How to hydrate for a 10km race

Avoiding dehydration is an important challenge for all runners. But running the 10km distance is a very different proposition to longer distances such as marathons. Here are some tips to make sure you hydrate properly in training and on Race Day at the Vitality London 10,000.

Avoiding 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, medical director of the London 10,000. "Take plenty of non-alcoholic drinks, especially when training in hot weather. Drink enough to keep your urine a pale straw colour."

You should drink plenty of liquids after training, especially long runs. If you think you'll need to drink during the race (there are Buxton Natural Mineral Water Drinks Stations at around 3km and 6.5km), make sure to you practise drinking on the run in training. Professor Sharma also suggests that you avoid alcohol in the two days before the race.

Avoiding hyponatraemia

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 because the 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 race," 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 race. 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 the 10km distance."

Drinking on Race Day

Start the race well hydrated. If you are 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 race, 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 of the London 10,000. Olympic and world 10,000m champion Mo Farah says: "Drink immediately before or after a 5km or 10km 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 five-time winner of the London 10,000, he certainly knows what he's talking about.

Strike a balance

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