Fluid intake

Along with energy depletion, dehydration – or loss of fluid – is one of the main causes of tiredness, especially when exercising in hot or humid conditions. Fluid isn’t only lost from sweating – we also lose it from the air that we exhale from the lungs, so even on the coldest of days, people exercising need to maintain their fluid levels.

Over the past few years, a considerable amount of research has been devoted to finding the optimal type of drink for people who are exercising. It’s been concluded that there are essentially two main types of drink that are of most benefit for those involved in exercise.

Water

Water – the most natural of all fluids – is great for keeping you hydrated. Remember, water doesn’t replace the energy you’ve expended. Water takes longer than a sports drink to be absorbed by the body.

Energy drinks

Energy drinks are high in carbohydrate – usually to a concentration of around 20%. Their high concentration of energy actually slows down the rate at which fluid is absorbed, so they’re best used as ‘meal replacements’, either sometime before or after exercise, as an alternative to eating.

In this section

They’re handy for sportsmen and women competing away from home or travelling, and are also useful for people who don’t feel like eating a meal after they’ve finished exercising.

Sports drinks

These have less carbohydrate than energy drinks – normally a concentration of around 5–8% – as well as a small amount of sodium (salt). Although they contain less energy, they’re absorbed far more rapidly by the body than energy drinks. This is because their concentration is similar to that of the body’s own fluids – so this type of drink is often called ‘isotonic’. Isotonic drinks are an excellent way of replacing fluid quickly, as well as providing a rapid source of energy. They’re ideal for exercise in hot and humid conditions, and can be drunk before, during and after exercise.

Drinks to avoid

Drinks to avoid include high protein drinks because – just like protein foods – they won’t increase muscle size and strength. Caffeine – contained in tea, coffee and the recently arrived ‘pick-me-up’ stimulant drinks – is a diuretic, which means they can cause urine to be produced in large quantities. Not only does this actually increase the risk of dehydration, it’s also not ideal if you’re trying to exercise. Large amounts of alcohol are also not to be recommended for people taking part in sport and exercise. Like caffeine, alcohol also causes dehydration, and contains large amounts of calories, which can cause in weight gain