Exercise heart rate response to facial cooling.

The heart rate responses of physically untrained men to exercise with and without facial cooling were determined. Cold wind (10 degrees C, 6.5 m x s-1, or 2 degrees C, 6.5 m x s-1) was directed at the faces of the subjects during a 16 min bout of progressively intense exercise. The 10 degrees C wind resulted in a significantly (p less than 0.05) lowering of heart rate that appeared to be associated with a decline in forehead temperature at 4, 6, and 8 min of exercise. No differences were observed for blood pressure or rectal temperature. The significant (p less than 0.05) reduction in heart rate with the 2 degrees C cold wind did not appear to be associated with changes in facial temperature. The 2 degrees C wind also resulted in a persistent peripheral vasoconstriction (p less than 0.05). The results suggest that the heart rate response to facial cooling during exercise is mediated not through a reflex associated with increased stroke volume but rather via a central thermoregulatory response.