Drink Wisely During Exercise
Too Much Fluid Can Be As Bad As Too Little
So How Much Should You Drink?
Not everyone goes quite so far. Other experts who spoke with WebMD agree
that it's terribly dangerous to drink too much water or too many sports drinks.
But they are uneasy about dehydration.
The USA Track & Field association web site carries advice from Noakes
and Douglas J. Casa, PhD. Casa is director of athletic training education at
the University of Connecticut.
"I'd bet many more people running Atlanta's Peachtree Road Race were
dehydrated than overhydrated," Casa tells WebMD. "I am not downplaying
hyponatremia. But the advice of don't drink the water is not good advice for
soccer and football players and runners who are out there sweating."
Casa stresses appropriate fluid replacement. So does Leslie Bonci, MPH, RD,
director of sports nutrition at the University of Pittsburgh Medical Center.
Bonci is the nutritional consultant for the Pittsburgh Steelers and Panthers as
well as for the Pittsburgh Ballet Theatre.
"It is not one size fits all," Bonci tells WebMD. "Each and
every person doesn't need same amount of fluids. Not everybody has the same
sweat rate, the same sodium loss rate."
Safe Use of Water and Sports Drinks
So how do you know how much to drink?
"The solution is not to drown oneself," Bonci says. "Just water
alone is not going to be the best recommendation. You also need something with
some carbohydrate and some electrolyte in it. So water alone during exercise,
no. Drinking until you slosh or drown, no. The guidelines are 20 ounces of
fluid before exercise, and over the course of every hour of exercise drink
between 28 to 40 ounces of fluid. That is not enormous quantities."
Casa has a simple rule. The next time you set out to exercise, weigh
yourself before going out. When you get back, step on the scales again. If you
lost weight, you should drink more the next time. If you gained weight, you
should drink less.
How much more or less? It's easy if you have a metric scale. For every
kilogram you lose (or gain) during exercise, you need a liter more (or less)
fluid. If you don't have a metric scale, it's one liter of fluid per 2.2
And don't forget salt, Bonci notes. It's also a good idea to know your
individual rate of salt loss. That can only be measured in a sports clinic. But
there's an easy way to tell if you lose a lot of salt when you work out.
"Some people are truly greater salt losers than others," Bonci says.
"Those whose sweat stings their eyes, those who get that crust on the skin,
should not put all their faith in sports drinks. Their salt should be from
food. Those who lose salt have to be more vigilant about adding maybe some
extra soy sauce to their meal the night before. And they have to be careful
about not overdoing it on fluids."