Effects of two kinds of pillow on thermoregulatory responses during night sleep

We compared thermoregulatory responses during night sleep between two kinds of pillow. One has special cool medium consisting of sodium sulfate and ceramic fiber (pillow A) and the other polyester padding (pillow B). The subjects wore 100% cotton thin pajamas with short sleeves and three-quarters trousers for summer use. They lay and slept in bed with cotton sleeping mat and cotton quilt between 10:30 p.m. and 6:30 a.m. in a bed room with an ambient temperature (Ta) of 27 +/- 1 degrees C and a relative humidity of 55 +/- 5%, using either of the pillow A or pillow B. When they awoke, the subjects filled out a questionnaire on how well they slept during sleep. Main results were: 1) Rectal and forehead skin temperatures and heart rate were kept significantly lower in the pillow A during the latter half of the night sleep. 2) Palm and thigh skin temperatures were significantly higher mostly in the pillow A. 3) All the subjects regarded the pillow A better for deeper sleep. It was concluded that slight cooling of the head due to the pillow A during night sleep seemed to be of significance for deep sleep.