Sleep positions and position shifts in five age groups: an ontogenetic picture.
Level 4 - case-series / case-control
Cross-sectional observational comparative study across age cohorts
PubMed 1579788 · doi:10.1093/sleep/15.2.143
What was done
Fifty healthy participants across five age groups (3–5, 8–12, 18–24, 35–45, and 65–80 years old; 10 per group, 5 males and 5 females) were evaluated in a sleep laboratory. Participants slept for four consecutive nights (except the 3–5-year-old group, who slept for two nights) with standard polysomnography. On nights 3 and 4, sleep positions were recorded using a time-lapse Super 8 camera (one frame every 8 seconds) and categorized across four body dimensions (head, trunk, legs, arms).
What was found
Position shifts significantly decreased across advancing age cohorts, averaging 4.4, 4.7, 3.6, 2.7, and 2.1 changes per hour, respectively. Concurrently, position durations and the frequency of postural immobility periods lasting >30 minutes progressively increased. While young children distributed sleep time evenly across prone, supine, and lateral postures, aging was associated with the disappearance of prone sleeping and a progressive preference for right-side sleeping, which was most pronounced in older adults.
Why it matters
This study provides baseline normative laboratory data on how body posture dynamics and preferred sleeping orientations naturally shift across human development and aging.
Limits
The sample size was very small (n=10 per age group), limiting statistical power. The study was cross-sectional rather than longitudinal, and laboratory sleeping conditions with recording equipment may not fully represent natural home sleep behavior. The youngest group also completed fewer laboratory adaptation nights than the older cohorts.
Cited by
- partial Approximately 75% of people sleep on their sides.