How to stay hydrated when working out

Feeling thirsty, light-headed, tired, headachey, a dry mouth and lips are early signs of dehydration, so read our guide to what’s best to drink.

1. Water Water is the perfect hydrator. You should aim to drink at least 1.2 litres of fluid (six to eight glasses) a day and increase this to 2.5 litres in hot weather. Water is calorie- and fat-free and easily absorbed by the body. However, if you’re working out for longer than 60 minutes, switch to a sports drink (see below).

2. Squash or diluted fruit juice

If you find water boring, try highly diluted squash or fruit juice, for example, 100ml of fruit juice to one litre of water. Sugars can slow down the rate of absorption by the bloodstream. Smoothies also contain too much sugar and don't allow you to hydrate efficiently.

3. Sports drinks

A 2008 study found sports drinks don’t necessarily hydrate your body as fast as water, but they do provide a quick energy source. Isotonic drinks help replace lost minerals and provide some carbohydrate as fuel. Only have energy drinks with a higher level of carbohydrate after doing high levels of exercise, it will quickly replace muscle glycogen stores.

4. Tea

A recent UK study found drinking up to four cups of black tea is just as hydrating as drinking the same quantity of water. However, the caffeine in tea begins acting as a diuretic (increases fluid loss by causing you to pass more urine) when you exceed around five cups a day, so go easy or switch to herbal teas.

5. Coconut water

Fresh coconut water is naturally isotonic, with a 330ml serving containing more potassium than two bananas plus five other naturally occurring electrolytes. It has one-fifth of the sugar found in fruit juice, plus a little fibre.

6. Soft drinks

These along with various energy drinks, provide empty calories. They’re also acidic, and can damage your teeth when drunk regularly. Even vitamin-fortified drinks branded as ‘healthy’ can contain as much sugar as a cola.