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HEAT ILLNESS
GUIDE TO HEAT ILLNESS
by: Jacqueline R. Berning, PH.D., R.D.
Fluid replacement is an important nutritional concern for football players. Approximately 60% of body weight is water.
Football Gear Is For Protection Not Cooling,
As a football player trains and competes, fluid is lost through the skin as sweat, through the lungs as he breathes and as urine. If fluid is not replaced at regular intervals during a game or training it can quickly lead to dehydration.
Football players are at increased risk of dehydration in part because of their equipment needs. Football gear is designed for protection, but the necessary padding does not allow for quick evaporation or cooling. It's not uncommon for players to lose anywhere between 5-15 pounds during a game or workout, especially during two-a-day practices.
In addition, a player's helmet substantially reduces the body's ability to release heat, thus increasing body temperature and the risk of heat illness. Players that are dehydrated will fatigue earlier, lose coordination skills and have a higher risk of heat exhaustion, heat illness or even heat stroke. If a football player wants to maximize his athletic potential he should make sure that he is well-hydrated throughout the game or practice.
What Fluids Should Players Consume?
Research shows that a sports drink containing 6% carbohydrate (14g/8 oz serving) can be absorbed in the body as rapidly as water. But unlike water, a sports drink can provide energy to the working muscles, delay fatigue and improve performance. Players that consume a sports drink can maintain higher energy levels at a time when energy stores are becoming depleted. Players who dilute sports drinks don't get enough carbohydrate to maintain energy levels. Also, drinking beverages that have a high carbohydrate level, like soft drinks and some fruit juices, can slow fluid absorption.
Don't Wait Until You're Thirsty
Thirst mechanisms don't kick in until a player has lost about 2% of his body weight as sweat. In other words, a defensive player who weighs 250 pounds may lose 5 pounds before he even becomes thirsty. Unfortunately, this small amount of fluid loss can hurt performance skills and the player may be fatigued before he starts to drink!
Players often drink to quench their mouth thirst. If a player only drinks to quench his thirst he may be replacing only 1/2 to 2/3 of the fluids lost. As a result, he will start the next practice or workout in a state of dehydration. Football players need to drink throughout the day whether they are thirsty or not.
Research shows that a sports drink containing 6% carbohydrate can be absorbed in the body as rapidly as water. But unlike water, a sports drink can provide energy to the working muscles, delay fatigue and improve performance.
Fluid Intake Recommendations
Players should have unlimited access to fluids (sports drinks and water) throughout the game or workout.
Weigh players before and after practice. For each pound lost during the workout, an athlete should consume at least 20 oz of fluid. If this recommended amount of fluid isn't consumed, the player must replace 80% of lost weight by next practice to avoid dehydration.
Check the color of the urine. If it is a dark, gold color (like apple juice) the player is already slightly dehydrated. If it is very pale yellow (like lemonade) then he is on the way to being hydrated.
Players should consume 17-20 oz of fluid two hours prior to the start of the game or workout.
Players should drink during exerxise to minimize losses in body weight but should not over drink.
Avoid carbonated drinks. They can cause bloating and may decrease the amount of fluid consumed.
Avoid caffeinated beverages and alcohol as they cause the body to lose body fluids.
Reprinted with permission from the Gatorade Sports Science Institute.
JACQUELINE R. BERNING, PH.D., R.D., is assistant professor at the University of Colorado (Colo. Springs, CO) and sports nutrition consultant for the Denver Broncos football team.
Hot Weather Exercise Tips
Content provided by Professional Team Physicians
Though football is considered an autumn and winter sport, workouts and practices begin in the peak of summer. Every year there are players, from professionals to school-age, who suffer heat-induced illnesses during summertime football practices. It is therefore essential that players and coaches be knowledgeable about the effects of hot weather on the body, how to avoid heat-induced illnesses, and how to recognize symptoms.
In hot weather, blood travels to your skin to diffuse body heat. As a result, less blood is available to your muscles. Your heart rate during sports and any other activity is going to be higher. To compensate for this, you should reduce the intensity of your exercise. This will keep your heart rate within reasonable limits.
If you are running, limit your routine when the temperature reaches 8085 degrees and when humidity is high. Move your exercise or sports activities indoors to avoid the heat of the day. You can also work out in the early morning or later in the afternoon when it is cooler outside.
If you change locations and start exercising in high altitudes or temperature extremes, slow down your routine. It takes four to six weeks for your body to adjust to a new environment.
Even though it is warm outside and you may feel loose, make sure you go through a warmup. Do not forget to stretch.
If you become dizzy or lightheaded during exercise, stop immediately. Keep yourself hydrated. Dehydration is the leading cause of cramps, especially in your legs. It can also increase your blood pressure and heart rate.
HEATINDUCED ILLNESS
Heat exhaustion is caused by dehydration. Symptoms include chills, lightheadedness, dizziness, headache, sweating, and nausea. If you feel any of these symptoms, stop activity immediately. Get out of the heat to a cool, shaded area. Drink tepid, not cold fluids. If symptoms persist, call your doctor.
Heat stroke is caused by a failure of the body's thermoregulatory system. Heat stroke may be fatal. Symptoms are similar to heat exhaustion, but may progress to more serious neurological symptoms such as disorientation, loss of consciousness, and ultimately seizures. Seek medical help immediately.
HOW TO AVOID HEAT ILLNESS
Keep yourself hydrated. Drink fluids 30 minutes before exercise. During exercise, drink fluids every 15 minutes. After exercise, drink more fluids.
Acclimatize yourself. Build up your tolerance for exercising in warmer and more humid weather. Wear lightweight clothes that let your body's perspiration evaporate to cool you.
Stay fit. Your tolerance for heat increases with fitness. Keep track of medical conditions. Your health and the medications that you take may affect your tolerance to heat. Be especially careful if you are overweight or have heart problems, diabetes, or high blood pressure
Precautions for Healthy Training
Content provided by Professional Team Physicians
By WILLIAM E. STRAW, M.D.
Heat illness generally falls into three progressively more serious categories: heat (or muscle) cramps, heat exhaustion, and heat stroke. There is overlap between the three; for example, cramps can be present in all three forms of heat illness. Heat cramps usually affect the lower legs and abdominal muscles.
CAUSES
Heat illness is caused by an imbalance between water and electrolytes (such as sodium, potassium, and calcium). Another cause of muscle cramps is the buildup of lactic acid in the muscle that can occur during strenuous exercise.
Heat exhaustion occurs when the body's cooling system (mainly perspiration) is unable to keep up with heat stress. Without treatment, this condition can soon progress to heat stroke.
Heat stroke is a medical emergency in which the body's cooling systems suddenly shut down. It can lead to severe dehydration and hyperthermia (a dangerous elevation of body temperature) which can cause damage to the brain and other organs.
Heat stroke can be fatal if not treated quickly by health-care professionals. Young children, senior citizens and those in poor general health are especially susceptible to heat illnesses.
SYMPTOMS
If the humidity is high when temperatures are extreme, perspiration does not evaporate well, if at all, and that has a negative effect on controlling body temperature. If exposure to heat and humidity continues, you may become confused and may stop perspiring. This is a danger sign that urgent medical assistance is necessary.
It is easy to misinterpret the signs of heat illness because dehydration and hyperthermia may interfere with logical thinking. Sometimes it is difficult to remember whether it is worse to have excessive sweating or to have a shutdown in the body's sweating mechanism.
When you get dehydrated, there is not enough blood flow to the leg muscles, and the muscles' balance of water and electrolytes (salts) is upset, so the muscles tighten up into a cramp, usually affecting the lower legs and abdominal muscles.
Symptoms of heat exhaustion include heavy perspiration, skin that may be cool and pale or flushed, headache, dizziness, elevated temperature, rapid pulse, nausea and vomiting, weakness, bright yellow (concentrated) urine or inability to urinate, and sometimes unconsciousness.
In the case of heat stroke, the body temperature climbs to more than 104 degrees, perspiration stops, the skin becomes warm, the pulse is rapid, and breathing is shallow. The athlete may become disoriented, lose consciousness, and suffer irregular heartbeat or cardiac arrest.
TREATMENT
Treatment of heat-related muscle cramps associated with heat exhaustion includes ceasing strenuous activity and retreating to a cooler place; stretching and then massaging of afflicted muscle groups, followed by icing; and replenishment of fluids with water, sports drink, or fruit juice.
For heat exhaustion, treatments include immediate relocation to a cool place; removal of excess clothing; sponging or sprinkling the body with cool water, and copious replenishment of fluids. Medical assistance may be required.
For heat stroke, immediate treatments include either cool baths or ice packs near large arteries such as at the neck and armpits, and oral or intravenous replenishment of fluids. If in doubt, seek urgent medical assistance. Heat stroke is a medical emergency.
PREVENTION
The most important thing to do when having to exercise on a hot, humid day is to drink plenty of fluids. You cannot rely on your body's thirst-feedback mechanism to know how much to drink. If you are in a low humidity area, when you perspire, it will help you cool off more, so you can tolerate higher temperatures better in a dry climate.
You need to drink about a quart of fluid for every pound of body fluid you lose during exercise. Drink water at least every 15 minutes on hot, humid days.
Try to plan your activities early in the morning or late in the afternoon to avoid exposure during the hottest hours of the day. Know when to say "no" to exercise.
You should be drinking enough water so that your urine is light-colored and not dark yellow. That can be an indicator of your level of hydration. Because caffeine and alcohol can cause you to lose extra fluid, they should be avoided.
Wearing a hat or sun visor, particularly one that can "breathe," helps protect you from the effects of direct sunlight. A football helmet is not designed for heat loss. You should also try to wear loose-fitting clothing made from a breathable material, such as cotton, and go for light colors, which do not absorb as much sunlight.
Athletes in stadiums, especially those with artificial-turf surfaces, are even more susceptible to heat illness. Because much body heat is lost through the head, pouring cool water over the head and scalp can promote heat loss and help prevent heat injury.
William E. Straw, M.D. is a member of Professional Team Physicians.
Disclaimer:
The information, including opinions and recommendations, contained in this website is for educational purposes only. Such information is not intended to be a substitute for professional medical advice, diagnosis or treatment. No one should act upon any information provided in this website without first seeking medical advice from a qualified medical physician
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