INTRO TO RACING IN HOT, MISERABLE CONDITIONS
BASICS OF THERMOREGULATION
DIALOGUE WITH MYSELF
COOLING THE BRAIN AND SPINE
ED BURKE'S ICE BAK STUDY
COOLING THE SKIN
COOLING THE STOMACH
CONCLUSION
THE SCIENCE (AN ADDENDUM)
INTRO TO RACING IN HOT, MISERABLE CONDITIONS
I wrote an article a year and a half ago on cadence. In it I said, "Some things you just know." It doesn't take a degree in physiology to know that the hotter and more humid it is outside, the higher your pulse and the slower you go. Five years of life science classes in college didn't teach me this. A heart rate monitor, a wristwatch and a pair of running shoes taught me this. You've learned it, too, and you didn't need an expert to teach you.
Amazingly––to me––there is little combat gear for the multisport athlete that allows him or her to beat the heat, and what is sold is not specifically marketed for that purpose. Water-filled bladders are generally sold for and described as ways to beat dehydration. But I think companies like Camelback and Ultimate Direction are missing an opportunity to sell their products as speed weapons. Perhaps these companies see the opportunity but aren't getting their message across. We'll help form that message a bit in this series.
My wife JulieAnne had done several ultras in 1992, more than she should've. (My shortsighted coaching was to blame.) She'd just gone 9:08 in winning IM Canada so she was in shape, but Kona was only five weeks away. She also had IM New Zealand, IM Germany and Nice in her legs from earlier in the year.
Heat is the worst thing to have to face when you're already heavily trained and raced. But we were lucky. A company whose name I've long forgotten and whose product came and went with barely a notice was in Hawaii that year. They made a sort of bandana that had in it some substance that stayed cold. You only had to wet it occasionally. I told Julie to keep this thing tied around her neck and to make sure to re-wet it at aid stations.
She remained quite comfortable throughout the race and came home in 9:21, in second place in the women's division. I sure wish we'd had that product the next year, when Julie overheated during the race and was rushed to the hospital in Kona for surgery that would result in the removal of half her large intestine.
Kona's heat and humidity make IM Hawaii different than any Ironman except those held in similar weather conditions. It makes super performers mortal. It requires a special kind of athlete who has the ability to regulate heat better than others. But there may be an alternative, or at least a mitigator. Are there ways to keep your body cool throughout the race? We'll explore various options over the next few days which will require some thinking outside the box and perhaps result in some enterprising company making products that are not yet in existence.
Our purpose in writing this article now is that every year I and others I know think about this subject, mull over what sort of products might be made to limit the effects of heat, and we never do anything about it. Then, when we're over in Hawaii and baking under the sun, somebody says, "Dang, why didn't we make that thing we were talking about a few weeks earlier at Interbike?!"
With Kona still two weeks off, perhaps we can discuss some options so that at a minimum we might spark a thought in those of you who're heading over to race.
DIALOGUE WITH MYSELF
As expected, I awoke the morning after writing my intro to thermoregulation and, voila, my in-box contained several references to different companies that make the cool bandanas I wrote about. One such product is called Chillers, and another is Coolbandana.
If you want to find out anything, just ask Slowtwitch readers. I'm tempted to ask about the current location of Osama bin Laden––judging from my experience there's a Slowtwitch reader with the answer.
Which areas of the body would you want to keep cool during a hot day? I’m simply applying intuition to this, and my list is not based on hard study. The list is not obvious when you think about it because, in turning the question around, what are those parts of the body not sensitive to heat? Which body part is unessential to keep cool?
That term we always hear used is “core temperature.” It’s necessary to keep one’s “core temperature” down. But what’s the core? Is it inside the rib cage? Everything inside the torso? Everything below the epidermal layers? Using any of those definitions gives us a lot of stuff to keep cool and doesn't narrow it down much.
What about the spine, and the brain? Is that part of the "core?" I’d suspect it's important to keep neural tissue cool––especially the brain––because so much that is dependent on endocrine function begins up there. Add to that the admonition that a fever is dangerous over a certain limit––say, 105 degrees F––because it may cause brain damage. That says to me that the brain is pretty susceptible to heat. Then there’s the fact that it’s just damned uncomfortable to have a hot brain.
But let’s say I make my priorities the brain and the spine, and secondarily the stomach. My list includes the stomach because of another of my assumptions. I like the idea of keeping the stomach cool because I have a suspicion that stomach contents absorb faster when they’re below a certain temperature. For everyone in the industry that says I’m right about this, though, two say I’m wrong.
Finally, what is the best way to keep the brain, or the stomach, or the heart, or the major skeletal muscles, cool? One obvious way is the way the body naturally cools itself: evaporation of sweat.
My intuitive attempt at organizing these random ideas into a structure yields three questions:
- Which body parts do we most urgently want to cool?
- Which body parts are we able to most easily cool?
- What approaches or techniques can one employ?
My answer to the first question is: brain, spine, stomach, and skin. I give priority to these areas because:
- I’m making the assumption––which may or may not be valid––that neural centers are a high priority.
- In answering question number two, it appears that neural centers are “available” as they’re reasonably close to the skin.
- I’m assuming that keeping the stomach cool helps absorption, and again it meets the criteria of question two in that it’s accessible.
- As for the skin, it’s obviously accessible, and it’s also the key to keeping the entire body cool.
That leaves question three to be considered. How do you keep the brain and the spine cool? There are two ways I can think of:
- Externally cover it with a cool substance
- Cool the blood as it passes by on the way to the area to be cooled.
In my next installment I'll throw out some suggestions. Perhaps there are effective (if oddball) ways to keep the brain and spine cool.
COOLING THE BRAIN AND SPINE
Two views on this. One, that you try to cool the blood which travels through the largest vessels passing close to the skin (for example, the carotid arteries). Two, that you try to cool the spine and brain topically, by putting cooling agents adjacent to the spine and head.
Cooling the brain and spine appears to yield two possible benefits. Of course you cool both of these organs, but secondarily a lot of blood passes through the brain. At rest the brain is the body's biggest user of both oxygen and glucose, and since blood is the delivery system for both, ipso facto it also it receives an extraordinarily large amount of blood. Every minute 25 percent of the body's blood passes through the carotid/jugular passages.
Add to that the fact that your body works not unlike a car's engine. Blood replaces water (and anti-freeze) as the cooling agent. If we can keep the blood cool, we win half the battle of keeping the body cool.
The question is, is it really possible to cool the blood as it travels through the carotid and jugular passages, such as via the bandana mentioned above? Experts I've spoken to are split on this. There may, however, be alternative––or additional––measures one can take that will work toward the same goal. Yes, a lot of blood passes through major veins and arteries close to the skin at strategic points––at the neck, the armpits, the groin, and the sternum, for example. At the same time, a lot of blood passes through heavily capillarized areas, like on top of the skull. So if you're not able to easily get at the blood as it drives down one major freeway, maybe you can get at it as it negotiates a lot of different sidestreets.
After having written all of the above, I do notice that none of it is of any practical use, so let me turn my attention to implementation. As regards cooling the spine––and whatever blood may pass up and down the center of the back––I have news both good and bad to report. The good news is that there is something you can do that appears to produce demonstrable results.
I was at Spencer Smith's house yesterday, working on some bike positioning with him as he gets ready for Ironman Florida and we were talking about heat management. "Have you thought about wearing a Camelbak during at least the ride?" I asked him.
"Absolutely not. No way I'll ride with a thing like that weighing me down."
That is exactly what I'd have said a year ago, and the great majority of pros would say the same thing. I would not say this anymore. With help from the folks at Camelbak I've done my own anecdotal experiments (is "anecdotal experiment" an oxymoron?) and I'm convinced that a Camelbak is an efficacious thermoregulatory device. I'm not the only one who thinks so, and there is at least one expert who has evidence that is more than anecdotal.
Dr. Edmund Burke––well known in the cycling community for doing a lot of testing––has specifically tested this particular use for Camelbaks. "It does cool the body's core temperature," he told me, "And I've published this. This test was done in a controlled setting, in a lab."
His results were published in Cycling Science, which is now out of publication. I've got every edition of this publication in a box set somewhere. (I can't find it.) Dr. Burke has promised to email me the test, and when I get it Slowtwitch readers will get it.
Here's the bad news. Camelbak has stopped producing the units that were most useful for thermoregulatory purposes. It first made a product called the Ice Bak, which was an extremely spare unit that was designed to allow the ice or cold-water-filled bladder to rest adjacent to the spine. It was replaced by the Razor, and this will not be sold after 2001. What enthusiasts used to do with these units was fill them up water and freeze them prior to use, or fill them with ice cubes and freeze them, only adding water shortly before the event. The ice would slowly melt, providing cold water for drinking, and the Ice Bak or Razor would keep the spine cool during the event. My advice: Find a retailer who still has a Razor and buy it.
Another possible iteration of this sort of technique would be a skinsuit manufactured with a pocket just for the insertion of a Camelbak (or Ultimate Direction, or similar) bladder. There would be practical problems with this (at least for triathletes). One would have to be able to easily insert a bladder into the skinsuit "bladder pocket" after the swim––I doubt anyone would want to swim with the bladder pre-installed––and it might not be easy to get the bladder into its skinsuit (or singlet or jersey) pocket. Then there is the issue of routing the drinking tube. It would clearly be better if someone––CamelBak, Ultimate Direction, or other––would make a product that would serve this function, and stay with the product long enough for the message to gain traction among the end-user audience. (CamelBak had the right idea with the Ice Bak and Razor, it just ran out of time waiting for the buying audience––and magazines, like this one––to come along and champion its product.)
What about cooling the head? When I resumed racing this year for the first time in a decade, I chose a race––Wildflower Triathlon––that is quite long and hot. I had a small lunch-sized cooler sitting in my transition spot that had a simple water bottle packed in ice, and when I finished the bike ride I strapped a water bottle carrier around my waist and had cold water for the first three or four of the 13 miles I was to run.
I believe I'll expand on this idea next year, perhaps––unless I procrastinate past the point of utility––by replacing the bottle in my mini ice-chest with a "frozen hat." In my mind's eye I'm thinking about that Coolbandana. If one were to sew the ends together it would make a ring. If elastic was used to sew the ends together (or some other form of adjusting the circumference), it would fit a variety of hat sizes. Then imagine a bill on one side, and perhaps a Sahara-style flap on the back side.
Inside the ring one might choose to sew in an enclosing top. It could be sewn either on the top or bottom of the bandana's one-inch-thick ring (which has the gel-filled corpuscles inside––the agent that stays cool). If the fabric was sewn in adjacent to the bottom of the ring, then the ring would act as a trap to keep in ice that could be thrown inside it (when one passed an aid station). But in this case would the ice dance around inside the ring on top of one's head? That might be nerve-wracking (pardon the pun). The ice also might fly out. If the fabric was sewn across the top of the ring it might make a convenient place to trap ice––if you, let us say, scooped ice into your hat as you passed by an aid station.
Obviously I'm just running with an idea here (not a completed hat), and I'll leave it to other enterprising souls to flesh out and execute this. Maybe a sponge could be sewn into the top of a painter's hat so water could be collected, delivered, and "stored" on one's head while passing each aid station. Maybe a hat could be made in which the gel-filled corpuscles were sewn in quilt-style, so that they were evenly distributed throughout the hat.
I don't know the answer, but it would certainly be nice if there were some options when next season rolls around.
COOLING THE SKIN
In the 1997 Race Across America, one competitor––Gerry Tatrai––had a unique method of keeping cool. It involved the use of his following vehicle. Every RAAM competitor has a support crew that follows him or her in a vehicle—nowadays, it's usually an RV. The support vehicle drives directly behind its rider.
Tatrai's following RV was equipped with a long pole that extended forward past and above Tatrai, spraying a mist on him as he rode. Some of the other riders responded with indignance mixed with grudging admiration, and most were prepared to emulate Tatrai the following year. It wasn't until one or more of the competitors pointed out the offending section in California's vehicle code that race director Michael Shermer decided to ban the moving shower.
As has been noted in our thermoregulation primer, there is more than one way for the body to cool itself. In each of these ways the application of cold water on the skin will help, and Tatrai was ingenious enough to conceive a way to exploit this physiological truism.
This begs the question: What could be done to achieve a similar result in a triathlon? Just because nothing’s been attempted yet doesn’t mean a solution isn’t out there.
One idea is to extrapolate Tatrai’s idea further––to take with you your own personal misting system. Obviously, you must take it on the bike––if it’s the cycling leg you’re considering––and that includes taking the reservoir of water. Perhaps in a long race, though, it’s not necessary to take all your water with you, since they’re probably handing off bottles of water during the event.
My “invention” is just a rethinking of the handlebar-mounted water bottle (e.g., Aerodrink, Jetstream). What if, for example, the plastic drink tube on your favorite drinking system was replaced with something not unlike the “gun” that comes on top of a bottle of liquid household cleanser? When you want a drink, you adjust the nozzle to spray a stream of water toward (and hopefully into) your mouth. Adjust the nozzle to “mist” and pull the “trigger” when you want to cool your face, or look toward the ground and give your head a misting through the vent holes of your helmet.
Obviously there are problems with this. You can only use plain water with this scheme. You’ve got to get your solutes through a gel or via a separate water bottle mounted on your bike. And you can’t wear sunglasses while misting your face.
None of these are serious problems for me. I don’t wear sunglasses during a race anyway, because I long ago grew tired of having to cleam the drops of sweat off the inside of the lens. As for solutes, there are lots of ways to take in electrolutes and fuel.
Here’s another idea, both for the run and the ride. What about a new style of cap for bicycle water bottles? Right now when the pull-top caps are in the “down” position, no water comes out. What if while in this position the rider (or runner, if he’s carrying a bottle) could squirt a mist or a wider, finer spray of water while the cap is “closed” and release a stream of water when it’s open? Better yet, a cap that features two “clicks”––the first for mist, the second for stream. I’m also thinking about what might offer more utility than the bite valve for Camelbaks and similar drink systems.
This sort of idea seems to me to have plenty of utility, but will it actually serve to cool the body to a greater degree? I don't know. There are three options. The first two are that the idea will work or that it won't. The third is that it may not cool the body temperature but might simply make the user feel better, and that this might spur him or her on to a better performance. I believe Burke touches on this in the attached Camelbak study.
COOLING THE STOMACH
There is controversy about this. Two-thirds of the doctors and sports physiologists with whom I've spoken say that there is no practical benefit to sending cold versus room-temperature water down the throat. This is because, they say, whatever goes down soon attains the temperature of the "soup."
Others disagree, saying that there is demonstrable evidence of the converse. I've just never seen the demonstrable demonstrated––in fact I've not seen good scientific evidence presented to definitively support either side.
What would the value be in cooling the stomach? Aside from the fact that colder water is more comfortable to drink, perhaps colder fluids may keep the stomach contents from rising to a temperature that inhibits stomach empyting.
This raises a slew of questions. Is stomach emptying at all temperature related? If so, the temperature of what––the contents of the stomach itself? Of the core temperature in general? And if the stomach "turns off" due to a high temperature, is it because of the stomach temperature itself, or the accompanying high workload under which the body is placed?
I don't know the answer to any of these questions. But I do know a few things. One ought not to underestimate the psychological effect of drinking colder fluids versus those at room temp. I'm using the term "psychological" loosely and am throwing into its basket issues such as comfort and pain abatement. It is apparent that the onset and duration of pain is an inhibitor to performance. Powerful pain relievers such as morphine have long been banned from competition, yet are still used illicitly. Some athletes today continue to race using legal pain relievers such as ibuprofen (whether or not this is a good idea, as is debated in our article on race fueling). Simpler yet, just consider racing on a comfortable versus ill-fitting saddle. The pain in the butt you get from riding will certainly cause a performance decrease, even though it has nothing directly to do with the physiology of performance.
To the degree, then, that cold water applied topically and consumed internally is a pain abater, it's going to make you race faster.
It also seems intuitive that ingesting cold fluids is noticable to the stomach. As many Slowtwitch readers know, our family consists of two "parents" and a gaggle of dogs. We've noticed that several of our dogs are susceptible to the effects of ice water. If they drink much of it after a hard exertion you can bet that several minutes later everything will come back up. This is not just a canine phenomenon. We have human family members that suffer the same malady. The fact that this occurs minutes after ice water ingestion makes me suspect that it is the pronounced change stomach contents' temperature that is to blame, rather than some form of reflexive response to cold water passing down the throat. To me, then, the intuitive conclusion is that cold fluids do act to cool the stomach's contents, if only for several minutes.
It has also been demonstrated––though just anecdotally––that the stomach will often "shut off" during long, hot-weather races. Those of us who've followed Hawaii Ironman racing for many years can all relate the same stories of pro racers who continued to eat and drink on schedule but whose stomachs just expanded, absorbing nothing. What causes the stomach to decide not to cooperate? There are several possible culprits. One might be tempted to blame the well-established shunting of blood under exertion to other, temporarily more important, areas of the body. Perhaps such athletes simply misjudge their pace and their heart rates rise to a level that inhibits gastric emptying. Another culprit may be the osmotic potential in the stomach––too much solute, not enough solvent. Related to this might be the choice of food in the evening prior and morning before the race––the contents of which are still hanging around, inhibiting uptake.
All that noted, there are seasoned pros who will tell you that, in their experience, stomach temperature plays a big part.
It is difficult to determine just why a person might stop absorbing, but while the causes might be unrelated to stomach contents' temperature, I cannot see a downside to cooling off the stomach. What is the strategy for ensuring that what one drinks during competition is always cold?
One way is to use a Camelbak or equivalent. Users will frequently ready their Camebak's bladder the night before by packing it full of ice cubes and keeping it in the freezer, filling the remaining capacity with fluid the morning of the race.
Another tactic is to make liberal use of bicycle aid station water as opposed to carrying all your fluids with you from the start. Various methods have been employed to create a fluid replacement mixture on the fly, most of which utilize a refillable handlebar bottle.
One way to ensure cold water on the run is to keep one or two bottles of ice and water in a small, lunch-sized cooler at your aid station spot, putting the bottle(s) into a water bottle belt for the run. It's the poor man's Camelbak.
I've also wondered about devices one would put into water bottles. We've all seen hard rectangular packs that one freezes and that stay cold for many hours thereafter. What if they were made in smaller sizes that were perfect for water bottles? Might one be able to use these for regular bicycle water bottles, which when carried on the run could be refilled at aid stations, allowing the water to remain cold throughout the run? It is also worth mentioning to those who just can't see themselves running with a Camelbak––but who do run with water belts––that bladder-style water carriers also exist that are waist-mounted.
CONCLUSION
My point in this series was to raise a discussion. Neither endurance sports in general nor triathlon in particular has taken a hard look at thermoregulation. We know a lot about what ought to go into our stomachs, but little about what temperature it ought to go in at. We dearly wish to escape the heat, and to cool our bodies, during a long, hot race, but how well do we prepare for that inevitability prior to the event?
The knowledge that thermoregulation is important has been out there for years among practitioners. A decade before Gerry Tatrai's support team rigged their moving shower, RAAM riders' teams would all carry Hudson sprayers to shower their charges on the fly. Why haven't we done more to make thermoregulation as integral a part of our racing protocol as electrolyte replacement or aerodynamics?
I think Camelbak tried to do so a decade ago, but while its message about hydration got out, the message on thermoregulation did not, and it has abandoned products in its line that specifically attacked this problem.
Long-distance triathletes represent a bit more of a market than the sub-group of a sub-group, which was the case with RAAM riders. Perhaps now is the time for enterprising manufacturers to start to take a look at helping solve this problem.
THERMOREGULATION––THE SCIENCE
I received an email from an exercise physiologist friend of mine, and it reads as follows:
"At the risk of stepping on your toes (like I haven't done THAT before!), I have to say that I found the recent series of articles on thermoregulation to be very disappointing. This may be the single most researched area within the field of exercise physiology, and in fact much, much more is known than you repeatedly implied. It is unfortunate that you did not consult with one of the well-respected investigators in this area (not me - my "thing" is metabolism) before embarking on the series. If you had, I think you would have presented a number of points quite, e.g., the effectiveness (or lack thereof) of spraying water on the skin during exercise (doesn't really help), the optimal temperature of fluid replacement beverages, etc. Don't just take my word for it, though...surf on over to PubMed, enter the keywords "thermoregulation" and "exercise", and see how many scientific studies pop up ( I get 1,488)."
My friend is absolutely right, there is a huge number of citations on the subject of thermoregulation and exercise. As for searching PubMed, been-there, done-that. Almost all of it refers, however, to what thermoregulation means to performance, i.e., "When you're hot, you go slower." Or it refers to the effect of proper hydration on thermoregulation. Or what percent-solution to use. Or whether full-body cooling prior to exercise makes one less susceptible to the heat. Almost none of it (incredibly, to me) measures the effect of fluid temperature on gastric emptying. Two of those 1,488 (to the best of my ability to search) refer to the effect of spraying water on the skin. I thought I'd offer a redux on what I found.
On the subject of thermoregulation by way of cooling the skin, here is what I am aware of on cooling the head:
• European Journal of Applied Physiology, January, 2000, Desruelle AV, Candas V., Thermoregulatory effects of three different types of head cooling in humans during a mild hyperthermia, in which they report that, "These results suggest that head skin cooling causes a reduction in heat strain."
• Ann Physiol Anthropol November, November, 1993, Watanuki S., Faculty of Science of Living, Osaka City University. Effects of head cooling on cardiovascular and body temperature responses during submaximal exercise. "These results show that head cooling is very effective to reduce the physiological strain."
On topical skin cooling via spraying water, here are the two, and they both support that idea that it basically does no particular good in terms of lowering core temperature, although one study had mixed results as to the effectiveness.
• Journal of Appled Physiology, November, 1976, Davies CT, Brotherhood JR, Zeidifard E. Temperature regulation during severe exercise with some observations on effects of skin wetting.
• Med Sci Sports Exerc, February, 1987, Bassett DR Jr, Nagle FJ, Mookerjee S, Darr KC, Ng AV, Voss SG, Napp JP. Thermoregulatory responses to skin wetting during prolonged treadmill running.
On the subject of stomach temperature and cold fluids, here is an interesting pair of citations, on which I'll comment just below:
Sports Medicine, Sept/Oct, 1987, Murray R., John Stuart Research Laboratories, Quaker Oats Company, Barrington, The effects of consuming carbohydrate-electrolyte beverages on gastric emptying and fluid absorption during and following exercise. The author says, "Gastric emptying rate may be influenced by a variety of factors including, but not limited to, the caloric content, volume, osmolality, temperature, and pH of the ingested fluid, diurnal and interindividual variation, metabolic state (rest/exercise), and the ambient temperature.
Int J Sport Nutr Exerc Metab, December, 2000, Gastric emptying of cold beverages in humans: effect of transportable carbohydrates, Shi X, Bartoli W, Horn M, Murray R., Gatorade Sports Science Institute, Barrington, IL 60010, USA. The authors say, "Within 5 minutes after ingestion, cold beverages are warmed to above 30 C in the stomach. This infers that the effect of cold solution temperature on gastric emptying rate is likely to be small and transitory."
Those two articles above seem to contradict each other and they do. They're by the same author, Dr. Bob Murray, who is a friend of mine (and who runs the Gatorade Sports Institute). The former study is 13 years older, and supports earlier work by David Costill. The latter statement––made last year––is made in the light of further study (as explained to me by Dr. Murray). He is certainly one of the honchos in this field, and if he says fluid temperature is not a big issue in stomach emptying, one must pay attention to that.
Yet a honcho of similar (or perhaps greater) size in this field is Dr. Tim Noakes of South Africa, who writes, "Fluid consumption during exercise is enhanced by the ingestion of cold, sweet fluids." (Exerc Sport Sci Rev 1993, Fluid replacement during exercise. Noakes TD).
And here's from: 1996 American College of Sports Medicine position stand: Exercise and fluid replacement, (Med Sci Sports ExercJanuary, , Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC Jr, Sherman WM. "It is recommended that ingested fluids be cooler than ambient temperature [between 15 degrees and 22 degrees C (59 degrees and 72 degrees F.]"
Also interesting (but only tangentially germaine) is a variety of studies (of which Noakes is often the auther) on body mass and thermoregulation. The idea is to draw a line between light runners and fast running (perhaps suggesting that one important reason elite runners run so fast is that they don't generate so much heat). Noakes says, "It is concluded that, compared to heavier runners, those with a lower body mass have a distinct thermal advantage when running in conditions in which heat-dissipation mechanisms are at their limit. Lighter runners produce and store less heat at the same running speed; hence they can run faster or further before reaching a limiting rectal temperature."
I bring this up because one might assume that in a race like the Ironman––especially the Hawaiian Ironman––lighter is better. Yet while elite runners average perhaps 125 pounds, Greg Welch is the only male athlete under 145 pounds ever to win the race (and perhaps 150 pounds, I'm not quite sure of the weight of Thomas Hellriegel or Luc Van Lierde), and "optimal" (based on results) seems to suggest that 155 - 160 pounds is best. Most Ironman winners have fallen into that range. I bring this up simply to suggest that for whatever reason triathlon––and long, arduous triathlon in particular––seems to buck scientific intuitive thinking.
Science is good, but science is funny. Here's one for you:
• New Zealand Medical Journal, October, 1976, Dawson NJ, Thermoregulation during mild exercise. "A comparison was made of the thermoregulatory effects of wearing black or white clothing during exercise under radiant heating. For subjects in black clothing the skin temperature was higher than with white but the rectal temperature and heart rate were lower." (See Pflugers, Dec. 2000, in the bibliography below).
In other words, drinking cold water isn't any better than drinking warm water, but if you want to keep your core temperature down, wear black clothing when you race?
Here's my favorite, only because of the visual image I get:
• Br Poult Sci, September, 1996. Zhou W, Wang J, Yamamoto S. Faculty of Applied Biological Science, Hiroshima University, Japan. Effects of heat production attributable to forced walking on thermoregulatory physiological responses of chickens in a warm environment.
In the authors' own words: "To determine the effects of heat production on thermoregulatory physiological responses, five chickens were forced to walk to increase heat production."
There are new ways of determining stomach fluid temperatures during exercise. Several participants in this year's Ironman in Kona were given "pills" to swallow that actually recorded temperature during the event, to be (obviously) studied later. This ought to yield some interesting results. It is also possible to record gastric emptying rates via breath analysis. (I wonder whether there's another race gadget for us to use in our future?).
As I believe I said in the articles above, I'm certainly not saying that any of these tactics––cooling the head, wetting the skin, drinking cool water––necessarily work. I'm also saying that while such tactics may get you to the finish line faster, it may not be for physiological reasons. What I believe I did say in demonstrable terms is that I hope for a discussion to develop from the article on thermoregulation.
So, for the exercise physiologist who wrote me the email: As alternative to poking at what's written above, add to what's written above, perhaps on our forum. (If you do want to take a look at a selection of what I looked at, below represents a start).
Int J Sport Nutr Exerc Metab 2000 Dec;10(4):394-403 Books
Gastric emptying of cold beverages in humans: effect of transportable carbohydrates.
Shi X, Bartoli W, Horn M, Murray R.
Gatorade Sports Science Institute, Barrington, IL 60010, USA.
J Appl Physiol 1976 Nov;41(5 Pt. 1):772-6
Temperature regulation during severe exercise with some observations on effects of skin wetting.
Davies CT, Brotherhood JR, Zeidifard E.
Med Sci Sports Exerc 1987 Feb;19(1):28-32
Thermoregulatory responses to skin wetting during prolonged treadmill running.
Bassett DR Jr, Nagle FJ, Mookerjee S, Darr KC, Ng AV, Voss SG, Napp JP.
N Z Med J 1976 Oct 13;84(573):273-4
Thermoregulation during mild exercise.
Dawson NJ.
Can J Appl Physiol 1999 Apr;24(2):173-87
Limitations to fluid replacement during exercise.
Maughan RJ, Leiper JB.
Department of Biomedical Sciences, University Medical School, Foresterhill, Aberdeen AB25 2ZD Scotland.
Sports Med 1987 Sep-Oct;4(5):322-51
The effects of consuming carbohydrate-electrolyte beverages on gastric emptying and fluid absorption during and following exercise.
Murray R.
John Stuart Research Laboratories, Quaker Oats Company, Barrington.
Med Sci Sports Exerc 1996 Jan;28(1):i-vii
American College of Sports Medicine position stand. Exercise and fluid replacement.
Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC Jr, Sherman WM.
Eur J Appl Physiol 2000 Jan;81(1-2):33-9
Thermoregulatory effects of three different types of head cooling in humans during a mild hyperthermia.
Desruelle AV, Candas V.
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