Heat loss from the head in cold weather

7 January 2009

In exposing the "myth" that 40 -50% of body heat is lost through the head in cold weather (1) the authors conclude that the body should be protected but that it is a matter of individual preference whether or not to cover the head. This appears to be too cavalier a statement to go unchallenged, particularly in the case of elderly people exposed to cold weather conditions. As the main channel of convective and radiant heat loss when the body is well insulated, exposure of the head and face can account for a large proportion of body heat loss. It is, of course, a different matter when the body and head are immersed in water, as in the experiments quoted, when a measured 10% of total surface heat loss occurs from the head. The claim that there is nothing special about the head in heat balance ignores the important influence of facial cooling in air on systemic cardiovascular reflex responses (2) and that body temperature can be selectively influenced by cooling of the head and face. Covering these areas with hat and muffler in cold weather should remain part of the recommendations designed to help reduce winter morbidity and mortality.

1 Vreeman R, Carroll A. Seasonal medical myths that lack convincing evidence. BMJ 2008 ; 337 : a2769 (20-27 December).

2. Collins KJ, Abdel-Rahman TA, Easton JC, Sacco P, Ison J, Dore C. Effects of facial cooling on elderly and young subjects : interaction with breath-holding and lower body negative pressure. Clin Sci 1996 ; 90 : 485 - 492.

Competing interests: None declared

Competing interests: None declared

Kenneth J Collins, Clinical physiologist

Guildford GU1 2BU

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