Death in heat waves: Beware of fans...

doi:10.1136/bmj.327.7425.1228-b

BMJ 2003;327:1228 (22 November), doi:10.1136/bmj.327.7425.1228-b

Letter

Death in heat waves

Beware of fans...

The first 150 words of the full text of this article appear below.

EDITOR—In his editorial Keatinge referred to fans as aprevention for heat injury.¹ However, in severe heat, fans canadd to the level of heat stress.

Writing about the fatal heat wave of 1995 in Chicago, the USCenters for Disease Control and Prevention noted that fans shouldnot be used for preventing heat related illness in areas withhigh humidity because increased air movement (such as from fans)is associated with heat stress when the ambient temperatureexceeds approximately 100°F (37.8°C) and because fansare not protective at temperatures greater than 90°F (greaterthan 32.3°C) with humidity greater than 35% (the exact temperaturevaries with the humidity).²

Fans can be extremely effective when combined with the use ofa fine water mist in areas of normal or low humidity, but ifthe temperature and humidity are high, even water mist plusfanning is not reliable for cooling. . . . [Full text of this article]

Robert M Wolfe, assistant professor

Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA r-wolfe@northwestern.edu