How heat affects the fuel for endurance performance

Carbohydrates and ambient temperature: How heat affects the fuel for endurance performance

For endurance athletes, carbohydrates are the most important fuel for maintaining performance. However, it's not just training intensity and duration that determine carbohydrate requirements. Ambient temperature also plays a crucial role – especially in hot weather. How exactly does temperature affect carbohydrate needs, and what does this mean for your diet and competition preparation?

Heat increases energy consumption

High temperatures significantly increase the strain on the body. It must not only supply the muscles with energy but also simultaneously regulate its temperature to prevent overheating. Cooling occurs primarily through increased sweating and improved blood flow to the skin. Both processes require additional energy. This increases overall energy consumption during endurance exercise, and more carbohydrates are needed to meet this increased demand.

This also has something to do with heart rate. The body tries to acquire the additional energy by increasing the heart rate and to dissipate heat from the body. This consumes additional glycogen and carbohydrates.

Carbohydrates as preferred fuel

While fats are slower energy sources, carbohydrates provide readily available energy – a crucial advantage in high temperatures when the body needs to function particularly efficiently. Studies show that in hot weather, the proportion of energy derived from carbohydrates increases compared to cooler conditions. Therefore, it is essential to adjust carbohydrate intake strategically during training and competition.

Practical nutrition tips for hot days

1. Increase your carbohydrate stores before hot training sessions or competitions by eating a carbohydrate-rich diet (e.g., 8–10 g of carbohydrates per kg of body weight in the days before).
2. During training or competition, 40–80 g of carbohydrates per hour is ideal, possibly even slightly more in very high temperatures.
3. Use carbohydrate-rich sports drinks that simultaneously ensure adequate hydration and compensate for the increased fluid loss through sweating.
4. Listen to your body: fatigue and decreased performance can be signs of insufficient carbohydrate intake, especially in hot weather.

Conclusion

Heat is an additional strain that significantly increases carbohydrate requirements during endurance activities. Adjusting your diet and fluid intake to the ambient temperature can prevent performance losses and improve endurance. Therefore, every endurance athlete should pay attention to the temperature, fuel properly – and maintain maximum speed.

Additionally, athletes should train to consume more carbohydrates, especially in warmer temperatures. This is often a problem, as athletes are already operating at their absorption limits. Sometimes, in hot temperatures and high humidity, it makes sense to actually reduce activity levels and allow for thermoregulation.

Sportbrennstoff wishes you every success in training and competition – at any temperature!