shows the statistics of sleep duration each time for the
four sleep positions. The average sleep durations in the supine, left
lateral, right lateral, and prone positions were 21.5, 15.8, 13.7, and
6.8 min, respectively. The longest sleep duration occurred in the
supine position, followed by the left lateral position, the right
lateral position, and the prone position. Sleep duration in the supine
position was longer than that in the left lateral position
(t ¼ 3.301, p ¼ 0.001). The difference in sleep durations between the
left lateral and right lateral positions was not significant (t ¼ 1.506,
p ¼ 0.133). Sleep durations in the left and right lateral positions
were longer than that in the prone position (t ¼ 2.336, p ¼ 0.02).
The longest sleep duration occurred in the supine position, which
was maintained for 176 min (2.93 h), whereas the shortest duration
was in the left lateral position, which was maintained for only 2 s.