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Purpose

We examined the effect of electric fan use on cardiovascular and thermoregulatory responses of nine young (26±3 years) and nine aged (68±4 years) adults exposed to extreme heat and humidity.

Methods

While resting at a temperature of 42 C, relative humidity increased from 30 to 70% in 2% increments every 5 minutes. On randomized days, the protocol was repeated without or with fan use. Heart rate (HR), core (Tcore) and mean skin (Tsk) temperatures were measured continuously. Whole-body sweat loss (WBSL) was measured from changes in nude body weight. Other measures of cardiovascular (cardiac output), thermoregulatory (local cutaneous and forearm vascular conductance, local sweat rate), and perceptual (thermal and thirst sensations) responses were also examined.

Results

When averaged over the entire protocol, fan use resulted in a small reduction of HR (− 2 beats/min, 95% CI:− 8 to 3 …