Sleep EEG effects of exercise with and without additional body cooling

Abstract

The aim of the study was to help clarify the equivocal findings with slow wave sleep (SWS) stages 3 and 4, following running in physically trained individuals. Six females (22-24 years) ran at 75% of their VO2max for 2 X 40 min periods on two separate occasions, 14.30-17.30 h: once under hot conditions, causing a rectal temperature (Tr) increase averaging 2.3 degrees C, and once with additional cooling, reducing the Tr rise to an average of 1.0 degree C. Compared with baseline nights, no significant sleep effects were found on the cool run. However, after the hot run, SWS, particularly stage 4 sleep, showed significant increases, and REM sleep was decreased. It was concluded that body heating effects during running may play a key role in SWS changes, and that additional cooling seems to eliminate any potential SWS increase.