I'd stop, I'd stop the trial. Yeah. Yeah. and stop this I mean, uh, I think everyone's tolerance as we've talked about is very different. I've never hit 39, five, but, and, uh, it's been a while since I wore my core device too. It's been a while since I've trained in any kind of structured way, but I remember hitting 39 and it feel like absolutely lousy. Like I was on the. on the limit of my heat tolerance at 39. And i I know that core temperature and perception of thermal comfort are not necessarily, well, they're they're probably correlated, but they're not necessarily the same thing, but I was miserable at 39. It wasn't an option to continue at that point, at least not in a recreational sense. What what environment, where what were you doing at that point at 39? Oh, I was just in my basement with clothes on.
00:52:52
Speaker
Ah, yeah yeah. Like all my therm, all my thermal, you know, winter cycling, living in, living in Canada, I got a very good stable of winter cycling clothes. And, uh, yeah, it was a lot of that stuff was on me at the time and it was, it was not very pleasant.
00:53:07
Speaker
That is another aspect of heat acclamation that I didn't touch on that has been shown to be effective. So if you use clothing like that, um you can use that in lieu of warm temperatures and it is quite effective. There was one study recently that showed I think of a 4% improvement in hemoglobin mass from doing that for 50 minutes a day, five days per week for five weeks.
00:53:32
Speaker
That sounds miserable. Absolutely miserable for five days, for five weeks. well Yeah. But imagine how good you'd feel. 4% hemoglobin mass is a lot though. so lot It's the same as what you see in altitude training for three weeks. Yeah, yeah. It's the it's the new al it's the new altitude training, right? that's what That's what folks would have us believe. Yeah, I mean, it kind of is. I mean, like if I can just hop on my bike, which is in in my background right here, and and do it in my basement without having to spend all the all the ah coin to go to a camp, I think is a pretty strong case to be made.
00:54:09
Speaker
Definitely. I think it's, I think it's quite promising. I mean, in the States, you guys have, well, not the States, sorry, Canada as well, North America, let's say, you guys have access to some high mountains and it's not so hard to get to just drive around and find some high mountains. But I mean, for me in Australia, it's just, there's, there's an option to go there, but it's really not that high. I think thread bow is at 1300 meters or so. So it's not quite enough.
00:54:33
Speaker
You're starting to get a little bit of an effect, I think, but not much. Yeah, it's it's not quite enough, I think, for a lot of people. And it's not close to any major city. So it's it's a six-hour drive from Sydney, for example. Oh, wow. OK. And then in Europe, you can do it. But it's you know it's reasonably expensive. And the dose is quite different, right? So if you think about the dose that you need for an altitude training dose, it's like your hypoxic dose is 14 hours a day for three weeks.
00:54:59
Speaker
Oh boy. Okay. Yeah, that's quite a bit, but that can be passive too, right? Is that just, I mean, we're, we're getting a little off, off topic here, but it's still interesting. It can be passive. That's for sure. But you've still got to be in that environment. So for example, if you're going to an altitude hotel, you need to be in that room, or if you're at altitude, you need to be up there the whole time. And then your training quality is impacted. For sure. Yeah. Whereas heat you could be doing it in 15 minutes, 50 minutes a day.
00:55:24
Speaker
five days a week. Um, and that's, that's at a high level. You could probably bring that down a little bit and see similar results. And interestingly, if you're not like to your point, if you're not really letting the matching going really high in terms of core temperature, the sort of the peripheral load is pretty minimal, right? Like you're not going to be tired or sore or anything from doing that kind of the kind of mechanical load you need to, to get those gains. So you might, you know, for those of us who, who have the time to do doubles can easily potentially still do some quality and, uh,
00:55:53
Speaker
in the the I'm just spitballing here, but in the and obviously not under those thermal conditions, but do some quality training under cool conditions at the same time. Yeah. So in that study in particular, those athletes combined that with their training. So they they did double sessions essentially, as well as doing their longer rides and runs on on the weekends when they weren't doing the heat sessions.
00:56:18
Speaker
Awesome. ah We talked a little bit about some mitigation strategies
Cooling Strategies and Psychological Benefits
00:56:22
Speaker
around training. What about in in race conditions? And again, you know i keeps I keep talking about Kona just because it's topical. what What do we think that some of the the more keen folks who are going on the island in three weeks' time are going to be doing to make the the most of their experience and keep it it as unhot as possible on race day?
00:56:45
Speaker
For sure. I think, I mean, one of the first things that you need to be doing right is getting your hydration strategy, right? So heating right fluid losses or fluid targets for your, your bike and run for this event is going to be more important as we touched on it gets warmer.
00:57:00
Speaker
the impact of dehydration increases so that's that's the first thing people need to be getting right yeah and then focusing on anything else outside of that is um a benefit let's say and so the biggest thing that we see having a big impact on performance and and even sweat loss actually reducing sweat loss is adding water to the skin surface so if you're on the bike and you pick up a um an extra bottle for example, what do you do with that bottle you could drink it, or you could order on yourself. And the same thing goes for when you're running.
00:57:35
Speaker
um One of the big strategies I'd recommend to my athletes is, um, making sure that whenever they pick up a cup of water to drink on the run, that they're also putting a cup of water on themselves to do two things. Firstly, um, it adds water to the skin surface to allow free evaporation. Obviously it's not going to be that free because it's kind of, it's very human. Yeah. So I was going to say, yeah, like I think, are we hitting the limit, especially on the run and of, uh, of evaporative heat transfer just from sweat, but it's hard to know.
00:58:07
Speaker
It's hard to know. It's kind of one thing is that it's probably providing some benefit and it's also probably replacing some of the sweat losses. And so if you can put some water back on the skin, it stops your sweat rate. It reduces your sweat rate slightly. Interesting. And therefore you need to sweat less and hydrate, rehydrate less. So those are the two big things there.
00:58:32
Speaker
And if you're not already at the limit of operative cooling, adding any additional water onto the skin surface should mean that you do help the body cool down slightly. right so The body always tries to maintain heat balance. It doesn't necessarily ever try and cool yourself down. It just does that naturally when you cease exercise or remove yourself from our environment back down to its resting temperature around 37. But if you're racing in the heat, you're kind of always at this this sort of steady state limit that you might be racing at 38.5, 39 for the entire race. But if you can add extra water to the body,
00:59:13
Speaker
you can potentially cool yourself down slightly, whether this is by a little bit of ice or a bit of extra water, any sort of additional exogenous cooling. is additional to what the body is trying to do. And therefore, it might bring the body temperature down, which would improve performance. And is there more an exogenous cooling in a second? But is there is there also a factor? I remember, what the heck was I reading? um Some study may have been of the recent study of the Omias headband. I'm not i I'm not exactly sure. But was there something too about
00:59:45
Speaker
the the perception of the cool liquid hitting your skin, like that the sort of the just a straight up psychological element of of having that coolness on your skin affecting performance.
00:59:58
Speaker
Yeah, it's certainly possible. I don't remember the exact bit of research you're talking about there potentially, but definitely if you can, any, any cooling effect that goes onto the skin, if that reduces the temperature of the skin, excuse me, that's generally beneficial for your perception as well as potentially performance because it will reduce main body temperature and it might reduce skin blood flow in that area as well, which will help bring some blood back to the core to allow you to use it for performance.
01:00:28
Speaker
Right. Very cool. Lindsay, you mentioned exogenous cooling sources and a shameless plug over here. ah There is a device that Endurance Innovation is is working on, um and we're ah we're probably not sure when you're listening to this, but we're going to try to time the release of these podcasts to coincide with our with our announcement of the device. so If you haven't already seen it, do do go check out our website at eitech dot.io on on the the new cooling device. But in case this comes out a little bit before, I'm not going to talk too too much about it. um But it is something that we're very excited about and we think is going to make a ah measurable difference in in performance, especially in races like Kona, where your typical cooling strategies may be a little bit blunted by the climate there.
01:01:19
Speaker
Lindsay, thank you so much for for taking the time. it's always It's always a pleasure to learn from folks. um And as I said earlier, one of the things I like about the the the outfit that you're with right now is how free you are with sharing the information that you have with the the wider world. It's exciting for me. I know that our listeners appreciate it as well. So thank you very much for your time. And I hope to talk to you soon. No worries. Thanks sir thanks at all. Thanks for having me, Michael. It's a great time.