As soon as the thermometer rises, the same question always comes up: what should we really drink to get through the day? Between plain water, sugary drinks and electrolytes, it can be hard to know what to choose. We explain simply what works, what is pointless, and how to adapt your hydration when it is very hot.
Why hydration becomes critical during a heatwave
What happens in the body when it is very hot
When the temperature rises, the body sweats more to cool itself down. This sweating causes the loss of water as well as essential minerals such as sodium, potassium and magnesium. If these losses are not replaced, fatigue sets in quickly, concentration drops and headaches develop. That is why drinking plenty of plain water is not always enough during a heatwave.
Signs that show you are dehydrated
A dry mouth, dark urine, cramps or an unusual feeling of fatigue are often the first warning signs. In children and older people, these signs can appear more quickly and more severely. The simplest habit is to take small sips throughout the day, without waiting until you are thirsty.
These signs should be identified early. We have listed seven of them in our article about electrolyte deficiency.
Drinks to prioritize during a heatwave
Water, the essential foundation
Cool plain water, without being ice-cold, remains the go-to drink. The general recommendation is between 1.5 and 2 liters per day, more in cases of physical exertion or prolonged intense heat. Ideally, spread your intake throughout the day rather than drinking a large amount all at once, which simply causes the body to eliminate it without any real benefit.
Electrolyte drinks to replace lost minerals
When sweating increases, water alone does not replace the sodium, potassium and magnesium that are lost. This is where electrolyte-enriched drinks are especially useful, particularly during prolonged exercise or an especially hot day. Buddy electrolyte sticks help replenish these reserves without adding sugar, thanks to a combination of potassium, magnesium and sea salt that can be mixed directly into a bottle of water.
Homemade iced teas and infusions
Cooled light tea or a homemade fruit infusion, with no added sugar, also contributes to your daily fluid intake. They also add some variety when drinking water all day becomes monotonous.
If you prefer to prepare your drink yourself rather than buy it, we provide the proportions in our homemade electrolyte drink recipe.
Drinks to avoid in hot weather
Alcohol, sodas and very sugary drinks
Alcohol promotes dehydration and intensifies the effects of heat on the body, so it is best to limit it considerably or avoid it altogether on heatwave days. Sodas and very sugary drinks provide a passing feeling of freshness but can increase thirst shortly afterward.
Too much coffee
One or two cups during the day are not usually a problem, but too much coffee can increase the diuretic effect and therefore water loss. It is better to keep your usual coffees and make up the rest with water and hydrating drinks.
To choose a suitable formula, our electrolyte drink guide explains what to look for on a label, and drinkscore.info compares the actual contents of brands on the market.
Hydration and exercise during a heatwave
Adjusting your efforts and intake
Running, cycling or training in hot weather greatly increases water and mineral loss. The simplest approach is to move your sessions to early morning or evening, reduce the intensity and plan an electrolyte drink for efforts lasting more than 45 minutes to an hour. For a short session, water is more than enough. For longer exercise or intense heat, adding electrolytes helps limit cramps and maintain a good energy level until the end of the session.
Running in hot weather requires precise guidelines depending on the distance. We have brought them together in our guide on how much to drink while running. And for days when you sweat without exercising, our electrolyte powder dissolves in a water bottle and can be dosed according to the heat.
FAQ: your questions about hydration during a heatwave
How many liters of water should you drink during a heatwave?
In general, the recommendation is between 1.5 and 2.5 liters of fluids per day, increasing gradually in cases of physical activity or heavy sweating. This amount can vary depending on each person's age, weight and health.
Which drinks should you avoid in hot weather?
Alcohol, very sugary sodas and too much coffee should be limited because they increase dehydration instead of compensating for it.
Are electrolyte drinks really useful during a heatwave?
Yes, especially in cases of heavy sweating or prolonged physical exertion. They help replace lost sodium, potassium and magnesium, which water alone does not do.
Can you drink too much water during a heatwave?
Yes, drinking excessive amounts of water without any mineral intake can dilute the sodium in the blood. It is better to drink regularly in small amounts rather than large quantities all at once.
Which drink should you choose for a child or an older person during a heatwave?
Water remains the priority, along with careful monitoring for signs of dehydration. A light electrolyte drink may be offered in cases of heavy sweating, always with the advice of a healthcare professional for young children.
Remember one thing: during a heatwave, drinking regularly matters more than drinking a lot all at once. By combining water, suitable electrolyte drinks and a little common sense regarding physical exertion, summer becomes much easier to get through.
