Welcome to Dan Riley's latest installment of Texans Fitness Corner. The response continues to be overwhelming. We will continue to post selected answers to your questions throughout the year. Join in by shooting over an e-mail to firstname.lastname@example.org.
NOTE:Before engaging in any new physical activity, always consult your physician.
My wife and I recently visited our oldest son Marty. He works for Microsoft and lives in Redmond, WA, just outside of Seattle. During our visit I was quickly reminded how specific exercise is and how our body adapts to it. For those of you who have visited the Seattle area, you are well aware of how hilly it is there.
I run regularly in Houston. The area where I run is flat. My son lives in a neighborhood that is very hilly. Needless to say my lower legs were very sore the day after my first run.
The soreness was a product of the increased stretch on the calves, and the increased degree of difficulty while running at grade instead of running on a flat surface. After several days of running my body adapted and the soreness was gone. Although it was sunny every day during our visit, the level of humidity was very low.
When I returned to Houston it didn't take long for me to realize the impact heat and humidity have on the body, especially during exercise. The recent tragic deaths of several athletes are an ominous reminder of the need to pay strict attention to the perils of heat related complications.
Athletes aren't the only people susceptible to dehydration and complications with the heat. Young children, over fat people, older adults, and non-acclimatized individuals, are especially vulnerable during hot and humid weather.
There are serious health consequences that can occur with exposure to heat and humidity. The most serious is heat stroke, and heat exhaustion. Muscle cramps are also attributed to fatigue and dehydration. The performance of an athlete is severely affected by a loss of fluids and electrolytes.
The body is primarily composed of water. The human body is approximately 60% water and all systems in the body are dependent upon it. Many athletes (and non-athletes) simply don't drink enough water.
While with the Redskins I took a graduate nutrition class taught by Dr. Pat Mann. She is the former nutrition consultant for the Washington Capitals. She states, "There is no fountain of youth, no magic pill or potion to enhance performance. But there is water." She adds, "Few things cripple athletes faster than dehydration."
You don't need to be in an exhausted state to negatively impact your performance. Dr. Mann states, "A one to two percent drop in body weight due to water loss can cause a 15 percent decrease in performance."
Water is the most powerful substance an athlete can ingest. Many athletes live in an under hydrated state. How do you know if your water intake is adequate? A rule of thumb used is the color of urine. It should be almost clear in color. If it is a bright yellow it's quite possible you aren't drinking enough water.
We encourage our players to drink a minimum of two quarts of water (eight 8 ounce glasses) every day, above and beyond what they sweat. The water shouldn't be gulped at one sitting.
Sweating is one of the four mechanisms we use to help cool the body. It is important to remember that it is not sweating that cools the body. It is the evaporation of sweat that provides the cooling process.
When it is hot and humid it makes it difficult for sweat to evaporate causing us to sweat even more when the humidity is high. About 50 percent of body heat is lost through the head. I tell our players to remove their helmet whenever possible and avoid bandanna's. We suggest exposing any skin that is covered whenever possible. Pull the socks down; take their pads and t-shirt off at half time, etc. None of these suggestions will have any impact if the athlete doesn't drink plenty of fluids. Remember, thirst is not a good indicator of how much water you actually need. Typically people only replace 2/3 of their sweat loss.
The American College of Sports Medicine recommends that athletes should weigh themselves before and after exercising. Water weight lost must be replaced for the athlete to return to a fully hydrated state. A pint of water weighs approximately one pound.
The aging process erodes our perception of thirst needs. Older people should make a conscious effort to drink more to prevent dehydration.
The Gatorade Sports Science Institute has conducted a significant amount of research in the area of dehydration. They are an excellent resource for a wide range of information www.gssiweb.com.
Cramping is another byproduct of dehydration. Insufficient conditioning and fatigue can cause muscle cramps. Profuse and prolonged sweating during ongoing activity can cause heat cramps. Dr. Bob Murray, of the Gatorade Sports Science Institute, has studied cramping in depth.
Their research has determined that most people lose far more sodium than any of the other electrolytes. Drinking plain water may not be adequate to prevent cramping in some people. Athletes that sweat profusely and/or follow a low salt diet, are most prone to cramping.
Athletes who are not acclimatized to the heat generally lose more sodium. This may be a factor why many athletes cramp early in their competitive season. The literature varies on the length of time it takes an athlete to acclimatize. Astrand and Rodahl state, "Within 4 to 7 days exposure to a hot environment most of the changes have taken place, and at the end of 12 to 14 days, the acclimatization is complete."
I called Dr. Murray after reviewing a great deal of literature on the relationship between salt and cramping. I asked Dr. Murray how salt could be the culprit if most of us already consume too much salt in our diet? I also asked why more athletes don't cramp?
He stated it appears to be related to the individual differences in sodium balance in the body. Those who cramp the most sweat more and lose greater amounts of salt in the sweat. It appears that extra salt is necessary when athletes are training in hot conditions for extended periods.
Dr. Michael Bergeron, from the Medical College of Georgia, states, "A loss of just a few grams of sodium can disturb the concentration of sodium around specific nerve endings and muscle fibers and lead to muscle cramps."
During hot weather the Gatorade Sports Science Institute recommends for those athletes especially prone to heat cramps to add additional salt, e.g., ½ teaspoon/32 oz. to their sports drink. Salting their food and eating salty snacks (pretzels) is another method advocated for fending off cramps.
Many athletes are looking for a supplement to give them an edge. My advice is to concentrate on drinking plenty of water. It can have the biggest impact on maximum performance and their well-being.
Astrand, Per-Olof, M.D., Rodahl,Kaare, M.D., Textbook of Work Physiology, McGraw-Hill Book Company, New York, 1970.
Mann, Pat, PhD., Good Hydration, Nautilus Fitness Magazine, Fall, 1995, p. 26-29.
Bergeron, Michael, Ph.D., Sodium: The Forgotten Nutrient, Gatorade Sports Science Institute, Volume 13, Number 3.