The part of your brain called the hypothalamus controls your body temperature. Normal body temperature is 98.6 degrees Fahrenheit. When your body temperature rises above normal, it triggers your body's internal cooling system in the form of perspiration. Prolonged exposure to high temperatures without replenishing the fluids you lose through sweating can lead to heat exhaustion, which in turn can lead to heat stroke, heart attack and death if it's left intreated.
Exercise and Hot Weather
Doing strenuous activity or exercising in hot temperatures puts extra stress on the lungs and heart. The combination of high air temperatures and exercise increases your body temperature. Blood circulates through your skin to dissipate the heat, which decreases the blood supply to your muscles and increases your heart rate. Your body is stressed even more when you exercise in humid weather because sweat does not readily evaporate from your skin, which further elevates your body temperature and increases your risk for heat exhaustion.
Symptoms and Signs
Preventing heat exhaustion requires paying attention to your body when you exercise in hot weather. Symptoms include headache, vomiting or nausea, rapid heartbeat, fatigue, thirst, dizziness or fainting, muscular and abdominal cramping, sweating profusely and clammy, pale skin. If you feel any of these symptoms, immediately stop exercising, get out of the heat, drink water and wet and fan your skin. Seek medical attention if you do not feel better within 60 minutes.
Risk Factors
Factors that increase your risk for heat exhaustion include having respiratory or heart disease or high blood pressure, obesity, being elderly or under age 5, pregnancy, dehydration, chronic illness or disability, drinking alcohol and being on medications that affect the body's ability to cool itself, such as antidepressants or antihistamines.
Diagnosis/Treatment
Treatment primarily involves drinking cool fluids like water or a sports drink containing electrolytes and resting in a cool place, such as an air-conditioned room or a shady area outdoors. Spraying yourself with water and fanning can also help. If your symptoms require medical attention, your doctor will conduct a physical examination, check your temperature, pulse and blood pressure and assess how dehydrated you are. He may also take blood and urine samples. Depending on your symptoms, he may recommend an oral or intravenous saline electrolyte solution.
Prevention
MayoClinic.com advises starting slowly and gradually increasing exercise intensity as your body adapts to the heat. Consult your doctor if you have a chronic medical condition. Drink plenty of fluids as you work out, even if you're not thirsty, and avoid alcoholic or caffeinated drinks. Exercise in the morning or evening when it's cooler outdoors. Wear sunscreen and wear light, loose-fitting clothing in light colors; dark colors absorb heat. You can always choose to work out indoors, like in a gym, if you don't want to work out in the heat.
