SOME LIKE IT HOT!

Some do like it hot. Heat, however, takes its toll on the body. In the heat of summer, it is particularly important to pay attention to good hydration.

July 16, 2002, Warrenville, IL - The following are some answers to common questions about hydration during the summer months.

Why is adequate hydration important?
Sweating is the primary means of cooling the body, which is very important during the hot summer months. When someone is dehydrated, sweating is less effective, possibly allowing a rise in core body temperature. This could lead to heat-related illnesses, such as heat exhaustion and the more dangerious heat stroke. In addition, it is known that an individual cannot athletically perform at the highest level in the dehydrated state.

How much water do I need?
The average adult needs 2-3 liters of fluid per day. These requirements are greatly increased during athletic activity. The best approach is to be well hydrated before athletic activity. One simple guideline is that an athlete's urine should be pale yellow or nearly clear prior to activity. Also, it is recommended that an athlete consume 16-20 ounces of water about 2 hours before exercise, and 4-8 ounces for every 15 minutes of activity.

Can't I just drink when I'm thirsty?
No. The body is already mildly dehydrated when you are thirsty, and it may be difficult by that time to consume enough fluid to catch up.

What should I drink? Should I use sports drinks?
Water is the best fluid to consume. Soda and fruit drinks should be avoided during athletic activity, mainly because they are difficult to digest during physical exertion and may upset the stomach. Sports drinks are fine, and may have the added benefit of enhanced consumption because of their flavor. Sports drinks are recommended for continuous physical exertion that lasts longer than one hour, mainly because the carbohydrate content in the drink provides a good source of energy. For most situations, though, water is the best liquid to choose.

What are electrolytes?
Electrolytes are the "salts" in the blood, primarily sodium, potassium and chloride. They are essential for the proper functioning of all systems in the body. Electrolytes are lost through sweating, but proportionately less than water. Severe abnormalities in electrolytes concentrations are significant medical situations, but rarely occur except in strenuous endurance events, such as marathons and triathlons. Virtually all Americans consume enough electrolytes in their diets, and do not need to worry about electrolyte replacement during modest to moderate exercise.

Can I drink too much water?
Yes. This is relatively rare but can occur. Loss of salts while sweating, combined with an enormous fluid intake, can lead to a dangerously low concentration of sodium in the blood, which at the extreme can lead to seizures or death. This typically only occurs during strenuous endurance events when the athlete has been competing for over 4 hours and has had excessive sweating and/or and inordinate amount of water intake.

Does drinking water cause cramps during physical activity?
No. The cause of cramping is not fully understood, and is likely a combination of many factors. Cramps are mostly associated with muscle fatigue in combination with poor stretching habits. Dehydration and electrolyte disturbances can play a role, however, so it is recommended that an athlete maintain an adequate hydration and nutrition status.

Which is worse, the heat or humidity?
Both play a role in dehydration and heat illnesses. The hotter the ambient temperature, the more the body needs to sweat to keep cool, and dehydration can occur. When it is very humid, the sweating mechanism for cooling is not as efficient, and a rise in core body temperature could occur. Hot and humid weather together therefore can be a dangerious combination. Hot, dry weather can be a problem as well, since sweat evaporation occurs easily and the athlete may not be aware of the level of fluid loss.

In summary, remember that adequate hydration is important at all times, but especially during the active summer months. Drink water before activities, and drink small amounts consistently during prolonged activity. Don't rely on the sensation of thirst, as this occurs after mile dehydration has already set in. Be careful during hot, sunny days, and wear loose, breathable clothing that allows sweating to occur. Don't over-exert yourself, and be mindful of symptoms such as fatigue. Follow these simple guidelines for proper hydration, and enjoy the summer and all the sports and other activities it has to offer.

This material was prepared by Matthew D. Gimre, M.D., orthopaedic medicine and sports medicine specialist at OAD Orthopaedics, Ltd. With offices in Warrenville, Wheaton, Naperville and Carol Stream, OAD Orthopaedics is a comprehensive orthopaedic and sports medicine practice. For further information, call (630) 225-BONE(2663).

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