Thermoregulatory effects of three different types of head cooling in humans during a mild hyperthermia.

Seven healthy young men participated in six trials with three different types of local cooling [cool air breathing (CAB), face skin cooling (FaC), and combined cooling (CoC)] in a warm environment for 90 min while either resting (operative temperature: T(0) = 40 degrees C, dew point temperature: T(dp) = 15 degrees C, air velocity: v(a) = 0.3 m x s(-1)) or exercising on a cycle ergometer with an external work load of 90 W (T(0) = 36 degrees C, T(dp) = 15 degrees C, v(a) = 0.3 m x s(-1)). Cool air (10 degrees C) arrived at the entry point of the hood and/or the mask at a ventilation rate of 12 m x s(-1). Oesophageal temperature was not affected by any kind of cooling, while tympanic temperature was decreased at rest by both FaC and CoC [respectively -0.15 (0.06) and -0.09 (0.03) degrees C, P