Is it necessary for athletes to drink fluids during exercise, or will this fluid cause the athlete to "drag," that is, not to perform as well ? Restricting fluids during exercise could actually cause a DECREASE in the athlete's performance, and could cause serious medical problems to an athlete. Some investigators have found that having the athlete drink fluids before exercise and during exercise can actually IMPROVE the athletes performance.
Fluid replacement is very important for athletes. An eighteen year old who is not vigorously exercising needs approximately 2.5 quarts of replacement water every day. This is needed to replace water excreted via urine (1.3 quarts), the skin (0.85 quart by perspiration), and the lungs (0.35 quarts by exhaled air). To replace this water, the average individual consumes a minimum of 1.2 quarts (38 ounces or five glasses) of fluid each day, and an additional
1.0 quarts in foods, such as fruits and vegetables, which contain large amounts of water. In addition, 0.3 quarts of water is formed when food molecules are degraded for energy. With vigorous exercise, there will be an increase in the loss of fluid from the skin (from up to 3.0 to 5.0 quarts) and from the lungs (up to 0.7 quarts). This increased loss of water will make the player dehydrated unless replaced; the athlete needs to drink several quarts of water to prevent dehydration.
During exercise, the body works hard at performing, which produces a large amount of heat internally. The core temperature of the body rises, and there is a need for the body to dissipate this additional heat. The major way that the body handles this additional heat is by sweating and evaporation of perspiration from the skin. Also, players lose additional water during exercise from exhaled air in the lungs. The body can react unfavorably to fluid lose. An athlete can experience early muscle fatigue, loss of coordination, irritability, and a inability to perform at an appropriate level if he/she becomes dehydrated.
How, when, and with what should this water be replaced ?
The thirst mechanism is triggered by an abnormally high concentration of salt (sodium) in the blood, which can result when you sweat. As you sweat, you lose water from the blood. The remaining blood becomes more concentrated and has a high salt (sodium) level. This triggers the thirst mechanism and increases your desire to drink. To quench your thirst, you drink water and other fluids to decrease the blood concentration of salt (sodium). However, this thirst mechanism does not always work early enough for athletes undergoing strenuous exercise. If an athlete waits until the thirst mechanism kicks in, the player is probably already dehydrated. Water replacement should start before the game or practice, continued during the activity, and include post activity hydration.
Plain water, preferably cold, is the best fluid replacement. Cold water leaves the stomach faster than warm water, and will decrease bloating. Plain water leaves the stomach much faster than drinks containing glucose (sugar), such as Coca Cola, Pepsi, Gatorade or Exceed. The purpose of hydration in sports is to get water to the working muscles and cells as soon as possible.
During exercise lasting less than ninety minutes, there is no evidence that a carbohydrate-electrolyte drink (such as Gatorade) is any better than plain water.
In addition to the fact that sugared drinks leave the stomach slower than plain water, players should avoid highly sugared drinks (greater than 5% glucose) and chocolate bars within one hour of a game or practice for another reason. This sugar load will cause the body to secrete a hormone (insulin) that will actually cause a decrease in the blood level of carbohydrate about thirty to forty minutes after the ingestion of the sugar. This decrease in the blood level of carbohydrate can cause the players to experience a sluggish feeling when they step out on the playing field or ice surface.
Water is a must during games and practices. Players should have their own water bottles, to eliminate the risk for spreading communicable disease. Also, the water bottle should be held in some sort of receptacle that prevents the bottle from falling on the floor and becoming contaminated.
Drinking water before a game or practice, even cold water, will not cause cramps. In fact, there is a good possibility that cramps can result from
dehydration due to drinking to little water.
The American College of Sports Medicine recommends drinking about two glasses (17 ounces) of fluid two hours before the scheduled game or practice. During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace the water lost through sweating and exhaled air. In a practice this could be two to four ounces (a half glass) of water every five to ten minutes, or, in an ice hockey game, two to four ounces every shift.
Nancy Clarke's Sports Nutrition Guidebook: Eating to Fuel your Active Lifestyle by Nancy Clark (see Chapter 10 Fluid Facts for Thirsty Athletes)
Champaign, IL, Leisure Press, 1990
Exercise Physiology; Energy, Nutrition, and Human Performance (Fourth Edition) by William D. McArdle, Frank I. Katch, and Victor L. Katch
Baltimore, MD, William & Wilkins, 1991
Hockey Fitness: Year-Round Conditioning On and Off the Ice
by Don MacAdam and Gail Reynolds,
Champaign, IL, Leisure Press 1988
Keeping Young Athletes Healthy: What Every Parent and Volunteer Coach Should Know by Alan R. Figelman and Patrick Young
New York, Simon & Schuster, 1991
Injury Prevention through Fluid Replacement: by Jeffrey Klein Article in Chalk Talk, A Monthly Newsletter for Hockey Coaches, October 1996
1036 Washington, Dearborn, MI 48124 (313) 730-1110
Exercise and Fluid Replacement
American College of Sports Medicine
Position Stand on Exercise and Fluid Replacement
in Med. Sci. Sports Exercise., 28:1, 1995, pp 1-7.