Table 2 Sleep characteristics for the night before and the night after forest walking

Actual sleep time (min)

   42

   365.9 ± 89.4

   419.8 ± 128.7

   p = 0.02^a

Actual sleep (%)

   42

   86.9 ± 7.4

   88.0 ± 6.9

   p = 0.4^a

Sleep latency (min)

   42

   20.1 ± 32.7

   10.4 ± 9.7

   p = 0.07^a

Immobile time (min

   42

   356.3 ± 89.1

   410.2 ± 127.7

   p = 0.02^a

Sleep start time (median)

   42

   23:48

   23:46

Sleep end time (median)

   42

   6:58

   7:18

St. Mary's Hospital Sleep Questionnaire

   Self-rated depth of sleep (score)

   64

   4.7 ± 1.4

   5.1 ± 1.5

   p = 0.03^b

1: Very light

7: Deep

   Number of awakenings (times)

   66

   1.48 ± 1.24

   1.45 ± 1.34

   p = 0.7^b

0: Not at all

7: More than six times

   Sleep quality (score)

   63

   4.0 ± 1.1

   4.3 ± 1.2

   p = 0.04^b

1: Very badly

6: Very well

   Alertness on waking (score)

   62

   3.4 ± 1.2

   3.6 ± 1.3

   p = 0.054^b

1: Very drowsy

6: Very alert

   Satisfaction with sleep (score)

   63

   3.3 ± 1.0

   3.4 ± 1.1

   p = 0.3^b

1: Very unsatisfied

5: Completely satisfied

   Early morning awakening (n, % yes)

   60

   10, 16.7%

   8, 13.3%

   p = 0.7^c

1: No

2: Yes

   Difficultly falling asleep (score)

   64

   1.3 ± 0.5

   1.2 ± 0.5

   p = 0.3^b

1: None or very little 4: Extreme difficulty