Pay attention to warning signs
During hot-weather exercise, watch for signs and symptoms of heat-related illness. If you ignore these symptoms, your condition can worsen, resulting in a medical emergency. Signs and symptoms include:
- Muscle cramps
- Nausea or vomiting
If you develop any of these symptoms, you must lower your body temperature and get hydrated. Stop exercising immediately and get out of the heat. If possible, have someone stay with you who can help monitor your condition. Remove extra clothing or sports equipment. Drink fluids — water or a sports drink. If possible, fan your body or wet down your body with cool water. If you don't feel better within 30 minutes, contact your doctor. If you have signs of heatstroke, seek immediate medical help.
Once you've had heatstroke, you're at a higher risk of getting a heat illness again. Get cleared by your doctor before you return to exercise if you've had heatstroke.
How to avoid heat-related illnesses
When you exercise in hot weather, keep these precautions in mind:
- Watch the temperature. Pay attention to weather forecasts and heat alerts. Know what the temperature is expected to be for the duration of your planned outdoor activity.
- Get acclimated. If you're used to exercising indoors or in cooler weather, take it easy at first when you exercise in the heat. As your body adapts to the heat over the course of one to two weeks, gradually increase the length and intensity of your workouts.
- Know your fitness level. If you're unfit or new to exercise, be extra cautious when working out in the heat. Your body may have a lower tolerance to the heat. Reduce your exercise intensity and take frequent breaks.
- Drink plenty of fluids. Dehydration is a key factor in heat illness. Help your body sweat and cool down by staying well hydrated with water. Don't wait until you're thirsty to drink. If you plan to exercise intensely or for longer than one hour, consider a sports drink instead of water. Sports drinks can replace the sodium, chloride and potassium you lose through sweating. Avoid alcoholic drinks because they can actually promote fluid loss.
- Dress appropriately. Lightweight, loosefitting clothing helps sweat evaporate and keeps you cooler. Avoid dark colors, which can absorb heat. If possible, wear a light-colored, wide-brimmed hat.
- Avoid midday sun. Exercise in the morning or evening, when it's likely to be cooler outdoors. If possible, exercise in shady areas — or do a water workout in a pool.
- Wear sunscreen. A sunburn decreases your body's ability to cool itself.
- Have a backup plan. If you're concerned about the heat or humidity, stay indoors. Work out at the gym, walk laps inside the mall or climb stairs inside an air-conditioned building.
- Understand your medical risks. Certain medical conditions or medications can increase your risk of a heat-related illness. If you plan to exercise in the heat, talk to your doctor about precautions.
Heat-related illnesses are largely preventable. By taking some basic precautions, your exercise routine doesn't have to be sidelined when the heat is on.
Jun. 25, 2011
See more In-depth
- Tips for preventing heat-related illness. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/disasters/extremeheat/heattips.asp. Accessed June 6, 2011.
- Howe AS, et al. Heat-related illness in athletes. American Journal of Sports Medicine. 2007;35:1384.
- Mechem C, et al. Severe hyperthermia (heat stroke) in adults. http://www.uptodate.com/home/index.html. Accessed June 6, 2011.
- Glazer J, et al. Management of heatstroke and heat exhaustion. American Family Physician. 2005;71:2133.
- Gomez J, et al. Environmental stress. In: DeLee JC, et al. DeLee and Drez's Orthopaedic Sports Medicine: Principles and Practice. 3rd ed. Philadelphia, Pa.: Saunders Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-1-4160-3143-7..X0001-2--TOP&isbn=978-1-4160-3143-7&uniqId=230100505-57. Accessed June 6, 2011.
- Laskowski ER (expert opinion). Mayo Clinic, Rochester, Minn. June 13, 2011.