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24 Feb 2004

fluid loss
Any idea how much fluid you lose on a 21km run? How much are you supposed drink?
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Expert
FitnessDoc
fitnessdoc

01 Jan 0001

Hi there

YOu generally lose between 500 and 1000 ml per hour, although there are so many factors affecting this. The temperature, the intensity, the humidity, even the type of sport, and the clothing. HOwever, this is a general range which is probably accurate.

Now, in terms of drinking, The best is really to drink to thirst - if you do this, then your body will pretty much let you know when you need to drink. THere are plenty of people who suggest that you should drink before you are thirsty, but all our research says that this is not needed. You will find that if you drink to thirst, you will probably drink between 400 and 800 ml per hour, depending on the day. Any more than this creates problems, because you just overload the system and it's actually quite hard to drink more than a litre per hour, especially during running. So, provided you drink a little at each station in a race you will be fine, and then you can always drink more when you are finished.

Regards
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