Weather and dehydration

Environmental factors also play their part in the dehydration story – if you exercise in heat you’re going to dehydrate faster and feel the impact on your performance sooner than you would in cooler climates or temperatures.

In Hot Weather

Sweat rates can reach 2.5 litres per hour in hot and humid weather.1 That’s a lot of sweat, and if you don’t replace the fluids and minerals you lose, such a high rate of sweat loss can quickly lead to dehydration.

Dehydration and exercising in the heat dramatically affect your heart rate, body temperature regulation, concentration and performance.

If you’re training or competing in hot weather, it’s essential to gain heat experience.  This will help you learn how to adapt your training and competition strategies, as well as how much you need to drink, rather than suddenly exposing yourself to hot weather.

In Cold Weather 

In cold weather, you tend to forget about your fluid needs, perhaps thinking that your sweat needs are minimal.

But if you’re exercising in cooler conditions (less than 10°C), your risk of dehydration is often just as high as it is in hot conditions.

Be aware of your sweat loss when exercising in the cold, and drink according to your sweat rates.

  • 1Rehrer NJ, Burke LM: Sweat losses during various sports. Aust J Nutr Diet 53:S13–S16, 1996.

This information is not medical advice and should not replace consultation with your health care provider or nutritionist before starting a new exercise program or eating plan.