Evaluations of effects of high rebound and low rebound mattress pads on nocturanl sleep and its associated physiology

Abstract

Recently, several new materials for mattresses become introduced. Although some of these, such as low rebound (or pressure-absorbing) and high rebound mattresses have fairly different characteristics, effects of these mattresses on sleep have never evaluated. In the current study, we have evaluated effects of airweave (a high rebound [HR] mattresses using a highly breathable material) on sleep and its associated physiology and the effects were compared to those of a low rebound mattress (LR). The study was conducted in 10 healthy males, with a randomized cross over single-blind design of one night PSG (23:00 to 7:00) at the sleep laboratory with 1–2 day intervals. The mattress pads were placed on regular beds equipped in the laboratory. The mean age ( ± SD) of the 10 subjects was 26.7 ± 7.7 yrs, height, 169.6 ± 6.3 m, weight, 61.9 ± 5.2 kg, BMI, 21.2 ± 1.7, PSQID, 3.0 ± 0.7, 3% ODI, 2.3 ± 1.1, RDI, 1.8 ± 1.2. In addition to the PSG, number of roll-over during sleep, autonomic nerve activity (by monitoring EKG heart rate variability), core rectal temperature monitoring were assessed. Subjective sleep evaluations were done on the following morning, using visual analogue scales (good sleep [VAS-S] and performance [VAS-P] ) and the Stanford sleepiness scale (SSS). Performance was also evaluated with psychomotor vigilance test (PVT). The significances of the effects (between HR and LR) were evaluated with the paired- t test, except effects of rectal temperature monitoring for which a repeated measures ANOVA with a grouping factor (mattress types) was applied. Subjects slept quickly with both HR (7.1 ± 2.1 min) and LR (9.1 ± 2.6 min). Interestingly, the core body temperature was rapidly and continuously decreased with HR and reached the nadir (36.0 °C) at 2:00–3:00 while decline of the temperature with LR was modest and retained 0.4 °C higher than that with HR between 1:00 and 2:00. A significant increase in Stage 4 sleep was found with HR between 23:00 and 1:00. In addition, decrease in sympathetic nerve activity was prominent with HR between 23:00 and 1:00. There was non-significant tendency to decline in numbers of rollover and elapsed time to fall in sleep after the rollover with HR. Subjective wakefulness and performance in the next morning with HR was improved marginally significantly. Our results suggest that effective heat loss during the initial phase of sleep occurred with HR (i.e., Airweave), and this may facilitate restorative sleep. This study is supported by Airweave Inc.