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Risk factors
By Mayo Clinic staffAnyone can develop heat exhaustion, but certain factors increase your sensitivity to heat. They include:
- Young age or old age. Infants and children younger than 4 and adults older than 65 are at higher risk of heat exhaustion. The body's ability to regulate its temperature isn't fully developed in the young and may be reduced by illness, medications or other factors in older adults.
- Certain drugs. Medications that affect your body's ability to stay hydrated and respond appropriately to heat include some used to treat high blood pressure and heart problems (beta blockers, diuretics), reduce allergy symptoms (antihistamines), calm you (tranquilizers), or reduce psychiatric symptoms such as delusions (antipsychotics). Additionally, some illegal drugs, such as cocaine, amphetamines and Ecstasy, can increase your core temperature.
- Obesity. Carrying excess weight can affect your body's ability to regulate its temperature and cause your body to retain more heat.
- Sudden temperature changes. If you're not used to the heat, you're more susceptible to heat-related illnesses, such as heat exhaustion. Traveling to a warm climate from a cold one or living in an area that's experienced an early heat wave can put you at risk of a heat-related illness because your body hasn't had a chance to get used to the higher temperatures.
- A high heat index. The heat index is a single temperature value that considers how both the outdoor temperature and humidity make you feel. When the humidity is high, your sweat can't evaporate as easily, and your body has more difficulty cooling itself, making you prone to heat exhaustion and heatstroke. When the heat index is 91 F (33 C) or higher, you should take precautions to keep cool.
References
- Heat injury and heat exhaustion. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00319. Accessed Aug. 17, 2011.
- Extreme heat: A prevention guide to promote your personal health and safety. Centers for Disease Control and Prevention. http://www.bt.cdc.gov/disasters/extremeheat/heat_guide.asp. Accessed Aug. 17, 2011.
- Platt M, et al. Heat illness. In: Marx JA, et al. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa.: Mosby Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-323-05472-0..X0001-1--TOP&isbn=978-0-323-05472-0&uniqId=230100505-57. Accessed Aug. 18, 2011.
- Mechem CC. Severe hyperthermia (heat stroke) in adults. http://www.uptodate.com/home/index.html. Accessed Aug. 18, 2011.
- Mattis JG, et al. Heat stroke: Helping patients keep their cool. Nurse Practitioner. 2011;36:48.
- Using the heat index: A guide for employers. U.S. Department of Labor, Occupational Safety and Health Administration. http://www.osha.gov/SLTC/heatillness/heat_index/index.html. Accessed Aug. 24, 2011.
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