Knowing what to drink – and when – before, during and after an event isn’t always easy, especially as running 10K is different to longer distances such as marathons. Here are some tips to help you hydrate properly in training, on Event Day itself and beyond. 

Avoid dehydration...

When you sweat during a run, the fluid you lose must be replaced or your body becomes dehydrated (short of water) and less efficient.

“Alcoholic drinks, tea and coffee are dehydrating,” says Professor Sanjay Sharma, Vitality London 10,000 Medical Director. “Take plenty of non-alcoholic drinks, especially when training in hot weather. Drink enough to keep your urine a pale straw colour.”

If you think you’ll need to drink during the event, practise drinking on the run in training. Professor Sharma also suggests avoiding alcohol in the two days before the event due to its dehydrating properties.

but avoid drinking too much

A common mistake is consuming too much water in the days and hours before the race starts. Paradoxically, this can make you thirsty at the Start Line as your body releases a diuretic hormone to bring your fluid levels back to normal, and your increased bathroom visits can also contribute to dehydration.

“The best thing to do is sip regularly before the event,” says sports nutritionist Alexandra Rees. “Bear in mind that if you feel thirsty, you’re already dehydrated.” If you get a ‘sloshing’ feeling in your stomach, you’ve drunk too much.

Drinking too much can be very dangerous and lead to hyponatraemia (water intoxication), fits and even death. Professor Sharma says: “Drink when you feel the need and do not gulp large volumes of fluids before, during or after the event.

“Your needs vary with your build, speed and the weather. Faster runners may need as much as a litre of fluid per hour on a warm day but slower runners need less, particularly on a cool day, and should not drink more than 500ml per hour.

“After the finish do not drink large amounts of water. You can only rehydrate gradually over the next 24 to 48 hours. Eat some salty food as well as spacing your drinks. This way you will avoid hyponatraemia and still replace the water, salt and glycogen lost in running 10K.”

What to drink on Event Day

Start well hydrated. If you’re not already bursting, drink half a pint (around 250ml) of water or sports drink in the half hour before the start, says Professor Sharma. Sports nutritionist Emma Barraclough suggests that you drink 500ml from the time you wake up until the start of the event, and that drinks including sodium, such as Lucozade Sport, are better retained by the body.

You may not even need to use the Drinks Stations on the course. Olympic and world 10,000m champion Sir Mo Farah says: “Drink immediately before or after a 5K or 10K run, but not during it. Running with a bottle puts more pressure on whatever side of your body it weighs down, and running well is all about balance.” A seven-time winner of the London 10,000, he certainly knows what he’s talking about.

Striking the right balance

Getting the balance right between avoiding dehydration and not risking hyponatraemia is crucial. Learn in your training how much water you need and avoid making any drastic changes to your hydration on Event Day. If you do that, your experience at the Vitality London 10,000 will be one to remember.