Into the Fire: Playing, Training, and Racing in the Heat
by Derek Salley
If anyone even so much as whispers that it’s too hot out this summer I’m going to have my biggest friend come over and whack that person, HARD. After the “winter from ayche eeee double hockey sticks”, it’s about time we got some nice sunny days and summer-like conditions! One of the best parts of living in Canada is enjoying the bugs, humidity and UV rays that can only be found in The Great White North in the months we so lovingly refer to as construction season. But even the most hard-core beach-lounging specialists must be vigilant with their backsides and front-sides, being oh-so-close to our favourite star over the summer months.
Note- this week’s installment will include a great deal of anecdote as well as supporting referenced material.
Whether we are playing, training, or racing in the heat, we face a whole new set of challenges that we didn’t need to worry about less than two months ago, back when there was still snow on the grass. When we are active outdoors in hot and sunny conditions, we face this challenge on a spectrum, ranging from minimizing reduced performance capacity, through struggling to maintain performance at any level, all the way to exposing ourselves to grave harm through exposure. It’s important to be aware of the means by which we mitigate exposure to heat and sun on every level, and be proactive so as not to find ourselves at the wrong end of that spectrum. Wearing sunscreen, hats and suitable clothing is a no brainer but what else is important to know about being out in the heat?
What happens to us as temps rise? According to Susan Paul, Runners World, “As blood flow is redirected to the skin’s surface, it means less blood is available to your working muscles. With less blood available, the heart is forced to work harder to sustain hard running, and the result is a higher heart rate” and as well “Since sweat is composed of plasma from your blood, sweating can decrease blood volume.” Our bodies make great efforts to cool the body core temperature through sweat which is intended to provide evaporative cooling. Furthermore hotter air is less dense (lower oxygen level by volume), and thus respiratory rate increases to provide relatively the same amount of oxygen to our body.
How does this impact fatigue? According to a study by González-Alonso, Teller, Andersen, Jensen, Hyldig and Nielsen from the Journal of Applied Physiology, “…high body temperature per se causes fatigue in trained subjects during prolonged exercise in uncompensable hot environment” and “time to exhaustion in hot environments in trained subjects is inversely related to the initial level of body temperature, and directly related to the rate of heat storage” More simply- being cooler to start and shedding heat better prolongs performance before fatigue to exhaustion. Increased heat can lead to dehydration and dehydration brings its own army of evil. From a study by Asker Jeukendrup, PhD, and Michael Gleeson, PhD. the following effects are observed when we become dehydrated: “Reduction in blood volume, decreased skin blood flow, decreased sweat rate, decreased heat dissipation, increased core temperature and increased rate of muscle glycogen use.
To recap our concern, without mitigation, performance decreases and fatigue increases as temperatures and commensurate body core temperature rises. As well, fluid loss rate increases and blood volume is reduced as efforts are expended in the high temperature environment; and dehydration can compound all of the above. None of that sounds particularly enticing and yet day after blazing sun day, we subject ourselves to enjoying hot weather and summer competition and racing as much as we possibly can?
How to beat the heat?
Many athletes simply avoid the hotter parts of the day, and yet while it’s easy to enjoy cooler mornings to train, and in some more southern locales this is essential- Texas, California and Louisiana from May to October come to mind; following the military “train-as-we-fight” concept, acclimatization is a better approach if you intend to compete in hot conditions. Jim Rutberg of Carmichael Training Systems describes acclimatization to high ambient temperatures as “… an active process of ‘heat training’, where your activities are designed to improve your performance in hot environments.” This idea is affirmed by Fortney and Vroman in a US National Library of Medicine NIH article: “…performance is often impaired by high ambient temperatures, but may be improved by programmes of physical training and heat acclimatization.”
In turn the heat-acclimatized body makes the following adaptations in an effort to be at its best in higher temps according to Rutberg. Individuals who have undergone heat acclimatization:
“-Start sweating sooner: To stay ahead of rising core temperature, your body kicks your primary cooling system (sweat) into action earlier than when not heat acclimated.
-Sweat more profusely: Your body learns to open the floodgates to get more fluid onto the skin surface for evaporative cooling.
-Sweat more evenly: You have sweat glands all over, and your body needs to increase evaporative cooling you’ll start sweating from everywhere.
-Change the composition of your sweat: The electrolyte content of your sweat decreases as your body tries to pump out more fluid but retain minerals needed for the nervous system and other critical body functions.
-Increase plasma volume: Your blood is what’s transporting heat from your core to your skin for radiant cooling as well as evaporative cooling. Increased plasma volume increases your capacity for heat transfer, and provides fluid for sweat.”
Working up to it is best and always with the provisos: train moderately, and fuel and hydrate adequately. Face the demon- plan to train in conditions you will experience normally in summer competitions. Exposing yourself to higher temps in training will lead to better race day or competition day results. A good cold weather strategy if you’re planning a winter trip to hot destination is wearing long-sleeved/ heavier clothing in a warmer room for indoor training sessions.
With acclimatization achieved, there are still plenty more strategies to employ in an attempt to keep cool. ProTour cyclists employ cooling vests, cooling wrist bands, fans, water soaked towels, ice, ice packs… in order to lower core temperature prior to and during races. How crucial are these efforts? From a performance thesis by Adam Tenforde, Stanford University: “Based on the results of the responder group, it appears that cooling is an effective means to increase performance in maximal exertion exercises, as the cooling trials for the responder group resulted in faster time trials, as well as higher average and maximum wattage compared to control conditions.” and “Results show that lowering core body temperature results in lower overall relative oxygen consumption during prolonged exercise.”
Recently one of my athletes competed in a triathlon in the Prairies in 30C temperatures. Strategies for keeping cool included training in the heat to acclimatize, insulated bottles filled with ice, staying out of the heat before race time, finding shade whenever possible, and in addition (when was the last time you saw a triathlete do something to be less “hardcore”?) he cracked a single use ice pack (available at pharmacies, etc) coming out of the swim and rode with the ice pack on his back under his suit. How effective was it? From his post race report “Critical Gear Success: One time use first aid ice pack in the back of the tri suit was KEY to my success in this race. I broke it at T1 and shoved it in my back. It kept me cool for the first 15-20km and had noticeable effects for 25-30km.” In his first triathlon ever, he won his age category and placed 18th out of more than 120 competitors. Regardless of the mechanism (actual gain or placebo?), he “felt” better and in feeling better he performed better in what can only be considered significantly adverse temperatures. Bottom line is that he beat his competition on the day.
A few years back, a couple of my friends and I participated in the inaugural Deer Creek Challenge in Colorado, touted as the toughest single day century ride in North America. The ride features 12,751′ of climbing over 172 kms, in temps topping out in the mid to high 90s Fahrenheit. One of my buddies seemed almost drunk as we arrived at one of the rest stations. He has a daze or a fuzziness about him. It was apparent that he was bonking from the effort, poor hydration and from the oppressively hot weather. The organizers of the ride rather brilliantly included Mr. Freeze popsicles in the selection of refreshments. We got my buddy out of the sun, cold water on the head and jersey, cool wet paper towel on his neck, he drank a full bottle with electrolytes and COLD water, AND we got him two big popsicles. Like water to a wilting plant, he bounced back and felt great only 15 minutes later, thereafter completing the ride with a strong finish.
One of the top stars years ago in motocross and certainly one of the fittest racers ever, was Mike Larocco. After an incident where a fellow racer won the first of the day’s two “motos” in the small engine class only to be hospitalized immediately thereafter with heat exhaustion, Mike was interviewed by one of the industry magazines and had the following recommendations: keep moving and avoid mistakes that lead to stopping moving (to facilitate evaporative cooling; don’t fall, don’t wipe out, don’t stop!), avoid going all out, instead carefully managing effort to maintain a tolerable sense of core temperature- hot days can be won by not making costly mistakes that sap the body of energy and cause body core temp to skyrocket: and be well hydrated prior to and stay well hydrated throughout such days – not just water but electrolytes.
How might I apply these ideas to a novice/developing runner who is trying a half marathon for the first time, by way of example? I’m a huge fan of the run+walk strategies popularized by John Stanton of Running Room fame, but on a smoking hot summer day, I’d recommend modifications – walk only in shaded portions of the course if available, rather than on a set period or time-based targets; slow but don’t walk through aid stations; more electrolyte consumption rather than straight water (all else being equal); at least a pair of cups of water over the head and body through each aid station, reduce target HR and pace to recognize the need to conserve in the heat, sponges and popsicles if offered through aid stations, and so on. Even before the race, training to acclimatize, super strong adherence to pre-race hydration and nutrition to include topping glycogen stores in the days leading to race day.
The same principles apply regardless of your chosen athletic vice/endeavour. If you’re on a group ride for example, and the group pulls in to the Quickie-Mart for a bottle stop, don’t wait outside – stay in the air-conditioned comfort of the store as long as you can. Eat that popsicle, start with a nearly frozen bottle in your back cage and lots of ice in the front bottle, find shade when possible, stay ahead on hydration and electrolytes, keep glycogen stores topped, avoid going 10/10s and carefully manage your effort. Plan on one bottle per hour or more in the heat and according to an article by Casa PhD from the Journal of Athletic Performance, fluid uptake to the body is improved when beverage temperature is between 10 and 15C. Don’t stop if you can avoid it and if you do, minimize your time at a standstill. Watch your friends too. Like any bonk, the earlysigns will include reduced awareness, reduced stability, performance “fragility” – not being able to match an effort or pace on even a small grade; all the way to complete loss of ability to maintain pace or effort.
For anyone competing at any level in the heat, the rewards of showing up with a plan and well-executed training are immense. On a day when others suffer, you will win. You will feel better at the finish line, you will compete stronger and remain stronger longer, you will take mental gains from the suffering of your competition, adding to your own confidence and your belief and affirmation in your own training and process. Get out there and enjoy our construction season of playing, training and racing!