Staying hydrated is vital when working out – here’s how

‘It’s important to begin exercise well hydrated,’ says nutritionist Anita Bean, author of The Complete Guide to Sports Nutrition (A&C Black, £16.99). ‘This means drinking 400-500ml fluid in the two hours before a workout. Your urine should be the colour of pale straw.’

‘People avoid drinking prior to a workout because they’re worried they’ll need a comfort break,’ says performance nutritionist Drew Price (www.drewprice.co.uk). There are several ways to avoid this. ‘First, drink earlier – it’s OK not to take on fluids in the hour before a workout if you’ve drunk adequate amounts in the previous hour. Second, don’t gulp, take sips. When you drink a lot of fluid in one go, it has a diuretic action. And third, if you’re really concerned you’ll be crossing your legs on the start line, swap water for a weak solution of a rehydration powder. This helps keep fluid in your body and loo trips at bay.’

During workouts, drink according to your thirst. ‘This will depend on several factors – if it’s hot, you’re working at a high intensity or you’re outdoors (so more water evaporates off you), you may want to sip,’ says Price. Otherwise, you’ll do fine without water until 45 minutes to an hour. ‘After that, aim to drink 300ml liquid per hour. Gradually, not all in one go.’

‘After exercise, drink 500ml fluid for every pound of weight you lost during training,’ he says. ‘It sounds complicated but all you need to do is weigh yourself immediately before and after. And if you’re confused about hydration, it’s a good way to understand exactly what you need.’
A final warning: hyponatremia is a condition in which blood levels of sodium drop dangerously low. It can occur when people undertaking endurance sports take on too much fluid, and the body’s cells flood with water. ‘Marathon runners have died because they went OTT on hydration,’ warns Price. ‘So use a sports bottle with measurements and watch you’re not overdoing it.’

By Hannah Ebelthite