From this week's Portland Fit news letter:

"In order to hydrate yourself properly on our long runs and walks, you need to be drinking 4-8 oz of water every 10-15 minutes."

Every week there is a seminar after the weekly run. I'm attending more of these this year already, since I have not had to rush home after the meeting. Last week's seminar was on hydration, where it was said that it is normal for a runner to lose 1-2lbs (up to about 1kg) of fluid each hour they run. The figure given above is the same information broken down into a more easily understood way.

I didn't understand, certainly.

The goal in hydration (that is, drinking while running) is to replace the fluids and electrolytes (sodium ions, mainly) lost through sweat. Given that each mouthful of fluid is approximately 1 fl oz (something demonstrated quite effectively in last week's seminar using a turkey baster), and that last year I drank a couple of mouthfuls every ten minutes, then I was drinking during runs at a rate of around 1-2 fl ozs every ten minutes ie about half the suggested replacement rate.

There are a couple of corollaries to this (everyone sweats at a different rate, for instance), but this piece of information that I was drinking fluids at about half the rate needed to replace what I was losing would help explain the repeated phenomenon of dying on my arse that I was experiencing towards the end of the long runs last year.

(incidentally, I don't wish to suggest that 4-8 fl oz every ten minutes is a reasonable rate to drink at when you're just sitting at your desk. I think that would be a little excessive)

Posted by Dunx at April 21, 2004 09:56 AM