By Loraine Ritchey
The following is an article written by Bill Weaver and appears with his permission
PREPARING DANCERS FOR COMPETITION ON HOT WEATHER
by Bill Weaver
After spending the past weekend in Dallas, Texas where the temperature reached the upper nineties and the heat index soared to 118º F, I thought it might be a good idea to write an article about exercising in hot weather. Specific steps should be taken to prepare dancers for training and competing in hot weather. Proper preparation can improve the dancers performance and reduce the potential for heat illness. Under adverse climatic conditions, including high temperature and humidity, heat gained from the combination of physical exertion and the hot environment can exceed the bodies ability to remove heat through perspiration. In instances such as these, heat cramps, heat exhaustion and heat stroke may occur as a result of dehydration and elevated body temperature. These thermal injuries can occur regardless of the dancer's physical condition or ability to adapt to hot weather and can be very dangerous.
HOW THE BODY HANDLES EXCESSIVE HEAT DURING EXERCISE
During exercise, heat produced by working muscles exceeds the amount of heat released by the body causing the body temperature to rise. The rise in body temperature causes an increase in sweating and blood flow to the skin. As a result, heat is removed by evaporation of sweat from the skin, radiated from the body to the cooler surroundings, and is lost by convection to moving air (e.g. wind chill). When the rate at which heat is produced during exercise equals the rate at which heat is lost from the body, the body temperature will plateau at an elevated level. However, when more heat is produced than the body can lose, body temperature will rise to a potentially dangerous level. High environmental temperatures and humidity contribute to the risk of thermal injury because they reduce the body's ability to remove heat. Dancers who are untrained and unacclimatized (not accustomed to the heat) can maintain an elevated, but safe, body temperature during moderated exercise in temperatures ranging from 50º to 85º F. With proper training and heat acclimatization, dancers can safely increase the intensity and duration of exercise in even hotter environments. There is less chance that under hot, humid weather conditions thermal injury will occur in competitive events lasting up to 10 minutes. But, body temperatures could rise to dangerous levels (e.g. 106º f) under these conditions during exercise lasting 12 to 15 minutes or longer. This could easily apply to many dancers who routinely warm up a good 10 to 15 minutes prior to their dances at our outdoor competitions.
HOW TO ACCLIMATIZE YOUR DANCERS
Dancers can acclimatize their bodies to excessive heat and humidity by performing mild to moderate exercise in a hot environment. After 1½ hours to 4 hours of exercise per day for 5 to 15 days, the body will adjust (acclimate) to hot and humid weather conditions. Successful heat acclimatization results in: (1) a lower resting body temperature, (2) lower skin and core temperature during exercise, (3) decreased exercise heart rate and metabolism, and (4) increased sweating and evaporating cooling. All of these changes help dancers safely improve their performance in hot weather. The acclimatization process is similar in men and women, is not affected by the menstrual cycle and does not seem to be affected by age. Training and acclimatization enable dancers to exercise at considerably greater exercise intensities while maintaining safe body temperatures. Both training and heat acclimatization are required for an optimal ability to exercise in the heat.
HOW TO PREVENT THERMAL INJURIES
In preparing for outdoor competitions in hot, humid conditions, warm up in the shade to avoid raising the body temperature too high too soon.
Rest in the shade between dances. Exposure to the sun can cause blood to accumulate in the skin making it less available to working muscles during subsequent exercise/dances.
At competitions between dances and while warming up until you have to get dressed to dance, wear minimal, loose-fitting clothing to help promote heat loss.
During prolonged exercise in the heat (i.e. a full day at an outdoor competition), body fluids that are lost as sweat must be replaced as frequently as possible to avoid dehydration and subsequent thermal injury. Drinking 12 to 20 ounces (1½ to 2½ cups) of fluid 10 to 20 minutes PRIOR to competition is a good idea, but this should not take the place of taking in fluids DURING exercise.
Although water is adequate, fluids you take in during exercise should contain 5% to 8% carbohydrate and a small amount of electrolytes. These beverages (i.e. Gatorade, Powerade, etc.) will provide a source of fuel for the working muscles and will help with the absorption of water and glucose from the intestines. Carbonated soft drinks such as "Coke" are not adequate as fluid replacements.
Throughout heavy work or prolonged exercise, (i.e. lessons, practice sessions, etc.), at least 8 oz. Of fluid should be consumed every 15 to 20 minutes.
The "pre-season" regimen for competitions under hot and/or humid conditions should be preceded by 1 to 2 weeks of conditioning. This means working 1 to 2 hours per day in the heat while wearing minimal clothing and drinking liberally. This will help dancers gradually achieve heat acclimatization.
Practice sessions under very hot, humid conditions should be limited to very moderate workouts or be cancelled.
Dancers who typically train and compete in cool weather, but are scheduled to compete in the heat can greatly improve their heat tolerance by practicing in excess clothing. Carefully supervised, the use of this practice will simulate a warm environment and improve the heat acclimatization process. Similar to exercise in warm weather, frequent fluid consumption is a must during this type of exercise.
Applying proper precautionary steps prior to and during exercise can help dancers avoid thermal injuries. Techniques such as warming up in the shade, drinking adequate type and amounts of fluids and wearing loose fitting clothing can safeguard dancers' health and maximize their performance.
As always for Questions and Comments, I can be reached at
Loraine Ritchey, 1127.W. 4th Street, Lorain, Ohio, 44052.