Busting Myths About Riding in the Heat and Cold, with Dr. Stephen Cheung

At Fast Talk, we love a good myth. More than that, we like busting them. From the age-old myth about sleeping in a room with plants to the myth of lactic acid, Coach Connor and I enjoy applying science to firmly-held beliefs and turning worlds upside down—or at least correcting misinformation.

Today our focus is the large number of myths about riding and racing in the heat and cold. First, a reminder that we previously covered training in such conditions in episodes 21 and 35. While we’ll cover some of the physiology in this episode, check out those shows for a deeper dive into the mechanisms at play. Today, it’s all myths.

We start with some general myths about temperature: are there hot and cold riders? Good question. Then we move to myths about heat: Can you adapt? Does pouring water over your head help? And should your drink mix match your sweat? Finally, we tackle myths about the cold: Can you adapt to the cold? Should you over- or under-dress? Can you damage your lungs? That and much more.

Today, we’re joined by Dr. Stephen Cheung, a professor in the kinesiology department of Brock University in St. Catharines, Ontario. He is one of the world’s preeminent environmental physiologists and studies how humans perform in extreme conditions. He’s a well-respected author, the chief sports scientist at Baron Biosystems, makers of Xert, and he essentially tortures people as a job, which sounds pretty sadistic, and fun.

One other note before we get into it: in this time of online symposiums, Dr. Cheung is organizing a “Virtual Environmental Ergonomics” series. For more info, visit www.icee2021.com.

Today we’ll also hear from Nick Legan, Shimano’s road brand manager and a gravel racing expert, who has spent many an hour riding in extreme conditions, and Whitney Garcia, a former pro triathlete who raced in the heat of Kona and other hot climes throughout her career.

So, get your slushies, your bar mitts… your embro? No skip the embro. Let’s make you fast!

REFERENCES

Burdon, C. A., Hoon, M. W., Johnson, N. A., Chapman, P. G., & O’Connor, H. T. (2013). The effect of ice slushy ingestion and mouthwash on thermoregulation and endurance performance in the heat. Int J Sport Nutr Exerc Metab, 23(5), 458-469. doi: 10.1123/ijsnem.23.5.458
Cheung, S. S. (2010). Advanced environmental exercise physiology. Champaign, IL: Human Kinetics.
de Ruiter, C. J., Jones, D. A., Sargeant, A. J., & de Haan, A. (1999). Temperature effect on the rates of isometric force development and relaxation in the fresh and fatigued human adductor pollicis muscle. Exp Physiol, 84(6), 1137-1150. doi: 10.1017/s0958067099018953
Ferguson, S. A. H., Eves, N. D., Roy, B. D., Hodges, G. J., & Cheung, S. S. (2018). Effects of mild whole body hypothermia on self-paced exercise performance. J Appl Physiol (1985), 125(2), 479-485. doi: 10.1152/japplphysiol.01134.2017
Hou, T. T., Johnson, J. D., & Rall, J. A. (1992). EFFECT OF TEMPERATURE ON RELAXATION RATE AND CA2+, MG2+ DISSOCIATION RATES FROM PARVALBUMIN OF FROG-MUSCLE FIBERS. [Article]. Journal of Physiology-London, 449, 399-410.
Munoz, C. X., Carney, K. R., Schick, M. K., Coburn, J. W., Becker, A. J., & Judelson, D. A. (2012). Effects of oral rehydration and external cooling on physiology, perception, and performance in hot, dry climates. Scand J Med Sci Sports, 22(6), e115-124. doi: 10.1111/j.1600-0838.2012.01510.x
Nielsen, B., Hales, J. R., Strange, S., Christensen, N. J., Warberg, J., & Saltin, B. (1993). Human circulatory and thermoregulatory adaptations with heat acclimation and exercise in a hot, dry environment. J Physiol, 460, 467-485. doi: 10.1113/jphysiol.1993.sp019482
Oksa, J., Ducharme, M. B., & Rintamaki, H. (2002). Combined effect of repetitive work and cold on muscle function and fatigue. [Article]. Journal of Applied Physiology, 92(1), 354-361.
Oksa, J., Rintamaki, H., Makinen, T., Hassi, J., & Rusko, H. (1995). COOLING-INDUCED CHANGES IN MUSCULAR PERFORMANCE AND EMG ACTIVITY OF AGONIST AND ANTAGONIST MUSCLES. [Article]. Aviation Space and Environmental Medicine, 66(1), 26-31.
Oksa, J., Rintamaki, H., Makinen, T., Martikkala, V., & Rusko, H. (1996). EMG-activity and muscular performance of lower leg during stretch-shortening cycle after cooling. [Article]. Acta Physiologica Scandinavica, 157(1), 71-78. doi: 10.1046/j.1365-201X.1996.452172000.x
Racinais, S., Moussay, S., Nichols, D., Travers, G., Belfekih, T., Schumacher, Y. O., et al. (2019). Core temperature up to 41.5 masculineC during the UCI Road Cycling World Championships in the heat. Br J Sports Med, 53(7), 426-429. doi: 10.1136/bjsports-2018-099881
Rissanen, S., Oksa, J., Rintamaki, H., & Tokura, H. (1996). Effects of leg covering in humans on muscle activity and thermal responses in a cool environment. Eur J Appl Physiol Occup Physiol, 73(1-2), 163-168.
Scott, E. E., Hamilton, D. F., Wallace, R. J., Muir, A. Y., & Simpson, A. H. (2016). Increased risk of muscle tears below physiological temperature ranges. Bone Joint Res, 5(2), 61-65. doi: 10.1302/2046-3758.52.2000484

Episode Transcript

Chris Case 00:06

Hello, and welcome to Fast Talk your source for the science of cycling performance. I’m your host, Chris case. Here at Fast Talk we love good myth. More than that we like busting them from the age old myth about sleeping in a room with plants to the myth of lactic acid coach Connor and I enjoy applying science to firmly held beliefs and turning worlds upside down, or at least, correcting misinformation. Today, our focus has a large number of myths about riding and racing in the heat and cold. First, a reminder that we previously covered training in such conditions in episodes 21 and 35. While we’ll cover some of the physiology In this episode, check out those shows for a deeper dive into the mechanisms at play. Today, it’s all myths. We start with some general myths about temperature are their hot and cold writers. Good question. Then we move to myths about heat. Can you adapt? Does pouring water over your head help? And should your drink mix match your sweat? Finally, we tackle the myths about the cold. Can you adapt to the cold? Should you over or under dress? Can you damage your lungs that and much more. Today, we’re joined by Dr. Steven Chung, a professor in the kinesiology department of Brock University in St. catharines. Ontario, is one of the world’s preeminent environmental physiologists, and studies how humans perform in extreme conditions. He’s a well respected author, Chief sports scientist at Baron biosystems, makers of exert, and he essentially tortures people as a job, which sounds pretty sadistic and funny. One other note before we get into in this time of online symposiums Dr. Chung is organizing a virtual environmental ergonomics series. For more info, visit www.ic e 2020 one.com. Today we’ll also hear from Nick leagan. Shimano is road brand manager and a gravel racing expert who has spent many an hour riding in extreme conditions. We’ll also hear from Whitney Garcia, former pro triathlete who raced in the heat of Kona and other hot climbs throughout her career. So get your slushies, your bar mitts your embro? No, skip that, bro. Let’s make you fast.

Chris Case 02:37

Well, it’s been since Episode 38, believe it or not two years since we’ve had Dr. Stephen Chung on the program. So it’s great to have you back. I know you are a leading expert in environmental physiology. And that is a very interesting term in itself. So thank you for joining us. And please explain what that means.

Trevor Connor 02:57

I just want to point out you wrote one of the textbooks that a lot of schools around the world use for environmental extremes. So I mean, this is truly your area of expertise.

03:10

Yeah, first off, thanks for having me back, folks. And you’re right, Trevor I, I did write a graduate level textbook on environmental physiology. And I’m actually working on the second edition right now during this pandemic. But what is environmental physiology, it’s really looking at extreme environments, whether it’s cold, whether it’s he, whether it’s cold water, high altitude, microgravity, diving, air pollution, all of these things, and what impact that has on our ability to kind of perform as athletes or as workers. So the fun thing about the field is we get to really push our body to its limits, and that we get to really make an impact on everyday life, whether it’s population health, looking at global warming, and how we develop better heat policies, with different cities to working with Olympic athletes preparing for things like Tokyo or hot weather events. And also with workers. I’ve done a lot of work with everybody from firefighters to Ultra Deep miners, to Coast Guard, looking at search and rescue policy to try to make kind of work a lot safer also. So it’s a really fun interesting, both basic field and very applied field.

Chris Case 04:27

Yeah, it sounds amazing. And I bet at times you get to put people in extreme conditions in a laboratory setting which some would probably call torture, but I bet there’s rules against torturing people.

04:41

Yeah, there’s there’s an old saying in my lab that no one’s ever comfortable. If you’re comfortable with and we’re doing something wrong.

Trevor Connor 04:48

This you do a study where you had people shivering for 24 hours straight.

Chris Case 04:54

Yeah, it was. You mean mean person

Trevor Connor 04:58

had to bring that up.

05:00

But yeah, that was a study we did in 2010. That was a contract with the Coast Guard answer to rescue here in Canada looking at trying to simulate Arctic survival, we’re trying to look at, Can people sustain their shivering capacity for 24 hours, keep in mind that if you’re stranded up in the Arctic, it might take five to seven days to really rescue you. So all of the existing models were based on kind of two hour type long studies, which will be a really long kind of lab study. So we decided to really push the envelope and go for 24 hours, and they were eating survival rations, they had no water, they had no entertainment, except for a deck of cards. So it was pretty extreme. But it was, it was challenging to do, but I think it was really worthwhile in terms of the science we got out of it at the end.

Trevor Connor 05:50

So what names were they using to describe you by hour 23.

05:56

Both the participants and my lab members, they had all sorts of names for me, by the end, keep an email. Yeah, the participants were in there for 24 hours, we were in there for 40 plus hours as a team kind of from before the participants arrive to afterwards. So yeah, it was a it was a pretty challenging study. But again, it’s those are the kind of, you know, type two, kind of fun that you talk about afterwards.

Chris Case 06:22

It certainly speaks to your expertise in this in this niche of physiology, which we want to dive more into both on the cold side and the hot side. So maybe we should start with a brief, brief overview, a quick physiology lesson here, when it comes to temperature extremes.

06:44

Sure, well, I mean, what happens when you get hot is that you have a big competition for blood flow, you, you’re trying to keep cycling, you’re trying to send blood to your muscles, but at the same time, you’re getting very hot, both from the heat that you’re producing by exercising, and also because of the environment. So as a result, in addition to trying to send blood to your muscles, you’re also trying to send blood to your skin to get rid of heat by increasing the blood flow, trying to send more blood to the skin and also for the sweat glands to start sweating and eliminate heat that way. And you’re also shutting down a lot of other kind of non necessary or non critical systems like to your gut. So I’m sure we’ve had episodes before, where you’re talking about training the God and the impact of that. And so there’s a lot of systems at play. But ultimately, you know, instead of really being devoted to sending blood to your muscles, you are kind of having a lot of impaired blood flow to a lot of other systems too. So that’s what’s happened in heat. And then in the cold, the real challenge is trying to maintain heat in your body, instead of trying to get rid of it, you’re now trying to maintain heat. And the first thing the body does is try to protect the core, the torso and the brain. So the heart and the lungs and the brain itself, with the idea that you know, those are the systems you really need to live. So what becomes less critical is the muscles and so you have less blood flow going into the muscles, instead, your shunting or or restricting that blood back to the really vital organs to stay alive. So it’s kind of it all comes down. A lot of these reasons why we have impairment comes down to all these challenges in the priority for where the blood is going, as you are exercising, whether in the heat or in the cold.

Trevor Connor 08:56

So someday, I think you You are the one who told me this many years ago, but I really liked this image is to think, you know, we think of blood as a transporter. And you think of it as transporting oxygen, you think of it transporting nutrients, but it’s also a heat transporter. So if you are in hot weather, you want to get that blood up close to your skin, because it’s taking that heat from your core, getting up to the skin where it can get it out of your body. But in cold weather, it’s the exact opposite. You don’t want to lose any heat. So you keep all that blood close deep inside your body where the heat can’t really escape.

09:32

Yeah, absolutely. So you know, let’s say you’re writing along at 250 watts or 200 watts, you’re still producing the same amount of kind of heat within your body. But the challenge is that whether you’re in the hot or the cold, but if you’re in the heat, you are also having the external environment. So if you’re, you know, back in the old days in a tour of Qatar or in 2016, where the worlds were there Or every year and tore down under, you have, you know, a lot of extra heat. So not only are you trying to get rid of the heat that you’re producing in your body, but you are also having additional heat kind of dumped into your body by the environment. So you’ve kind of facing a double whammy, the main way the body responds is it, it is increasing a lot of blood flow to your skin. And to try to kind of get rid of that he kind of like a radiator, try to get it, get that warm blood out near the surface of the skin so that it can dissipate to the environment. And again, the other way is through sweating. So those are the big challenges that you’re trying to face again and Nicole, you’re still producing a lot of heat. And that’s what shivering is all about. So when we talked about can you shiver for 24 hours, that’s the body trying to maintain extra heat, even if you’re not exercising to keep your body at 37 degrees Celsius around 9697 98 degree Fahrenheit. So yeah, the blood plays a huge role as a kind of heat transporter throughout your body. In addition to to moving oxygen around, which is what we’re more interested in most of the time in terms of exercise, we’ve talked a bunch of times on the show about efficiency. And typically your average cyclist is somewhere 20 to 25% efficient, meaning that when they’re burning carbohydrates, when they’re burning fat, only 20 to 25% of that energy is actually going into the bike that other 75 to 80% is being lost as heat. But as you said, if you’re if you’re shivering, that heat is beneficial. Yeah, so I mean, he doesn’t kind of in that sense of waste product all the time. It is kind of a necessary part of life. It is again how homeo therms, like humans who are warm blooded maintain kind of a certain level of body temperature throughout. And what’s really fascinating about humans is that you know, from the day you’re born to the day you die, you know through kind of thick or thin whether you live in heat, hot environments, live in cold weather, you’re exercising, the body is just phenomenally capable of maintaining your body temperature within a really, really narrow range. And that’s one of the fascinating things that continues to kind of inspire me as I study is just how is the body able to do this? I mean, if you are running a marathon, the marathon de Saab? Yeah, versus if you are kind of stranded in the Arctic, for the large part, humans are still able to keep the body temperature really, really steady throughout the course of a day throughout the course of its life.

Trevor Connor 12:50

So we’re not gonna dive too deep into the the general physiology here because a we’ve actually already done two episodes on that. And I believe we have side interviews with you. Um, both of them. I know definitely on the cold weather one. Yeah, absolutely. Episode 21. We talked about managing heat. Episode 35, we talked about dealing with cold weather. I think that’s where I got my giant soapbox, because everybody knows my so I’m curious, like, when are you not on? So my biggest soapbox is people under dressing. And we will get to this and I’m excited. Um, but today, really what we want to dive into is all the myths about training and racing in both the heat and the cold. And I think there’s gonna be a lot of fun because there’s a lot a lot of myths out there. Where do we want to start? I guess you you sent us a kind of a general one. That might be a good starting point.

Chris Case 13:46

Yeah, I think we’re right at the top of the list is the question. Are there really hot weather in quotes or, quote, cold weather riders?

Trevor Connor 13:57

And before you answer that, remember, you are a Canadian, we are contractually obligated.

14:04

Yeah, yeah, absolutely. And that that’s the hilarious thing is how people’s kind of perception change. I was just being I was just an external examiner for a PhD from Australia, who was looking at the impact of kind of heat and ambient temperature on high intensity training. Basically, can you do intervals as hard and how does it impact it? And he and, you know, their their code condition that they claim was 13 degrees Celsius. And that the student was actually from, from Wisconsin, and I’m going man, your perspective has changed after four years in Australia, if you think 13 degrees Celsius is now cold. But yeah, so so to get back to whether they’re hot or cold weather writers, I think, ultimately, you know, we’ve seen examples of is, you know, enduring was Known for his love of heat and it was claimed he never performed well. And the the wealth of which was an April at the time because it was still cold and everything but yet he thrived in the heat. You have other guys who just really love the code, you got cyclocross racers who really love it, and it gets starts to get really below zero, below freezing. And so you get that wide range and and the big question is, is it physiological is a psychological or is it kind of cultural and I think it’s probably more of the psychological and the cultural then pure physiology. And cuz, you know, genetically in terms of our capacity to respond to heat or cold, we’re pretty similar, whether you’re born in a hot environment, or born in a cold environment, and grow up there. But But I think so much of it is cultural. I mean, if you are kind of a, you know, I was born in Hong Kong. So if I grown up there my whole life in a kind of a Southeast Asian tropical type climate, and I suddenly the first few years in Canada, I was young at the time, but I’m sure, I felt that was ridiculous. Whereas now, it’s not as much of a stress. So I think a lot of it is cultural. And it’s, it’s really hard to do those kind of cross sectional, kind of longitudinal type studies, because, you know, is it you know, is it a case of actual physiology? Or is it because, you know, way back early days, I had a really good race when it was boiling hot once. So now I think, Oh, I’m a hot weather writer, and I, I now kind of self select myself to become more of a hot weather writer and, and try not to write out as much in the code. And so I think a lot of it is that kind of cultural kind of stimulus, rather than any kind of ingrained Physiology or genetics. I know, for myself, I, you know, I don’t necessarily love the hot hot weather, but what really gets me is that part that’s just above freezing, where it’s a kind of a cold, winter day with a gale force wind blowing, and it’s kind of that gray skies, that’s probably my biggest Achilles heel, whereas when it’s well below freezing, you know, I I actually don’t mind it, I’m I go and ski and do all sorts of other stuff outdoors without complaining, but it’s those you know, there’s, I think everybody just has that built in experience. And I think it is comes to that it’s that experience that makes you more of a one type of writer or another.

Chris Case 17:49

Is there some truth to the fact that quote, unquote, circulation plays a role here, some people have better circulation, so blood stays in their extremities in their fingers and toes? If it’s a really cool day more than others? And so they feel it less? Or is there is that a myth as well? On Oh, that’s

18:12

definitely not a myth. We know from studies of, of people with frostbite injuries, that there are definitely racial differences. And the studies looking at kind of military and frostbite does show that particular kind of ethnic backgrounds, and particularly African Americans, and also individuals from the Caribbean, and also kind of somewhat intermediate, or would be Asians, that that have more propensity for frostbite compared to Caucasians. So there are definitely epidemiological studies showing that there are certain groups that are more at risk, and it does come down to differences in blood flow. And that’s actually in the hands and the toes. And that’s definitely one area of study that I kind of have done a lot in over my career and to show that there is definitely huge individual variability in terms of blood flow. And I think that’s where the discomfort really comes in, especially in the code is just trying to keep your hands cold or warm, and your feet warm. And I know if those go that, you know, all other bets are off I can have to warm is core on Earth, but if my hands and feet are cold, then you know, I don’t want to be outside anymore. So I think there definitely is a theme to that, that there are differences. And there are certain kind of physical syndromes such as Reynaud syndrome, where people have really, really strong almost aversive response and vasoconstriction or blood flow reduction in cold to the point that it’s intensely painful in addition to just being cold. So there is certainly differences across people. And so yes, there are different shades. But I think, in general, I don’t think we kind of start our cycling careers as a cold weather writer or a hot weather, I think a lot of it does become experience and self selection after a while.

Trevor Connor 20:26

Yeah, one thing I remember you had in your book that I found really fascinating that I didn’t know was me, we all know that when you get into cold weather, your body’s trying to preserve heat, so it’s going to shut up blood flow to your extremities, and that’s why your hands and feet get cold. But as I remember, this isn’t true for everybody. But for some people that actually cycles. So it’ll you’ll shut off blood flow to your extremities for maybe 10 minutes, 15 minutes, and then your body will actually let some blood flow, go to the extremities to warm up for a bit for 510 minutes, and then go back to shutting down blood flow.

21:03

Yeah, that process is called code induced faisel dilation. And it’s, you can really look at it, if you think about kind of the body as an engineering design that, you know, when you first get cold, again, you want to preserve the heat in your torso and in your head in your center of your body. So it’s the body is basically saying, Well, I can live without blood flow in my hands, I can live without my fingers in my hands, I can live without my lungs, and heart and brain. So that’s where I’m going to prioritize the blood. But it’s almost as if the body use can be hedging its bets saying, Well, I can live without my fingers. But I don’t really want to. So every so often is going to, you know, give my give my fingers a little bit of blood just to try to maintain kind of prolong the time before it does become damaged from frostbite. So that’s kind of the teleological kind of engineering design perspective. But, you know, again, a lot of the research, including a lot of work in my lab is trying to see, you know, how does that actually happen? What are the mechanisms actually controlling their finger blood flow in the code? But yeah, it’s, I know, I think we’ve all had that experience that we go out on a on a ride, where we maybe didn’t wear kind of the right amount of gloves, in terms of coverage. And then it’s cold to start with. But as you start exercising, you get warm, you kind of feel this almost like cyclical blood flow in your hands, you suddenly after about 10 minutes or so it starts feeling warm again, and then maybe it gets cooled and it feels warm again, and that’s kind of the that cyclic vasodilation going on in your fingers.

Trevor Connor 22:51

So this is another one that you sent us we So just to give our listeners some background, we said we want to do the the myth. So I emailed you and said send us the miss that you’d really like to cover. And what I love and you sent this is there is no bad weather, just bad clothing equipment. And before you answer that, I’m going to say I always do my homework for these episodes. And here’s my commitment. A week ago, I was up at 9000 feet. It was 36 degrees Fahrenheit, about two degrees Celsius, and it started pouring rain on me. And I had to descend for 30 minutes, I am going to make the argument that was pretty crappy weather.

Chris Case 23:36

It was not that there’s no such thing as bad weather. There’s just Trevor’s bad decisions.

Trevor Connor 23:42

That to

23:44

what I really said that a question to you, Trevor, so you can get back on your cold weather soapbox from 35 so I was anticipating I can just shut up and you can just be talking for an hour.

Chris Case 23:59

Let’s recap that. That’s not having to go on for an hour.

Trevor Connor 24:02

My recap is it drives me nuts. The number of people who underdress

24:10

Yeah, for sure. It’s Yeah, I know this past weekend up here in Ontario was first warm, kind of real weekend day and and and that was nice and warm. And that was the first ride I did without without arm warmers or knee warmers. And this is now early May. Whereas even in late April when it was not that far above freezing, I was seeing people in shorts and cycling and go like oh, god no, but yeah, no, I really don’t think there’s an excuse to be kind of barring catastrophe like what you just had Trevor but most of the time there’s just no reason to, to be kind of ill equipped for weather. We have gotten so much better in terms of clothing design nowadays. Whether it’s you know, more waterproof yet kind of really, really good fitting clothing to, you know, having gear on a bike, much better fenders and things like that, that, you know, most of the time, you can be protected a lot more from from cold. So I think we we have expanded our ability to really tolerate cold weather and not so much hot weather. But certainly, I think we’re more talking about cold weather here. And we just have so much nicer equipment than you know, when I started riding in the 80s, where there was no specialized cycling clothing, it was like a big kind of garbage bag type of rain jacket, those kind of things. So, yeah, I think people really need to learn how to dress properly for, for cycling, and I would agree with you, Trevor, it’s, you know, you, you almost never go wrong with wearing a bit more clothing than what you think you need, rather than then too little. And always have back up, if you can, most of the time. Unless it’s really, really middle of summer, I’ll still have you know, a lightweight vest stuffed in my jersey pocket just in case of you know, it’s suddenly getting cold or anything like that. So I think there is definitely cases of bad weather. But I think a lot of it comes down to our poor management of foreign gear and our clothing choices.

Trevor Connor 26:34

Particularly if you do layers, you can always take layers off, but you have to have them first. Yep. And what I always tell athletes is because I whenever I tell people, you need to dress more I always get the Yeah, but what happens if I’m overdressed? What happens if I overheat a little And my response is always if you are overdressed, you’re a little uncomfortable. If you are underdressed, you are doing damage?

26:59

Yeah, absolutely. It’s, I think that’s a good philosophy to have. And I think we’ll talk about later on about you know, whether things like embrocation and stuff actually works is a physiological or is it really just, you know, kind of making your skin tingle, and you are definitely at much greater risk in the cold with with your joints, were just aggravating little things that you know, in a normal temperature or when you’re warm, wouldn’t aggravate you. But those those things just add up when you’re cold. And, you know, go go start your car in the middle of winter, you know, it’s not overly happy. So, that’s like your body and before it really gets warmed up or if you’re underdressed that’s exactly the same thing that’s going on your joints. Yep.

Trevor Connor 27:50

And I agree with you completely about the equipment. I have always been somebody who’s dumb enough to go out and ride when it’s negative 20 degrees. And I don’t need to say Celsius or Fahrenheit. I think that’s the point where the same It’s cold. It’s really cold. And I can tell you 1520 years ago, it was miserable. Mm hmm. Now I have the battery operated heated socks heated gloves heated jersey guy

Chris Case 28:15

over here

Trevor Connor 28:16

and you have nice face covering you have better clothing, you can go out and out weather and actually be quite comfortable.

28:23

Yeah, well this this winter and I can’t believe as a thermal physiologist, and as a cyclist for 35 years it’s taken me this long I finally invested in a good quality battery operated and operated insoles and I got to set a bar mitts for my bike and cycle. Why didn’t I do

Trevor Connor 28:42

I know what took me 20 plus years to do this. I just did the bar mitzvah this year and you could go out riding below Chris’s lap.

28:53

laughing at these two Canadians talking pharmacists.

Trevor Connor 28:57

pharmacists are great. Like I’ve gone out when it’s below freezing, and I don’t need gloves on.

Chris Case 29:02

Yeah, no, I don’t discount their effectiveness. It’s just funny to hear you guys talk about it. That’s I, I tend to reach a point where I think the wind chill of riding around on my bike when it’s negative 20 is I mean, I’d rather do something else. Right. So yeah, that’s all.

Trevor Connor 29:24

I since we’re talking about the Canadian thing, I will actually back what you’re saying that it’s it’s more cultural, because I will tell you growing up in Canada, I hated the cold. I didn’t enjoy skiing. I loved it when our family went down to Florida in the middle of the winter, and it was warm. It wasn’t until I moved to the US and everybody started making fun of me for being Canadian. And then I went well, I’ve got to play up to stereotypes and now I have to like the cold and at first it was an act that a certain point I went, Wow.

Chris Case 29:52

I don’t mind the cold and yeah, you can totally convince yourself well, not everybody but you can certainly try to convince you Some people can do a good job of it. Some people might not be able to do as good a job of it. But if you just embrace those things, whether it’s cold, whether it’s heat, whether it’s wind, there is a complete component that is psychological there. And it’s it’s not unlike the, quote, hard man, moniker or label that gets placed on people from Belgium because they like to ride in the rain in the nasty weather in the spring classics, etc, you embrace that, it becomes a routine, and so forth. And that can help, I can certainly help.

Trevor Connor 30:36

It’s also proving make buyers point that there is nothing more Canadian than a Canadian living in the US. We sat down with former professional triathlete Whitney Garcia, who is racing the heat of Kona on several occasions, so well as many other Ironman events in hot environments. We actually originally asked her for her tips about racing in the heat and the cold. But she was quick to point out that there’s such a thing as a hot weather writer or cold weather writer, she likes to heat

Chris Case 31:08

as someone who raced in Kona, which is traditionally PR can get a pretty warm Yeah. What were your strategies for dealing with the heat in a race? So I got that hot and you were out there for so long.

31:24

One strategy was was mentally reminding myself that I was very durable, because I would way rather hands down race in a hot race than a cold race. I’m just that’s a again, a tendency. I hate being cold. It affects me mentally to be cold and hot. so uncomfortable, but I can totally deal with it. So I would even pick races that would be hotter. Definitely versus cooler, colder races, knowing that it could be a strength of mine because mentally I was like I can Outlast I can now sweat. A lot of people that are going to melt because he is a real detriment to some athletes who are excellent athletes.

Chris Case 32:01

you thrive on challenge. Yeah, yeah, but

32:03

I want but don’t challenge me with a cold race because

Chris Case 32:07

only certain challenges. I don’t know. Very specific channel.

32:10

I can. Yeah, I

32:11

mean, generally, yes, I thrive on challenge. But there are some things like yeah, cold isn’t a good challenge for me. So so were there any things that you did in terms of dealing with the heat on the day? Being well hydrated is huge. And so that’s reason why I still carry water bottle, water bottle everywhere I go even when I’m not to have it. It’s a total habit to

Trevor Connor 32:33

stay hydrated. Was it as simple as just carrying around a water bottle? Or did you use pre hydration mixes? Did you use ice drinks during the race? Or beforehand? beforehand?

32:44

Yes, I mean, your Yes, your hydration for a big race like that. And a hot race like that starts before the day of the race. So you’re just don’t let yourself get dehydrated. You are walking around with a water bottle and I would didn’t really need to be consuming ice. At that point. I mean ISIS during the race to keep your core temperature down. But hydration and then yes, there’s lots of different mixes of things to keep your keep your sodium levels and what other

Trevor Connor 33:12

other levels? Did you ever use them?

33:15

Yeah, there’s Yes. And those were usually recommended by my coach because I didn’t get really deep into the nutrition of things. But there was certain things that were helpful, I mean, just straight water. For a waste, you’re going to sweat and lose a lot of salt in Oh, salt tablets as well. I didn’t even know about that at all before of my coach to like take tablets of salt and potassium and whether like there’s a there’s good combinations of electrolytes and so that B also became part of the nutrition of the race. And sometimes like for Kona, and for some other hot tuned human races, you would start taking those a day before you just extra salt your food. You’re banking it

Chris Case 33:53

Yeah, basically

33:54

you’re like you’re like saturating your body with water absorbing capabilities as best you can. I don’t know how good that is for blood pressure.

Trevor Connor 34:06

That is a different conversation. Yeah,

Chris Case 34:08

that that well who said triathlons were good for you.

34:11

That’s great. Nothing reasonable. Then during the race ice is key and so are like in Kona, they have sponges. They’ll say that the AIDS aid stations will have soaked cold water sponges and so you put them on like the back of your neck there are some key places keep your head and your neck cooler has you liver he release a lot of heat from your head. So

Chris Case 34:30

I get that there must be both physically and very mentally beneficial.

34:35

This the cold spongy ice. Yeah, definitely. I mean, every aid station it’s like a it’s like a mile. Usually what they’re per mile like corner they were and it’s like you just knock it down. It’s just that that account where’s my sponge? It’s one mile away. We’re slowing while my ice pack? Yeah. So but you put them under your arm like under your arms. You stick them like in your uterus. So you stick especially sponges because they can be stuck places. Yeah. So really the points of that are going to help stay cool is your neck your head likes to get under your hat, under your armpits or near though that and you’re growing so you’d see people language sponges. The other thing about Iron Man is so not glamorous like on the whole it’s a political sport. So hardcore, but like the nitty gritty is so disgusting.

Chris Case 35:22

Yeah, people are probably pooping and peeing all over themselves shoving things in weird places, knows what they’re doing out there and Kona.

35:31

So no comment.

Chris Case 35:33

No comment. That means yes.

Trevor Connor 35:34

And cycling the version is I stockings which is you get women’s nylon? Ice in them? Uh huh. And then you put them down the back of your shirt. Oh, I never saw that. And so that that’s really big. And I so I was managing a team we are at Joe Martin in in Arkansas. And we also have red bikes in the quickest way to repair pink damage is just by

36:02

Neil Ha Ha Ha, ha, ha.

Trevor Connor 36:04

So I’m in the middle of Arkansas at this grocery store buying a box of pantyhose and red nails. And the person at the checkout counter looks at this, then looks over sees my shaved legs. Yes, like

36:19

interesting. That’s a good story. That is a good story. Lucky walked out of that grocery store.

Trevor Connor 36:29

I saw the look on her face. And I was about to explain them just like that’s why

36:35

I’m not even gonna try.

36:36

Yeah.

Chris Case 36:40

Perhaps perhaps we should flip the tables around and talk about something that the Canadians don’t know all that much about which is heat. Okay, and some myths about the heat? Should we go there?

Trevor Connor 36:52

Let’s go there. We got a better Why not?

Chris Case 36:53

All right. first big myth about or question about heat? can we adapt to heat? Dr. Chung?

37:03

Absolutely, it’s probably the best thing you can do to get ready for competing in the heat is to become physiologically well adapted. And the body’s capacity is immense in his field in. And I know if you’ve gone over in previous episodes, but just to recap, the big things that happen to your body is that your new thermal regulate better, your heart rate becomes generally lower at any particular outage. And also you sweat a lot more you sweat earlier, and you are much more sensitive in the sweating response. So you so for a given hour, you might go from say sweating out, you know half a liter at this exercise to almost one liter you can double the amount of sweat that you can produce. So there’s there’s an immense capacity there. And one of the big tricks is what’s the best way to do it? And should you do it by exercising in the heat, or Can I just go sit in sauna for an hour a day. And the best thing to do from both kind of a physiological perspective and also from a time efficiency is to is to train in the heat is to find some way to get your body hotter than normal. And the easiest way to do that is through exercise. If you are gradually, gradually adapting yourself in the heat, it might take about a week and a half to maybe two weeks to become really well adapted. And that’s one thing you can do if you are say, a triathlete and getting ready for Kona in November or late October no November but you’re it’s already cool in the place that you’re training in. Well, what can you do there, you know, you can go indoors and be on a stationary bike and maybe have less fans and normal because then you’re going to become your bodies can become hotter. The other thing you can do is you can wear a lot more clothing, and in trap more heat in your body as you are writing. So there’s a lot of kind of both low tech ways you can do the heat adapt, and also higher tech ways. So you can certainly go in use my environmental chamber in my lab and exercise for for a prolonged period of time every day. 60 to 90 minutes a day for two weeks, you can you know go to a hot environment early and for two weeks beforehand become gradually adapted. So there’s a wide range of things you can do. But the end result is you’re going to be better. You’re going to have a little bit more blood and plasma volume. So you can distribute that blood kind of you have more blood to distribute and your body is also better at distributing it and also getting rid of heat sweating. So those are the big things? And does it actually work? Which is the brass tacks thing. Besides the physiology? Absolutely. In a meta analysis that I co authored in 2016, we looked at about 96 different studies from the 50s, up to the present day. And we found about 48 studies that were actually had a performance test, overheat adaptation before and afterwards, and we found that 46 of them had a significant improvement, the mean was about 8%, improvements through two through two, ranging up to about 20% improvement in terms of performance, in terms of exercising in the heat. So absolutely, that’s one of the best things you can do. And whether you are a an athlete, or whether you’re a worker, that’s going to be kind of knowing that you’re going to be working in a hot environment is to get your body adapted to it.

Chris Case 41:01

When you say gradual over a week and a half, two weeks, what does that What does gradual mean? Is that a five degree temperature increase each time, or is that a one degree temperature increase each time? Or is it a length of time,

41:20

it’s more length of time, the main thing I mean, your body doesn’t really, in a sense, know whether you are becoming hot because you’re exercising or because you’re sitting in a sauna on a slate, all it knows is that it’s hot, and that you better become better able to deal with it. So the main thing you want to do is to raise your body temperature about one and a half degrees or so, as a as a general rule of thumb for about 60 to 90 minutes a day for about two weeks to get kind of an optimal level of adaptation. So for example, if you are going to a warm environment and you’re gone two weeks ahead, what that means is that you should knowing the first few days, you’re not going to be able to ride as long or as hard as possible, and get yourself adapted to it, it’s the same thing as without the two, you’re not going to go to an altitude camp and immediately start going into full race prep and race type intervals or insurance, you’re going to gradually adapt to it. And but by the time, after about two weeks, in general, the studies show that your performance can reach about the same level as kind of as if you were in a cooler environment after about two weeks in the heat. So I think that’s the next question we’re going to talk about is that, you know, okay, we see all these improvements over time, both physiology and performance after let’s say two weeks in the heat. Yeah. Does that become a benefit? If I’m going to go back and, and, you know, my main race is actually in the cool environment. So should I actually heat adapt to as an ergogenic aid for a competition in the in the code. And the analogy is, you know, that’s exactly why athletes use altitude training. They’re not necessarily competing up at high altitude, but they’re competing back and sea level, they’re using altitude to have all these physiological changes there, that is going to make them better when they compete a sea level. So does that hold for heat? And the scientific kind of consensus is really equivocal right now there, there are some very well done studies that show that if you heat become heat adapted, and these were in trained individuals, after two weeks, and then you went and competed did a time trial in the in a normal kind of cooler environment. Some studies show that you, you do have an improvement. And you can actually perform better after this period of heat adaptation, even if you’re competing in a cooler environment. And then there are other studies that don’t show it. So kind of the scientific evidence is almost split right down the middle right now. But I guess my personal take on it is yes, the performance benefits, it’s kind of a 5050 right now, in terms of where science thinks it is. But the main thing is, for the large part, there is no harm in being heat adapted. It’s not as if you are not going to be able to compete as well. If you are heat adapted, so at at worst case, it is going to be neutral to your performance at best case is going to improve your performance and in a cooler environment. So if you if you can do it if you can integrate it into your yearly training plan. And then I would say, why not? Why wouldn’t you because again, at worst, it’s not going to help you at best it is going to help you. And so I know when I’ve been advising different Olympic athletes, and even if they’re not competing in the cold, we’ve been working with their sports science team to really integrate kind of heat adaptation, you know, on the chance that it is going to have an improvement. And again, worst case, it’s not going to harm them. So as long as it doesn’t cost them extra recovery time, it doesn’t impair their kind of training capacity, then it’s kind of a good thing to have in your quiver, just in case it does work.

Trevor Connor 45:47

So the only thing I’ll bring up to all of this is just also remember that heat exhaustion is heat exhaustion, do be careful with all these different things, don’t think, Oh, I’m going to a hot event in the heat and need to heat it up. So what I’m going to do is go into my apartment or home or bedroom, whatever, close all the windows jack, the heat up to 95 degrees and do a six hour ride on the trainer. And that’s going to get me ready, right? That can fatigue you that can heat stress you so as you said you want to build up to this. And the example I actually think is back in 2008, they were really concerned about the China Olympics because of how hot it was going to be. And they did exactly that they took a lot of the hopefuls and put them had them do a five day train, I think was a five day training camp where they’re doing six hours a day and they put them inside a heated trailer and had them ride on the trainer

46:46

at a national team. You’re saying some of the hopeful writers,

Trevor Connor 46:49

okay. I know some of them. And we were in this and just said that was just about the most miserable experience of my life. It practically burnt me out.

Chris Case 46:57

Yeah, yeah.

46:58

Not any anything comes down to elite athletics. There’s so many different priorities at play. And, you know, heat adaptation isn’t the only thing that you’re concerned with. There’s so many other things. So you have to very carefully integrate into it. And the worst thing to do is oh, you know, I heard this podcast thing I should be heat adapted and do exactly what you just said, Trevor. And you really need to ease into it, you need to have a long term view of what is happening and you need to kind of gradually build up to it rather than just immediately jumping in with with both feet, so to speak.

Chris Case 47:36

Yeah. In terms of overdoing it. That brings up the next question, in a way, do we shut down if our body temperature gets too high? Is there some protection built into our physiology? So?

Trevor Connor 47:51

And before you answer this, I have remembered reading, that there is a temperature where literally our bodies just shut down. As a matter of fact, there’s this older study that I’m looking at right now in the Journal of physiology for 1993. Where they said basically all the athletes they tested as soon as their core temperature hit 39.7. They, they all shut down.

48:17

Yeah, though, that was a classic study by Budo Nielsen in 93, from Copenhagen and, and that was actually also some work that I followed up with in for my PhD in Toronto at the military lab where we found the same thing we found that individuals, whether they were heated, adapted or not, whether they were well hydrated or dehydrated, they they seem to have a very consistent temperature at which they voluntarily stopped exercising, we, we asked them to keep walking, they were wearing chemical warfare clothing with the Canadian Forces, until they just weren’t willing to do it anymore. And we found regardless of hydration or acclamation status, there was a very consistent core temperature and this led to my paper in 98. And that between those two papers really instigated this whole idea that there was a critical internal temperature which our body shuts down. And, and there’s been a lot of controversy about it since and we can talk about it a little bit coming up. But uh, but the main thing is, do we shut down if our body temperature gets too high? Absolutely. You can’t fool kind of physiology in a sense. At a certain temperature your proteins are in your cells are just going to start breaking down. It is what happens when you cook an egg. Right, the protein changes shape and changes form. So the proteins in your body are no different. They’re optimized for working within a well within a very narrow range of temperatures and if it gets too high and again, I’m using Celsius here, because I’m Canadian. So you know, between 4041 and 42 degrees Celsius, that protein starts breaking down in your body. And that’s where you have irreversible damage to yourself. So there is an absolute limit, which you can’t go beyond. Now, the body has this thing called the brain, which is designed to ideally never allow you to get to that catastrophic point. So that’s where you start sensing, I’m really uncomfortable, I feel really hot. And you know, I’m, I’m not really having that much fun anymore, maybe I’m going to slow down, or maybe I’m going to stop. So your brain is your body’s best defense against kind of your, your physiology, or you taking yourself to that catastrophic limit. So that’s where in the early 2000s, as a response to this kind of critical internal temperature model, Tim Noakes in South Africa came up with this central governor idea of really where it’s your brain that is controlling your, your body and how hard it is willing to exercise. So the analogy I personally like to use it’s, it’s, you know, kind of your temperature system is kind of like a gas gauge, like your gas tank, eventually, you’re going to run out of out of gas, right. But before that happens, you start seeing this yellow warning light on your dashboard. And you know, where your brain comes in is really the comfort level of what you feel about driving with your yellow gas gauge light on, some people will immediately say, No, no, no, this is the end of the world, I need to find the next gas station now. Whereas other people are saying, Yeah, no, I mean, it’s still good, I can still keep driving for another, you know, whatever. You know, 30 minutes or whatever, it’s no big deal. And so that’s where your brain really comes in, you want your brain is trying to protect you ultimately, from running out of gas, but it’s trying to tell you in terms of temperature, in terms of your kind of substrate availability, how much kind of glucose and glycogen you have left in your body, how hard you’re breathing, all of these are signals telling your body How close are you to this catastrophic limit? And how hard Are you willing to, to kind of edge up to that line without going over? So you know, long answer to your question is that, yes, there is an absolute physical limit that you cannot go beyond. But most of the time, we’re well below that limit, because our brain is, is telling us, you know, telling us to slow down telling us to take a break, take a drink of water, whatever, all of these things to try to protect ourselves. And the best defense is the brain telling us Let’s slow down a bit.

Trevor Connor 53:02

It’s good to hear how the brain supposed to work is when that yellow light goes on. That’s my brains like, ooh, we’re having fun now.

Chris Case 53:11

Captain of bad decision.

Trevor Connor 53:13

What’s your feeling about this 2019 study looking at the 2016 UCI World Championships where they showed two of the women on the winning ttt team hit 41.5.