Sports and hot weather

Causes and symptoms

Exposure to heat and the practice of physical activity lead to significant sweating (which varies from one individual to another) and, consequently, increased water loss. If this is not compensated for, the body tends to become dehydrated.

When the ambient temperature rises, the body’s temperature naturally tends to rise, so the body tries to evacuate this heat. This outward evacuation involves very simple mechanisms such as sweating.

Sweat is 99% water, but the remaining 1% is undoubtedly the most important for the athlete’s body. This results in the loss of numerous minerals, the most important of which are Sodium, Potassium, Calcium and Magnesium.

The main warning sign that dehydration is beginning is the sensation of thirst. However, by the time the sensation of thirst arrives, the stage of dehydration is already well advanced, as is the risk of muscle cramps and pain.

The impact on performance

Numerous studies have shown that a state of dehydration can lead to a drop in performance. Figures show that a loss of 2% of body weight due to sweat loss results in a reduction in performance of over 20%!

If athletes fail to anticipate dehydration and hydrate regularly, their performance will suffer immediately. Lowered fatigue threshold, reduced concentration, attention, precision and even motivation are all factors linked to a state of dehydration and contribute to a drop in performance.

Health consequences

When dehydration is limited to inconveniences such as thirst and dry mouth, you’d think it would be easy to restore balance, but it’s not that simple! Even with frequent and abundant intake to alleviate thirst, we can’t fully cover the body’s water requirements. Sometimes, these discomforts turn into health risks for the athlete, and become more serious.

Hyponatremia, hypovolemia, edema, cramps, heat stroke and digestive disorders are often the direct consequences of this phenomenon.

One of the best things to do before exercising in hot weather is to acclimatize your body to this environment. Acclimatization can be achieved quite easily by gradually performing exercises in a warm environment.

To avoid dehydration, it’s essential to anticipate water intake before the start of exercise. Exercise preparation drinks, designed to fulfil this function by providing a source of energy, can be a good idea.

Secondly, and we can’t stress this enough, you need to drink regularly, even when you’re not thirsty. Whenever possible, try to drink every 10 minutes or so. For trail runners, the hydration bag plays a major role in thermoregulation and hydration. From 2L to 30L, many brands offer a wide range of trail backpacks.

During exercise, energy gels are available to compensate for this loss. Specially designed to boost endurance and performance during sports in hot climates, these gels can prove invaluable.

Beware, too, of beverages with excessive carbohydrate concentrations, as they favour carbohydrate intake at the expense of proper hydration. Drinks containing excessive caffeine, supposedly for its stimulating effect (energy drinks, for example), should also be avoided, as they further accentuate dehydration.

It’s a good idea to drink beverages with the right carbohydrate content (30 to 60g for an hour’s effort), enriched with minerals, particularly sodium and potassium, to make up for the losses that cause the above-mentioned phenomena.

Dehydration is therefore a phenomenon that influences a number of parameters, including performance and health. So it’s important to adopt the right reflexes to avoid dehydration and its consequences.