Imagine you are in Mont-Tremblant racing a Half Ironman. You are running in the afternoon, the sun is at its hottest and the thermometer reads 33 degrees Celsius. It is hot out there! When I got to the half marathon portion of the race, there were sensations of chills and my fingers felt like they were slightly swollen. At the end, nausea and light headed sensations were present. If my body was not going through heat exhaustion, it was surely getting very close to it and so were other athletes that weekend, at varying degrees.
Can this be prevented? In a long-distance event, it may be harder than it seems, especially if the weather is showing its nasty side. Hydration and fuel will help your body function better in extreme environments. Your body works hard in many ways to lower or increase its temperature.
It was so sunny, that you had the sun directly on you for practically the entire event. Every chance that you got to go in the shade would help. No shade equals the sun heating your body.
The other way to get cooled down would have been through convection of air and water. There was not much wind when we were running so we had to depend on the different water station. Pouring water on your head is a good way to help cool down your body. The only issue here is that it might not be the easiest thing to do when you are racing. Having over 2000 participants going through a cycling path means that you’re bound to have people stop in the middle of the path to fuel and block others from being able to properly hydrate and fuel on the go. This might be part of the reason why my body was not going well towards the end. Sometimes your mind plays tricks on you when you are racing and you believe that you can skip one station because there were too many people blocking the way.
The final most important way that a body dissipates heat into the environment is through evaporation. Sweating alone will not cool you down. It is the evaporation of the sweat that will lower the body heat. The rate of evaporation changes with the % of relative humidity in the air. If you do not hydrate properly, you will not be able to sweat forever. In an hour of exercise, you can lose anywhere between one and two litres of water. Water is not unlimited in the body. If we get severely dehydrated, the body stops sweating and then the temperature increases and we are in danger of going through heat exhaustion or even heat stroke. Your judgment does not get better as you get tired. Again here, skipping a water station because there were too many people will only cause you more trouble in the long run (pun intended).
How do you prepare for extreme environments? Getting used to the heat might be a start. Even if you are acclimatized, hydration prior to the race is paramount. Too much caffeine or alcohol the days before is never a good idea. Consume foods that are high in water content such as fruits and vegetables. Unless you keep drinking, try to stay away from dried foods. Keep drinking and find something tasty to encourage you to hydrate in racing and training. Interestingly enough, carbonated drinks will tend to make you feel full and hydrate less (perhaps Perrier on a hot day was not the best idea).
We all make mistakes but what’s important is that we learn from them. Extreme conditions will make it more challenging to stay properly fuelled in an event. You will definitely eat differently on a cold rainy race compared to an extremely hot one. Feeling hungry in a race is never a good sign, especially when you do a triathlon, trust me on this one!
You can see below the chart of signs of heat exhaustion and heat stroke. Good luck on your training and your future races!
Physiology Of Sport and Exercise, Fourth Edition page 265