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Table 2 Sleep-wake pattern in the groups with sleep problems

From: Impact of sleep problems on daytime function in school life: a cross-sectional study involving Japanese university students

  Total
(n = 1034)
Insomnia (n = 257) BIISS
(n = 28)
DSWP
(n = 20)
BIISS + DSWP
(n = 46)
Sleep duration on weekdays (h) 5.9 ± 1.2 5.7 ± 1.3 5.0 ± 0.5 6.8 ± 0.9 4.3 ± 1.0
Sleep duration on weekends (h) 8.0 ± 1.5 7.9 ± 1.6 8.5 ± 1.6 7.4 ± 1.1 8.6 ± 1.8
Bedtime on weekdays (h:m) 0:44 ± 1:07 0:57 ± 1:12 0:10 ± 0:22 1:34 ± 0:38 2:20 ± 1:01
Bedtime on weekends (h:m) 0:55 ± 1:24 1:06 ± 1:28 0:39 ± 2:11 1:51 ± 0:46 2:31 ± 1:20
Wake-up time on weekdays (h:m) 6:48 ± 1:03 6:44 ± 1:03 5:42 ± 0:42 8:31 ± 0:50 6:46 ± 0:54
Wake-up time on weekends (h:m) 9:02 ± 1:48 9:11 ± 1:57 9:21 ± 1:41 9:32 ± 0:53 11:20 ± 1:43
Extension of sleep duration on weekends (h) 2.1 ± 1.7 2.3 ± 2.0 3.5 ± 1.5 0.7 ± 0.6 4.4 ± 1.8
MEQ score 48.6 ± 7.5 47.9 ± 7.7 51.0 ± 6.2 37.1 ± 2.8 36.9 ± 4.3
Chronotypea
 Morning-type n (%) 95 (9.2) 22 (8.6) 4 (14.3) 0 (0) 0 (0)
 Neutral-type n (%) 693 (67.0) 165 (64.2) 24 (85.7) 0 (0) 0 (0)
 Evening-type n (%) 168 (16.2) 47 (18.3) 0 (0) 20 (100) 46 (100)
 N/A n (%) 78 (7.5) 23 (8.9)
Athenes Insomnia Scale score 6.2 ± 3.7 9.7 ± 3.1 7.5 ± 3.7 6.3 ± 3.7 8.4 ± 3.6
Athenes Insomnia Scale score ≥ 6 n (%) 544 (52.6) 257 (100) 19 (67.9) 11 (55.0) 36 (78.3)
Insomniab n (%) 257 (24.9) 257 (100) 8 (28.6) 4 (20.0) 20 (43.5)
Epworth Sleepiness Scale score 11.4 ± 4.6 12.4 ± 4.4 14.6 ± 2.9 11.0 ± 4.0 14.7 ± 3.2
Epworth Sleepiness Scale score ≥ 11 n (%) 580 (56.1) 167 (65.0) 28 (100) 12 (60.0) 46 (100)
Sleep duration on weekdays < 6 h n (%) 395 (38.2) 119 (46.3) 28 (100) 0 (0) 46 (100)
Bed time after 1:00 am on weekdays n (%) 534 (51.6) 153 (59.5) 0 (0) 20 (100) 46 (100)
  1. Values are expressed as mean ± standard deviation for continuous variables
  2. N/A Unanswered
  3. MEQ Morningness-Eveningness questionnarie
  4. aChronotype: total score for the Morningness-Eveningness questionnaire score below 42 is defined as evening-type, 42–58 as neutral-type, and above 58 as morning-type
  5. bInsomnia: Atenes Insomnia Scale score ≥ 6 and one or more of “Difficulty in initiationg sleep”, “Difficulty in maintaining sleep”, and “Early morning awakening”
  6. BIISS Behaviorally induced insufficient sleep syndrome, DSWP Delayed sleep-wake phase