Running on hot days requires much more from the body than simply keeping up the pace. The rise in body temperature, increased sweat production, and accelerated fluid loss make hydration one of the most important factors for safety and performance.

Understand the Hydration in the heat for runners it's not just a matter of comfort, but of prevention, performance and health. A well-planned strategy helps prevent loss of performance, cramps, early fatigue, and more serious conditions, such as thermal exhaustion.

Why does heat increase the risk of dehydration so much?

When we run in hot environments, the body uses sweat as its main cooling mechanism. Although this process is vital for thermoregulation, it is accompanied by significant losses of water and fundamental electrolytes, such as sodium, potassium, and magnesium.

Even mild dehydration, around 1 to 2% of body weight, is already capable of compromising physical endurance, motor coordination, and the body's ability to maintain a stable temperature. The result is often early tiredness, in addition to a greater risk of discomfort during and after exercise.

Before the race: hydration starts well before training

Many runners only think about drinking water in the minutes before training, but the state of hydration is built throughout the day. Maintaining a regular fluid intake helps the body start running in proper water balance.

A good reference is to ingest between 400 and 600 ml of fluids 30 to 60 minutes before exercise, adjusting according to the climate and the individual level of perspiration. In addition, it is worth reducing the consumption of alcoholic beverages and moderating excess caffeine, as both can favor fluid loss.

During the race: water alone is not always enough

For shorter runs, lasting up to 40 minutes, water tends to be sufficient, provided that prior hydration has been well done. On the other hand, during longer workouts, especially over one hour, simply replacing fluids does not maintain the body's ideal balance.

In these cases, the inclusion of electrolyte beverages helps to compensate for mineral losses and reduces the risk of a sharp drop in yield. As a practical guideline, many experts suggest an average intake between 150 and 250 ml every 20 minutes, always considering environmental conditions and individual response.

The role of electrolytes in performance

During sweating, not only water is lost. The outflow of minerals directly interferes with muscle contraction, blood pressure control, and neuromuscular efficiency.

Among the main electrolytes, the following stand out:

• Sodium, essential for maintaining blood volume;

• Potassium, important for muscle function;

• Magnesium, involved in relaxation and contraction processes.

When these nutrients are not replenished properly, the chances of cramps, marked fatigue, and feelings of weakness increase.

️ How to make running in the heat safer

In addition to hydration, small decisions make a difference in heat tolerance. Choosing milder times, such as early morning or late afternoon, significantly reduces heat stress.

Lightweight clothing, made of quick-drying fabrics and light colors help the body to dissipate heat. The use of sunscreen, cap or visor also protects against thermal overload caused by direct sun. Adjusting the pace on hot days is not a sign of weakness, but of sporting intelligence.

When to interrupt the race

Some signs indicate that the body is overstepping its limits:

• persistent dizziness;

• severe headache;

• nausea or a feeling of disorientation;

• excessively hot skin or chills.

Given these symptoms, the safest is Interrupt training immediately, seek body cooling and, if necessary, seek medical assistance. Insolation and thermal exhaustion are serious conditions and should not be neglected.

Conclusion

A Hydration in the heat for runners should not be improvised. It is as much a part of the training strategy as the volume and intensity of the race.

By properly planning fluid intake, adjusting electrolyte consumption and respecting the body's limits, runners preserve not only performance, but especially health. On hot days, hydrating well means running better.

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