By: Dr. Terry Weyman

It’s HOT. With the heat, talks of dehydration and heat related illness come to the headlines. Southern California’s hot fall football games, firefighters working the fires, cycling and Triathlons, Fall Motocross races, soccer games and other fall sports. To stay safe you need to understand and comprehend water intake and the requirements each body has to function on a normal level. In the news several months ago, there was a report about 10 people who were taken to the hospital for heat related illness at a rock concert over the weekend. With the fires blazing last week, firefighters need to maintain a high level of fluid intake to maintain body function. Body water and athletic performance are directly connected, and when understood, can be the difference between a winning performance and or/ survival.

Your body needs about 1 ml of water for every calorie that you expend. For example, if you burn 4,000 to 5,000 calories per day (moderate to aggressive athletic workouts), you would need between 4 to 5 liters of fluid to replace what was lost and to keep the biochemistry in proper balance. Monitoring body weight before and after training is the best way to keep up with your body’s fluid needs, which sweating increases. If you don’t believe that hydration can affect athletic performance ask Lance Armstrong. He lost 15 lbs due to dehydration following the first time trial of the Tour de France in 2002 and suffered the next few days more than usual.

Although a 2% weight loss due to dehydration may not cause any “symptoms”, it does decrease physical and mental performance.

Water Loss as % of Body Weight
2% – Difficulty in controlling normal body temperature
3% – Reduced muscular endurance time
4%-6% – Reduced strength, power, endurance and heat cramps
6% – Severe heat cramps, heat exhaustion and heat stroke

During exercise, especially in the heat, some of the water that naturally circulates through your body is used by your sweat glands. Inadequate fluid balance can result in a chain reaction that can be severely detrimental to your health. The first step in this reaction is a decrease in blood volume, which increases the heart rate in an attempt to get the fluids to the vital organs. The body’s next reaction is to constrict the blood vessels in order to maintain proper blood pressure. However, this reaction will cause the body temperature to rise due to the heat produced by the working muscles which can’t be transported to the skin’s surface. This leads to heat illnesses such as heat cramps, exhaustion and heat stroke.

To avoid this chain reaction you must stay properly hydrated during your exercise. The recommended fluid intake for exercise or training is 8 to 12 ounces fifteen minutes before you begin your exercises. During your training, drink 4-6 ounces every 10 to 15 minutes. After you have completed your training, you should consume 16 ounces for every pound lost (weigh yourself before and after exercise to determine weight loss). If you are working out longer than 60 minutes, a sports drink may be helpful in delaying fatigue by providing additional energy for working muscles. It will also be helpful in the overall chemistry balance since it will be replacing needed electrolytes that are lost during the sweating process. A 5 to 8% concentration of carbohydrates (as seen in most sports drinks) has been shown to be absorbed quickly. The small amount of electrolytes can also aid in the absorption of water from the intestines. A great product on the market for electrolyte replacement is a powder called Endura, made by a company called Metagenics. You can find this product at some bike shops or at health care facilities. Remember, this simple equation. First hour, water only. Second hour a mix of water and sport drink, third hour sport drink (electrolyte replacement). Due to the salts and sugars in the sports drinks, drinking too early can clog the sodium and calcium channels causing the athlete to go into a state of early dehydration. You can also increase the risks of cramping by drinking a sport drink too early.

With the heat of the summer here, be smart in your training. Do not exercise during the hottest times of the day (10-3), stay hydrated and properly warm up and cool down. To avoid heat illness and decrease your overall performance, remember this: an athlete should never be thirsty!

Dr. Terry Weyman is the clinic Director for the Chiropractic Sports Institute. All the Doctors at CSI specialize in the care of the active person. For further information they can be contacted at www.gotcsi.com