Table 3 Comparison of sleep timing and duration among the JFCT members

Nights before days off

Bedtime (A)

23:28 ± 1:03

23:20 ± 1:03

0:28 ± 0:45 ^a

23:28 ± 0:59

4.268

0.01

Wake time (B)

7:15 ± 0:45

7:03 ± 1:09

7:40 ± 0:43

7:11 ± 0:51

1.257

0.301

Length from A to B

7:47 ± 0:25

7:43 ± 0:50

7:12 ± 0:34

7:44 ± 1:04

1.623

0.198

Between consecutive day shifts

Bedtime (A)

22:56 ± 0:33

23:09 ± 0:46

23:43 ± 0:56

22:58 ± 0:56

2.54

0.068

Wake time (B)

5:34 ± 0:40

6:09 ± 0:28

6:13 ± 0:36

5:53 ± 0:41

2.537

0.069

Length from A to B

6:38 ± 0:21

7:00 ± 0:42

6:30 ± 0:54

6:55 ± 0:57

1.182

0.327

Between consecutive evening shifts

Bedtime (A)

3:25 ± 1:24

3:10 ± 0:51

3:21 ± 0:49

0.23

0.796

Wake time (B)

9:30 ± 2:06

9:50 ± 1:44

9:28 ± 1:29

0.19

0.828

Length from A to B

6:05 ± 1:07

6:39 ± 1:16

6:06 ± 0:59

1.233

0.302

Total time allocated for sleep

6:18 ± 0:45

6:58 ± 0:58

6:28 ± 0:36

2.754

0.076

Between consecutive night shifts

Bedtime (A)

12:30 ± 1:54

12:17 ± 2:31

12:12 ± 2:25

0.054

0.948

Wake time (B)

18:00 ± 2:40

17:36 ± 3:20

17:54 ± 3:52

0.054

0.947

Length from A to B

5:30 ± 1:19

5:19 ± 1:40

5:42 ± 1:59

0.19

0.828

Total time allocated for sleep

6:25 ± 1:25

6:42 ± 1:44

6:42 ± 1:15

0.152

0.860

Percentages of evening nappers (napping after 7 p.m.)

45.5 % (5)

43.8 % (7)

28.6 % (4)

4.901

0.086