{"id":13091,"date":"2026-08-08T09:58:29","date_gmt":"2026-08-08T07:58:29","guid":{"rendered":"https:\/\/twindo-sportvoedingsadvies.nl\/?p=13091"},"modified":"2026-08-08T10:44:17","modified_gmt":"2026-08-08T08:44:17","slug":"exercising-in-hot-weather-nutrition","status":"publish","type":"post","link":"https:\/\/twindo-sportvoedingsadvies.nl\/en\/sporten-in-warm-weer-voeding\/","title":{"rendered":"Exercising in extreme heat: how hydration and nutrition affect your performance (and safety)"},"content":{"rendered":"
\n\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\n\t\n<\/svg>\t\t<\/div>\n\t\t
\n\t\t\t\t
\n\t\t\t\t\t

Exercising in extreme heat: how hydration and nutrition affect your performance (and safety)<\/h1>\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t

Published: 8 August 2026
Last updated: 8 August 2026
Reading time: 5-6 minutes
Categories Hydration<\/a><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

\n\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"An\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
\n\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t

We\u2019re having another hot summer. Lovely! But how do you train in these conditions? That\u2019s what this blog is about.<\/p>

After all, a tropical day brings with it a familiar dilemma for athletes: am I drinking too little, or too much? Both extremes can throw a spanner in the works: from a disappointing performance to, in the worst-case scenario, a medical problem. In this article, you\u2019ll learn how hydration and nutrition work together when exercising in (extreme) heat, and how to develop a simple, reliable strategy rather than relying on your sense of thirst.<\/p>

How heat affects your body<\/h3>

When exercising in hot conditions, your body has to do two things at once: supply your muscles with energy and keep your core temperature within safe limits. The latter requires blood volume. Some of your blood is directed to the skin to dissipate heat through sweating. The result is that, for the same level of exertion, your heart rate rises more quickly than on a cool day, and your sweat loss can increase significantly \u2013 from around one litre per hour to, in extreme cases, as much as three litres per hour \u2013 depending on the temperature, humidity and your own physiology.<\/p>

This is precisely why \u201cjust drinking more\u201d isn\u2019t the whole story. Fluid levels and the right electrolytes must remain in balance; otherwise, you\u2019re still at risk \u2013 in both directions.<\/p>

Before the training session: the right preparation<\/h3>

Don\u2019t start a training session in the heat whilst dehydrated. A widely accepted guideline is to drink around 500 ml of fluid about two hours before exercise, so that your body has time to excrete any excess fluid before you start. For longer or more strenuous exercise in the heat, it may also be a good idea to lightly replenish your fluids with electrolytes beforehand, especially if you know you produce salty sweat.<\/p>

During training: fluid and electrolyte balance<\/h3>

Thirst is a surprisingly unreliable guide. By the time you feel thirsty, you\u2019re often already somewhat dehydrated. It\u2019s better to drink on a regular schedule, tailored to your own rate of perspiration.<\/p>

What do the sports nutrition guidelines actually say? During exercise, it is recommended that you drink at a rate that is close to your rate of sweat loss, with a practical range of approximately 400 to 800 ml per hour during longer, intense exercise. In cases of very high sweat rates and extreme heat, this can rise to between 600 and 1,200 ml per hour. For exercise lasting longer than an hour, it is advisable to add both carbohydrates and sodium to your drink: this maintains your energy levels and helps you retain fluid more effectively.<\/p>

Important to know: Water alone is not always the best choice during prolonged, strenuous exercise.<\/strong> Pure water without sodium can, particularly during prolonged exercise and when consuming large volumes of fluid, increase the risk of hyponatraemia.<\/p>

Hyponatraemia: the opposite risk<\/h4>

Whilst most people fear dehydration, hyponatraemia is at least as real a risk during exercise in hot weather and is often overlooked. It occurs when you drink too much water without replenishing sufficient sodium, causing the sodium level in your blood to drop too low. Initial symptoms resemble those of dehydration (nausea, confusion, headache), which can be misleading, but the solution is exactly the opposite: drink less, consume more sodium. An isotonic sports drink containing electrolytes, rather than plain water, is your best safeguard in this situation.<\/p>

Warning signs: recognising heatstroke<\/h3>

As well as hyponatraemia, heatstroke is the risk you need to be aware of. It is important to understand the difference between this and mild heat exhaustion:<\/p>