Humidity and sleep: a review on thermal aspect

Abstract

The peripheral humidity detector/detection is not clear though there are comprehensive reports of subjective perception. High relative humidity at ambient temperatures above thermo-neutral zone has deleterious effect on sleep. Humidity affects heat transfer rate by affecting evaporation and thereby disturbing the Tc and Ts dynamics. The effect is discernible across a host of sleep, body temperature, and microclimate indices. A number of hypotheses have been proposed to explain the sleep structure regulation of which circadian–homeostatic interaction model is the most accepted one. Humid heat may affect sleep through homeostatic pathway possibly interfering with adenosine accumulation in basal forebrain and thereby affecting non-rapid eye movement (NREM) sleep switch point. It may also have a circadian element by interfering with thermo-regulatory feedback loop and/or by affecting Ts change input to sleep regulation.

Keywords:

• sleep
• humidity
• temperature
• circadian and homeostatic

Acknowledgements

The work was funded by Indian Council of Medical Research in the form of SRF to Md. Dilshad Manzar and University Grant Commission in the form of Project Fellowship to Mani Sethi. Authors also wish to acknowledge assistance by Bablu, an architect with diagram work.