Sleep in women: Normal values for sleep stages and position and the effect of age, obesity, sleep apnea, smoking, alcohol and hypertension

Abstract 

Objectives

To define normal values for total sleep time, sleep latency, sleep efficiency, sleep stages and sleeping positions in women and to investigate how sleep is affected by age, obesity, sleep apnea, smoking, alcohol dependency and hypertension.

Methods

In a population-based study, 400 Swedish women aged 20–70 years with over-sampling of snorers were investigated using overnight in-home polysomnography. All results are weighted.

Results

The mean normal total sleep time was 392min, sleep latency 22min and sleep efficiency 82%. Women spent 31min in sleep stage 1, 244min in stage 2, 41min in stage 3/4 and 76min in rapid eye movement (REM) sleep. They spent 41% of their sleep time in the supine position, 50% in the lateral position and 9% in the prone position. Multivariate analyses revealed that sleep efficiency was lower in older women and in women with hypertension. Sleep latency was short in women with severe sleep apnea and long in smokers, alcohol-dependent and hypertensive women. Sleep stage 3/4 was inversely related to age and body mass index. Less REM sleep occurred in alcohol-dependent women. Women younger than 45 years old slept a mean of 42% in the lateral position while women of 45 years and older slept 57% in the lateral position (p<0.001).

Conclusions

In this population-based study of women, we present normal values for sleep stages and sleeping position. We conclude that age, body mass index, obstructive sleep apnea, smoking, alcohol and hypertension reduce sleep quality. With age, women spend more time sleeping in the lateral position.

Keywords: Sleep apnea syndromes, Women, Polysomnography, Sleep stages, Position, Sleep quality