We are often advised to drink 2 litres or 8 glasses of water per day. While this might be ok for some people at certain times, the real need for hydration varies a lot day to day. It is influenced by activity levels, by the surrounding temperature, the individual sweat rate, and so on.
My Advice: Drink to thirst
Listening to the feeling of thirst is enough to keep your hydration status in check. You begin to feel thirsty when the concentration of your blood has risen by around 2 %. Dehydration happens at around a 5 % increase, so thirst signals a good time to drink and it comes soon enough to avoid any problems.
There is one exception to this rule and that’s exercise. Unless you’re a trained athlete acclimated to the current temperatures doing a routine training session, you should drink on schedule. During long exercise sessions, especially in a hot climate, your body loses water faster than it can take it in. So, if you wait for thirst signals to appear, you will never catch up and dehydration will only get worse.
Next time we will take a closer look at what and how much to drink when exercising. You can test your understanding of hydration in our quiz.