New Hydration Study Presented At
American College of Sports Medicine Conference
Shows Many Athletes May Be Running On Empty
New research on athletes' perceptions of sweat loss and fluid consumption shows how critical it is for active people to drink on a schedule to prevent dehydration. The findings of the recent study will be presented this Friday, June 1, 2001, at the 48th Annual Meeting of the American College of Sports Medicine (ACSM) in Baltimore.
The study, conducted by scientists at the Gatorade Sports Science Institute (GSSI) in Barrington, Ill., looked at how accurately athletes could estimate their sweat losses and fluid consumption during a 10-mile race. Eighteen seasoned runners participated in the study. [strong]The results showed that the runners drastically underestimated how much sweat they lost and consequently drank too little to stay well hydrated. The runners underestimated their sweat losses by an average of 46 percent and their fluid intake by an average of 15 percent, resulting in the runners replacing only 30 percent of their fluids lost through sweat.[/strong]
"These data show that even the most experienced runners are unable to accurately estimate their sweat losses and cannot subjectively judge how much fluid to drink to prevent dehydration," said Mary Horn, M.S., co-author of the study and exercise sensory scientist at GSSI. "If seasoned athletes such as these do such a poor job of judging their fluid needs, the potential for dehydration may be more severe for the average exerciser, especially during the hot summer months."
Horn emphasizes the importance of drinking on a schedule every 15 minutes before, during and after activity and that the study demonstrates how relying on thirst is not enough to keep dehydration at bay.
According to W. Larry Kenney, Ph.D., vice president of ACSM, the research confirms what Kenney and other scientists have observed in laboratory experiments for years. "I've seen this 'voluntary dehydration' time and time again. From unfit periodic exercisers to elite athletes, it is difficult for people to judge the degree to which they become dehydrated. They don't replace the fluids they lose and often pay the price by compromising their athletic performance and even their health. Mary Horn's study provides nice documentation of this phenomenon during a simulated race."
The study was conducted during a competitive 10-mile race on a 400-meter track. Participants were given access to a sports beverage consisting of a 6% carbohydrate-electrolyte solution in a 20-oz. sports bottle at mile two, four, six and eight. They were allowed to drink at their discretion at each designated stop, as well as carry the bottle and drink while running. Despite this, the runners still became dehydrated.
"Research has shown that people will drink more of a lightly flavored sports beverage that contains sodium than they will water(1). Given the runner's still underestimated their fluid needs when given a lightly flavored sports drink, it's likely they would have replaced less fluid and had become more dehydrated if they drank water," added Horn.
Just as in a real race situation, if a participant bypassed a beverage station, the runner was not allowed additional fluid until the next scheduled stop. At the end of the race, each subject completed a questionnaire asking them to judge their fluid intake and sweat loss.
The Gatorade Sports Science Institute (GSSI), headquartered in Barrington, Ill., is a research and educational facility dedicated to enhancing the performance and well being of athletes. Research conducted by GSSI and in conjunction with leading universities throughout the world has resulted in hundreds of studies published in peer-reviewed scientific journals. For more information about sports nutrition and exercise science pertaining to The Gatorade Company, visit the Gatorade Sports Science Institute web site at www.gssiweb.com or gatorade.com.