News Release Distributed 07/15/10

Proper hydration is essential for healthy physical activity. Drinking the right amount of fluids before, during and after every physical activity is vital to providing the fluids the body needs to perform properly, according to LSU AgCenter nutritionist Beth Reames.

“The risks of dehydration and heat injury increase dramatically in hot, humid weather,” Reames says. “During preseason athletic practices with high heat and humidity, it is necessary to take every precaution to assure that athletes are well hydrated, have access to fluids and are monitored for heat-related illness.”

Evaporation of sweat during physical activity helps to cool the body, she says. Dehydration results when individuals fail to adequately replace fluid lost through sweating. Dehydration can lead to higher body core temperature, which increases strain on the cardiovascular system and may lead to heat stroke, heat injury and even death.

Dehydration also impairs performance by causing cramps, weakness and headache. Dehydration that exceeds two percent body weight loss harms exercise performance, and dehydration of greater than three percent of body weight increases a person’s risk of heat illness, such as heat cramps, heat exhaustion and heat stroke, the AgCenter nutritionist says.

According to a 2005 article in the Journal of the American College of Sports Medicine, fluid replacement should be promoted by providing chilled fluids, easy access, and adequate time for ingestion, to encourage sufficient fluid intake and lessen progressive dehydration on the field.

Reames recommends water for most types of exercise of one hour or less under moderate temperature conditions. She recommends sports drinks or diluted juices containing carbohydrates in concentrations of four percent to eight percent for athletes engaged in moderate to high-intensity exercise that lasts an hour or longer.

“Sports drinks are flavored beverages and are often preferred over plain water,” Reames says. “They also replace electrolytes such as sodium, which is lost in sweat. However, foods eaten after an event are usually sufficient to replace sodium.”

Reames offers these tips to promote proper hydration:

– Drink before, during and after practices and games.

– Drink early. By the time you’re thirsty, you’re already dehydrated.

– Include liquids with the pre-competition meal.

– Drink fluids based on the amount of sweat and urine loss during the activity.

– Drink cool fluids.

– Replace fluids lost in sweat and urine after the competition.

Reames says basic guidelines for fluid replacement include drinking two cups of fluid about two hours before exercise or competition and drinking early and regularly during exercise to replace water lost by sweating – one-half to one cup of fluid every 15 to 20 minutes. After exercising, drink at least two cups of fluid per pound of body weight lost during exercise.

“The overall goal for proper hydration is to minimize dehydration without over-drinking,” she says. Practical ways to monitor hydration include urine color, daily body weight and sweat loss.