By Maureen Williams, ND

Healthnotes Newswire (September 13, 2007)—Staying well-hydrated during a basketball game might improve your chances of winning, a new study suggests.

The body loses water continuously: through the skin, through moisture in the breath, and through the water used by the kidneys to remove toxins when producing urine. Exercise speeds up water loss as the breath rate increases to keep up with oxygen demand and the skin sweats to help release excess heat. Without proper fluid replacement, a person exercising can quickly become dehydrated.

Severe dehydration is characterized by extreme thirst, confusion, lack of sweating and urination, rapid heartbeat, and eventually delirium and unconsciousness. Signs of milder degrees of dehydration, which are likely to occur with exercise, include thirst, dizziness, headache, fatigue, and weakness. Though often less than dramatic, mild to moderate dehydration has been shown to affect physical performance. Cyclists and long-distance runners, for example, move more and more slowly if they don’t replace the fluid lost during their workout.

The new study, published in Medicine and Science in Sports and Exercise, looked at the effect of increasing dehydration on athletic performance in adult basketball players. The 17 men who participated in the study did three hours of treadmill walking followed by a rest period, then 80 minutes of basketball drills. Each athlete performed this sequence on six different days, each time with a different hydration status: full hydration using a carbohydrate-enriched water and electrolyte drink, full hydration using water plus electrolytes, and partial fluid replacement to produce 1% dehydration, 2% dehydration, 3% dehydration, and 4% dehydration.

Basketball performance began to deteriorate at 2% dehydration. Timed drills were slower and fewer shots were made during the dehydration trials than during the fully hydrated trials. Compared with full hydration, heart rate and core body temperature during exercise increased and sweating decreased with rising degrees of dehydration. In the 4% dehydration trials, body temperature remained high even at the end of the rest period. The athletes also reported more feelings of light-headedness, general fatigue, leg fatigue, and being winded and overheated at both 3% and 4% dehydration.

“Players should be advised to implement adequate pre-game and in-game hydration strategies to prevent 2% or greater dehydration and its detrimental impact on basketball performance,” the researchers concluded. There were no performance differences between trials using the carbohydrate-enriched drink and the water-electrolyte drink.

“These are important findings,” commented Dr. Michael Mundy, a chiropractor who works with athletes and is also a coach. “Especially in light of previous research showing that athletes—from children to professionals—don’t stay hydrated during practices and games. The hope of better performance might be an incentive to try harder to drink enough electrolyte-rich fluids.”

(Med Sci Sports Exerc 2007;39:1114–23)

Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.

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