Table 3 Polysomnogram data for total nights’ sleep (excluding the last 20 min before awakening) and the last 20 min of sleep

 Time in bed (min)

382.0

(8.0)

382.0

(8.0)

–

–

 Total sleep time (min)

371.9

(7.8)

376.8

(7.9)

1.82

n.s.

 Sleep efficiency (%)

97.4

(0.7)

98.6

(0.2)

1.85

n.s.

 Wake after sleep onset (min)

2.5

(0.6)

1.6

(0.4)

1.85

n.s.

 Stage N1 (min)

43.2

(9.8)

21.5

(6.3)

1.12

n.s.

 Stage N2 (min)

192.5

(19.1)

208.9

(3.3)

0.98

n.s.

 Stage N3 (min)

49.9

(8.0)

44.2

(6.2)

0.57

n.s.

 Stage REM (min)

73.6

(8.0)

90.0

(2.2)

1.61

n.s.

 Movement time (min)

12.6

(1.5)

12.2

(1.1)

0.31

n.s.

 Time in bed (min)

20.0

–

20.0

–

–

–

 Total sleep time (min)

15.7

(0.9)

19.7

(0.2)

4.35

< 0.01

 Sleep efficiency (%)

78.7

(4.4)

98.5

(1.1)

4.62

< 0.01

 Wake after sleep onset (min)

3.9

(1.3)

0.2

(0.2)

3.28

< 0.01

 Stage N1 (min)

6.1

(1.0)

1.5

(0.7)

3.58

< 0.01

 Stage N2 (min)

8.0

(1.7)

11.4

(2.7)

1.08

n.s.

 Stage N3 (min)

–

–

–

–

–

–

 Stage REM (min)

1.6

(1.0)

6.3

(2.6)

1.81

n.s.

 Movement time (min)

0.4

(0.2)

0.5

(0.2)

0.45

n.s.