Dehydration advise from Dr. Mirkin - Triathlon Week

sfricks · 07-06-2006, 07:43 AM

This article picked up from drmirkin.com

Dear Dr. Mirkin: Can dehydration be prevented by drinking sports
drinks instead of water?

No. Sports drinks contain a small amount of salt, but not
enough to meet your needs. A study in the British Journal of
Sports Medicine showed that you cannot replace salt lost through
exercise exclusively by taking salty fluids (April 2006). If you are
exercising for a long time in warm weather, you need to replace
fluid, salt and calories. Salty drinks taste awful, so none of the
popular sports drinks contain much salt. You need to eat salty
foods along with the beverage of your choice. Since thirst is a
very late sign of dehydration and lack of fluids during endurance
exercise can kill, all exercisers are encouraged never to wait for
thirst to tell them when to drink. By the time an athlete becomes
thirsty during a competition, it is too late to drink enough to
replenish the fluid loss without stopping to rest.
Many people fear hyponatremia (collapse or even death
from too much water during exercise), but sports drinks offer no
advantage over any other beverage. Hyponatremia is caused by
excess fluid from any source, not by lack of salt or calories.
During intense competition, athletes concentrate so hard on
maintaining their pace that they are unlikely to take in too much
fluid. However, novice athletes often run so slowly that they
spend more time drinking than pushing the pace. How much
fluid should you drink? The American College of Sports
Medicine recommends about a quart an hour during vigorous
exercise. For a person who is not exercising near his maximum,
this could be too much. The person who is exhausted and
exercising significantly below his capacity probably should take in
only about a pint per hour.