The U.S. and most of the world experienced unprecedented heat waves last summer, and this summer promises more of the same. The Northeast is set to experience its first official heat wave as I write. Extreme heat can cause serious health issues, including death, so prepare – prevention is much better than treatment.
The body is generally quite good at maintaining a normal internal (or “core”) temperature. We get rid of excess heat by increasing blood flow to the skin, where it can be removed by air flowing over us and by increasing sweating, which dissipates heat as it evaporates.
In extreme heat conditions, these mechanisms may be inadequate, and our core body temperature rises. The heart feels the stress – it works much harder trying to push more blood through dilated blood vessels.
The first sign of heat beyond the body’s ability to cope are cramps and “heat exhaustion”: dizziness, weakness, nausea, headache and an unsteady gait. If the sufferer is moved to a cool environment, these symptoms will usually pass.
If the core body temperature exceeds 104 (40C), you may go on to experience “heat stroke.” This life-threatening condition begins with confusion and can go on to seizures, delirium, coma and death if untreated.
While everyone can experience these heat-related emergencies, certain people are at higher risk: children and the elderly, those doing physical work outdoors and those taking medications that impair the body’s response to heat (such as diuretics – fluid pills – many psychiatric drugs and anticholinergics, used for some urinary and bowel problems).
How can you prevent heat-related illness? The most obvious is the most important: Stay cool! Keep blinds down to lessen indoor heat; use your air conditioner, and if only 1 or 2 rooms have AC, stay in those rooms. If you do not have AC, use public places that do, such as the library or official cooling sites.
Avoid doing physical work in the heat of the day; if you must run or cycle, do it in the early morning. Hydrate! You are going to lose water by increased sweating, so push the water and electrolyte drinks.
If you are experiencing any of the symptoms noted above, stop physical activities and get to somewhere cool. If you do not improve, call 911. An emergency home remedy is to get in a cold tub or to put ice bags under the armpits, behind the neck and in the groin.
Check on any neighbors who may be at risk. Since an early sign of heat-related illness is confusion, they may not react properly.
Edward Hoffer MD is Associate Professor of Medicine, part-time, at Harvard.
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