Purpose: The purpose of the present study was to investigate the effects of timing of bathing on sleep. Methods: Data were obtained under three conditions of bathing (10 minutes in water of 40℃, body immersion up to neck) performed at 30 minutes, 1 hour and 2 hours before lying down to sleep. Polysomnographic data (EEG, EMG, EOG, and ECG) were recorded during sleep. Temperature of external auditory canal was measured before and after bathing and sleep. Sleep polygraphs were analyzed at every 20-second epoch interval according to the standard criteria of Rechtschaffen and Kales. The low frequency (LF:0.04-0.15Hz) and high frequency (HF:0.15-0.4Hz) components of heart rate variability (HRV), and LF/HF ratio of each five minutes from 22:00 to wake up were calculated from the power spectral analysis of R-R intervals. In addition, subjective feelings for sleep were assessed with Oguri-Shirakawa-Azumi (OSA) sleep profile answered by the participants immediately upon awakening…
bathing time
sleep polysomnograms
heart rate variability
external auditory canal temperature
sleep feelings