Water, Exercise and Hydration
- Water is a life-giving nutrient making up about 60% of total body
weight for young adults and about 50% for the elderly.
- Various body components account for different percentages of the
body's water content; generally, water constitutes 65% to 75% of muscle
weight and 50% body-fat weight.
- The proportion of body water is generally smaller in females, the
elderly, in obese people because of smaller portion of muscle mass in these
populations.
- During exercise, you may lose about a quart of water (4 cups) per hour
of exercise. If it is hot and humid this loss will increase.
- Thirst is not a good indicator of dehydration, especially during
exercise.
Proper Hydration for Exercise
- Before Exercise: Drink 8 to 16 ounces (1 to 2 cups) of fluid (i.e.
water or sports drinks, but not carbonated beverages) two hours
before exercise. Then, drink 4 to 8 ounces (1/2 to 1 cup) of fluid
immediately before exercise. In very hot or cold weather, you will
need more water: 12 to 20 ounces (1.5 to 2.5 cups).
- During Exercise: Drink 4 to 8 ounces (1/2 to 1 cup) of fluid (i.e. water or sports
drinks, but not carbonated beverages) every fifteen to twenty minutes.
Carry a water bottle with you or make regular water breaks part of your
exercise routine.
- After Exercise: This is the time to replace any fluid you have lost.
Drink 16 ounces of fluid (2 cups) (i.e. water or sports drinks, but not carbonated
beverages) for every pound of lost body weight.
Sources of Information
- Juan, Wen Yen, Basiotis, P. More Than One in Three Older Americans May Not Drink Enough Water. Nutrition Insight 27. September 2002. Nutrition Insight. Accessed December 10, 2002
.
- American College of Sports Medicine. Exercise and Fluid Replacement. Position Stand. 1996. Medicine and Science in Sports and Exercise. Vol 28/No1
.
- Gatorade Sports Science Institute. Hydration. Accessed January 12, 2003 at http://www.gssiweb.com/sportssciencecenter/topic.cfm?id=57
.