The most common signs and symptoms of heat exhaustion include:
- Dark-colored urine (a sign of dehydration)
- Muscle or abdominal cramps
- Nausea, vomiting, or diarrhea
- Pale skin
- Profuse sweating
- Rapid heartbeat
If you need medical attention due to heat exhaustion, it may be apparent to medical personnel that you have heat exhaustion, or they may take your temperature to confirm the diagnosis and rule out heatstroke. If your doctors suspect your heat exhaustion may have progressed to heatstroke, you may need additional tests, including:
- A blood test to check for low blood sodium or potassium and the content of gases in your blood
- A urine test to check the concentration and composition of your urine and to check your kidney function, which can be affected by heatstroke
- Muscle function tests to check for rhabdomyolysis — serious damage to your muscle tissue
- Imaging tests to check for damage to your internal organs
When the heat index is high, stay indoors in air-conditioned areas when possible. If you must go outside, take the following precautions:
- Wear lightweight, light-colored, loose-fitting clothing.
- Protect yourself from the sun by wearing a hat or using an umbrella.
- Use sunscreen with a sun protection factor (SPF) of 15 or more.
- Drink plenty of water before starting an outdoor activity. Drink extra water all day. Keep in mind that heat-related illnesses are not only caused by high temperatures and a loss of fluids, but also a lack of salt in the body. Some sports drinks can help replenish the salt in your body lost through sweating.
- Drink fewer beverages that contain caffeine (such as tea, coffee and soda) or alcohol.
- Schedule vigorous outdoor activities for cooler times of the day -- before 10:00 a.m. and after 6:00 p.m.
- During an outdoor activity, take frequent breaks. Drink water or other fluids every 15 to 20 minutes, even if you don't feel thirsty. If you have clear, pale urine, you are probably drinking enough fluids. Dark-colored urine is an indication that you're dehydrated.
- If you have a chronic medical problem, ask your doctor about how to deal with the heat, about drinking extra fluids and about your medicines.