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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 ± 1.25.7 ± 1.35.0 ± 0.56.8 ± 0.94.3 ± 1.0
Sleep duration on weekends (h)8.0 ± 1.57.9 ± 1.68.5 ± 1.67.4 ± 1.18.6 ± 1.8
Bedtime on weekdays (h:m)0:44 ± 1:070:57 ± 1:120:10 ± 0:221:34 ± 0:382:20 ± 1:01
Bedtime on weekends (h:m)0:55 ± 1:241:06 ± 1:280:39 ± 2:111:51 ± 0:462:31 ± 1:20
Wake-up time on weekdays (h:m)6:48 ± 1:036:44 ± 1:035:42 ± 0:428:31 ± 0:506:46 ± 0:54
Wake-up time on weekends (h:m)9:02 ± 1:489:11 ± 1:579:21 ± 1:419:32 ± 0:5311:20 ± 1:43
Extension of sleep duration on weekends (h)2.1 ± 1.72.3 ± 2.03.5 ± 1.50.7 ± 0.64.4 ± 1.8
MEQ score48.6 ± 7.547.9 ± 7.751.0 ± 6.237.1 ± 2.836.9 ± 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 score6.2 ± 3.79.7 ± 3.17.5 ± 3.76.3 ± 3.78.4 ± 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 score11.4 ± 4.612.4 ± 4.414.6 ± 2.911.0 ± 4.014.7 ± 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