Hydration and the Athlete
As we exercise, we produce heat within our body that forces the loss of water primarily through two sources: exhaled vapor and sweat. Anyone who has slept in a tent in Alaska to awake to dripping beads of water can testify to how much water we lose in a simple night of sleep. We can lose up to two liters of water per hour in intense physical activity. We sweat to cool our bodies that have heated up because of the activity.
Dehydration can occur when fluid loss exceeds intake. This water deficit can occur before or during the exercise. Fluid deficits can impair athletic performance, as a decrease in sweating due to lack of fluids will actually cause the core body
to rise. When the radiator runs out of water, the automobile engine cannot be cooled and it overheats. This loss of fluid can cause severe thermoregulation problems, and lead to heat exhaustion or heat stroke.
Heat exhaustion, which presents as weakness and periods of lightheadedness, can be treated with oral fluids, rest, and towel soaks. The more serious heat stroke occurs when the core temperature exceeds a certain level, changes in mental status occur (confusion), and fatigue is noted. A serious inability to urinate is noted as well, and in extreme cases a dark colored urine may be seen. Immediate attention is needed, included cooling the individual and intravenous fluids.
Hypohydration, or the lack of proper fluid intake, can occur when athletes do not voluntarily drink enough fluids prior to and during a given activity. Most do not drink enough prior to the event, and the loss of only 2% body weight has been shown to affect performance. Muscular performance is diminished as well, as strength is lost as well as endurance.
Exercises in the summertime in Alaska will obviously require more fluid intake. Those sports that are indoor, require thick heavy uniforms, and demand high physical output can be causes of fluid dehydration. Athletes should experiment during practice, to determine what they can tolerate to allow them to play without gastric problems.
A good routine for fluid guidelines involve having any athlete drink two cups of fluid two hours before the event. Another cup of either a sports drink or water should be taken about 30 minutes prior to playing. Attention to how much sugar is in the sports drink should be made, as you should avoid those fluids that contain greater than 8% carbohydrates. Avoid fruit drinks prior to, during, and after sports as the fruit sugar, fructose, can cause gastric distress.
There is little science that proves that sugar containing beverages enhance performances that last less than an hour. Longer events however, may require some fluid intake with sugar content of around 8-10%. The carbohydrates obtained from these sugars may improve performance in marathon type events, and these fluids should contain some sodium as well. Significant amounts of sodium are lost in the sweat, and low levels of sodium in the blood are well documented in athletes performing in ultraendurance events.
Fluid intake should be constantly addressed during both winter and summer months. The dry climate we have in Fairbanks will require awareness and close observation of some simple guidelines in order allow one to enjoy his athletic endeavors with peak performance.