Training in the heat: what changes in your body and how to adjust your nutrition

Training in the heat increases the loss of fluids and electrolytes, can increase energy expenditure, and forces the triathlete to review their hydration, salt, and recovery strategy.

Summer changes the way you train. Not only because the temperature rises or because the sessions become more uncomfortable, but because the body works differently when it has to perform in warmer conditions. heat and humidity.

For a triathlete, this has a clear meaning: nutrition that works in spring may fall short in July or August. A long bike ride, a bike-to-run transition, or an interval session in high temperatures demands greater attention to hydration, carbohydrates, and electrolyte replacement.

Why heat changes training

When we exercise in the heat, the body needs to dissipate more heat. To do this, sweating increases and cardiovascular effort rises, as some blood flow is directed to the skin to help regulate body temperature.

This can make a session that would normally be controlled feel harder. The pace slows, the heart rate rises sooner, and fatigue sets in more easily.

From Crown Sport NutritionRegular contributors to the endurance ecosystem remind us that exercising in the heat doesn't just affect immediate performance. It can also impact recovery, electrolyte balance, and the ability to sustain prolonged effort.

More sweat, more salts, and a greater risk of dehydration

The first obvious change is the increased fluid lossIn high temperatures, the body sweats more to try to stay stable, and with that sweat, not only is water lost.

Electrolytes are also lost, especially sodiumPotassium is key to maintaining fluid balance during exercise. Potassium and magnesium also play a role in muscle and neuromuscular function, although the replenishment strategy should always be tailored to the duration, intensity, and sweat rate of each athlete.

In triathlon, this point is especially important during long cycling sessions or in competitions where the running leg comes after several hours of exertion. Often, the problem doesn't appear at the beginning, but rather when the body has already accumulated heat, fluid loss, electrolyte loss, and fatigue.

The body depends more on carbohydrates

Heat can also alter energy management. Under demanding conditions, the body tends to rely more on energy sources. carbohydrates, a key source for sustaining medium and high intensities.

This doesn't mean you should eat more indiscriminately, but rather that it's advisable to monitor your intake during training. If the session is long, intense, or takes place during the hottest part of the day, waiting too long to consume carbohydrates can have negative consequences.

For the average triathlete, a good practical guideline is to experiment with different combinations of drinks, gels, bars, or easily digestible foods during training. The key is to arrive at race day with a known strategy, not to improvise when the heat is already affecting performance.

Recovery is also complicated

Training doesn't end when the clock stops. In the heat, recovery can be compromised if fluids, salts, carbohydrates, and proteins aren't replenished in the following hours.

After a demanding workout, the body needs to replenish glycogen stores, repair muscle tissue, and restore fluid balance. If this is neglected for several days, fatigue can build up even if the training plan seems well-designed.

In summer, poor recovery isn't always immediately noticeable. Sometimes it manifests as poorer sleep, heavier legs, a feeling of a rapid heartbeat, or difficulty completing workouts that previously went smoothly.

How to adjust hydration, salts, and carbohydrates

The strategy should be adapted to the duration, intensity, temperature, humidity, and individual tolerance. Not all athletes sweat the same amount or lose the same amount of sodium, so it's advisable to experiment and adjust accordingly.

For short, easy sessions, water and a good daily diet may suffice. For longer workouts, very hot days, or high-intensity training, a combination of exercise and exercise is usually more beneficial. fluid, electrolytes and carbohydrates.

A simple guideline is to start hydrated, drink regularly during exercise, and not wait until you're very thirsty. During long workouts, sodium replacement can help maintain fluid balance, especially for athletes who sweat a lot.

What does Crown suggest for summer training?

Crown's proposal for heating is based on meeting specific needs: hydration with electrolytes, carbohydrate intake during exercise and subsequent recovery.

This approach includes products such as Isodrink & Energy to combine hydration, salts and energy; PRO Salt Caps to reinforce electrolyte replenishment; energy gels and bars to sustain the effort; and recovery formulas with proteins and carbohydrates for after training.

The important thing is not to always use everything, but to know what each session requires. An easy ride doesn't demand the same as a long bike ride, a running training at midday or a middle-distance competition.

Listening to your body remains key

Training in the heat requires planning, but also common sense. Reducing intensity, choosing better times of day, seeking shade, adjusting pace, and monitoring your body's sensations can be just as important as getting your nutrition right.

If you experience dizziness, chills, confusion, severe headache, or an unusual feeling of weakness, it's wise to stop and prioritize safety. Performance should never come before health.

The heat doesn't prevent you from training well, but it does require you to train more strategically. For triathletes, adjusting hydration, electrolytes, carbohydrates, and recovery can make the difference between accumulating good training sessions and arriving at summer dragging along fatigue.

This content has been created with the support of AI tools and reviewed by the Triathlon News editorial team.