JUST HOW MUCH SHOULD YOU BE DRINKING FOR OPTIMUM RUNNING PERFORMANCE – AND WHEN? SARAH RUSSELL HAS THE LOWDOWN

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Drinking enough fluid to maintain proper hydration is essential for both your health and your running performance. But according to research, it’s estimated that around 70 to 80 per cent of the UK population doesn’t drink enough liquid on a daily basis.

WHY IS DEHYDRATION A PROBLEM?

Common symptoms, such as fatigue, thirst, headaches, irritability and poor concentration, can often be attributed to mild dehydration. A study of GPs found 10 per cent of patients seen in clinic for fatigue were simply dehydrated. The act of drinking enough seems such a simple health fix, but it’s clear many of us aren’t getting it right.

RUNNING PERFORMANCE

When it comes to running, even mild dehydration (1-2 per cent bodyweight) can cause cramping, fatigue, injuries (such as muscle tears) and reduced performance. One recent study from Loughborough University found during prolonged exercise, a two per cent drop in body mass through water loss resulted in a 20 per cent decrease in performance.

In marathon terms, that means adding around 48 minutes to a four-hour marathon. However, it’s normal to finish a marathon somewhat dehydrated. It would be impossible to replace 100 per cent of your fluid losses during the race. Instead, just think about trying to minimise fluid losses and make sure you start the race well hydrated. The practice of over-drinking during a marathon is becoming more common and can lead to hyponatremia, which can be fatal. But more about that later.