Outline of the Fourth Longitudinal Survey of Newborns in the 21st Century

3.Situations of Children

(1)

Bedtime and Wakeup Time

25.9% of all children surveyed goes to bed "in the 9:00 pm range" and wake up "in the 7:00 am range".

The most common sleeping hours was "in the range of 10 hours".

As for the combination of bedtime and wakeup time, the largest proportion of the subjects (25.9%) goes to bed "in the 9:00 pm range" and wake up "in the 7:00 am range". The most common sleeping hours, calculated from the combination of bedtime and wakeup time, was "in the range of 10 hours" with the proportion of 41.9% (Table 8 & Figure 5).

Table 8 Bedtimes and wakeup times of children

(Unit: %)

		Bedtime
		Total	Before 8 pm	8:00 - 8:59 pm	9:00 - 9:59 pm	10:00 - 10:59 pm	After 11:00 pm	Irregular
Wakeup time	Total	100.0	2.1	13.8	43.9	29.6	7.4	2.9
	Before 6:00 am	1.6	0.3	0.6	0.6	0.1	0.0	0.0
	6:00 - 6:59 am	21.8	1.1	6.0	11.7	2.8	0.1	0.1
	7:00 - 7:59 am	52.1	0.6	6.7	25.9	16.3	1.7	0.8
	8:00 - 8:59 am	18.3	0.0	0.6	5.4	8.9	2.8	0.6
	After 9:00 am	4.3	0.0	0.0	0.3	1.3	2.4	0.2
	Irregular	1.8	-	0.0	0.1	0.3	0.3	1.1

Notes:	1)	The figures are based on the total responses to the 4th survey (total replies: 41,557).
Notes:	2)	The total includes the number of samples with "unknown" for each item.

Figure 5 Sleeping hours of children

Notes:	1)	The figures are based on the total responses to the 4th survey (total replies: 41,557).
Notes:	2)	The sleeping hours are calculated from the combination of bedtime and wakeup time.

Both bedtimes and wakeup times became earlier than in the previous survey.

Comparing the bedtimes and wakeup times between the 3rd survey (30 months old) and the 4th survey (42 months old), the proportion of children going to bed "after 10:00 pm" decreased from 43.8% to 37.0%, and the rate of children waking up "before 7:00 am" increased from 19.5% to 23.4%, resulting in more early hours as a whole (Figure 6).

Figure 6 Changes in bedtimes and wakeup times of children

Note:

The figures are based on the total responses to the 3rd and 4th surveys (total replies: 40,616).

The rate of children going to bed after 10:00 pm rises as their mothers work longer.

Looking at the bedtimes of children in relation with the working hours per week of their mothers, the rate of children going to bed after 10:00 pm rises as their mothers work longer, with the percentages marking respectively at 35.5% with mothers working less than 20 hours, 41.2% with mothers working less than 40 hours, 43.9% with mothers working less than 60 hours, and at 49.3% with mothers working for 60 hours or more per week (Table 9).

Table 9 Bedtimes of children in relation
with the working hours of their mothers and fathers

(Unit: %)

	Total		Before 9:00 pm	9:00 - 9:59 pm	10:00 - 10:59 pm	After 11:00 pm	Irregular	(Previously reported) After 10:00 total
Mother's working hours per week
Total	(100.0)	100.0	15.9	43.9	29.6	7.4	2.9	37.0
Employed	(42.2)	100.0	10.5	46.5	34.3	6.4	2.1	40.7
Working hours	(39.2)	100.0	10.6	46.3	34.4	6.3	2.1	40.7
Less than 20 hours	(9.8)	100.0	16.4	45.5	29.5	6.0	2.5	35.5
Less than 40 hours	(17.3)	100.0	10.1	46.5	35.1	6.1	2.0	41.2
Less than 60 hours	(11.3)	100.0	6.6	47.4	37.3	6.6	1.9	43.9
60 hours or more	(0.8)	100.0	8.0	37.4	37.7	11.6	4.7	49.3
Unemployed	(56.7)	100.0	19.9	42.0	26.1	8.2	3.5	34.3
Father's working hours per week
Total	(100.0)	100.0	16.1	44.0	29.4	7.4	2.9	36.8
Employed	(98.0)	100.0	16.2	44.0	29.4	7.3	2.8	36.8
Working hours	(93.8)	100.0	16.0	44.0	29.5	7.4	2.8	36.9
Less than 20 hours	(1.7)	100.0	15.2	41.1	28.5	9.5	5.4	38.0
Less than 40 hours	(7.5)	100.0	13.9	45.2	31.6	6.4	2.8	38.0
Less than 60 hours	(57.9)	100.0	15.1	44.6	30.5	7.0	2.5	37.5
60 hours or more	(26.7)	100.0	18.7	42.6	26.8	8.4	3.3	35.2
Unemployed	(1.1)	100.0	11.4	39.1	32.0	10.9	6.6	42.9

Notes:	1)	The figures are based on the responses to the 4th survey, of which children living with their mothers (total number: 41,393) or fathers (total number: 39,592).
Notes:	2)	The total includes the number of samples with "unknown" for each item. The "employed" includes "no working hours" and "working hours unknown."

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