Sleep stage and skin temperature regulation during night-sleep in winter

To clarify the thermally comfortable environment for satisfied sleep, we investigated the relationship between skin temperatures and sleep stages during night-sleep in winter, summer and autumn. Four healthy young females served as the subjects. The experiments were performed in a climate chamber under three conditions: at 13 degrees C-RH70% with futon and blanket in winter, at 20-18 degrees C-RH60% with futon and towelket in autumn and at 29 degrees C-RH70% with towelket in summer. The subjects' skin temperature on the sole was lower until about 4 hours after lights off in winter than in autumn and summer, and the percentage of st.2 was lower and st.4 was higher in winter than in autumn and summer, although the bed climate both in winter and autumn was much the same.