I have to factor in extreme heat when managing type 1 diabetes during training and racing
For example, heat in the sauna usually lowers my glucose levels quite quickly but the same doesn’t always apply to training in heat and I wanted to find out why:
High- and low intensity exercise
Another factor significantly affecting my blood sugar – and it comes in most cases hand in hand with training in hot weather - is dehydration. Whilst this may not necessarily occur during short, high-intensity exercise in hot weather, I found it to result in elevated blood glucose levels both at high and moderate intensity training when exercise duration increases.
Dehydration is a vicious cycle because the more you sweat (and loose water), the more the body tries to take that fluid from somewhere else. It replaces it with water from the largest source of fluid, the bloodstream. As water then diffuses out of the blood, glucose is left behind. The overall blood volume is lower and the blood glucose concentration is higher.
For me being hydrated is key to keeping blood sugar levels stable. I have never calculated my sweat rate how much water in need to take on to replace the fluid I have lost but I have a few simple rules for example when out on the bike (when you easily forget drinking and don’t feel the heat so much due to the wind): On rides for more than 1.5- 2 hours at moderate intensity I usually have to take on a small amount of carbohydrate (CHO) every 20-25 minutes with a bar or similar every 45-55 minutes. Every time I have to eat, I then also drink some water/ electrolytes. I try not to wait until I feel thirst but equally don’t drink more when I feel “full”.