Updated: June Time Spent in Sleep

Transcription

1 Updated: Time Spent in Sleep

2 Three-quarters of children ages six to twelve, and close to half of adolescents and young adults, report getting nine or more hours of sleep on school nights. Importance The role of sleep in children s development is incompletely understood. However, perceived inadequate or poor-quality sleep is associated with a number of emotional, behavioral, and health problems. 1 Remarkably, although the physiological requirement for sleep is undisputed, there is little consensus on how much sleep children actually need. 2 Normal sleep patterns vary markedly by a child s developmental stage, with six-month-old infants spending around 14 or more hours per day in sleep, preschoolers and school-age children sleeping hours daily, and adolescents typically sleeping around eight hours. 3 However, there seems to be a wide variation in individual sleep needs, even among children of the same age. 4 It takes some time to develop self-regulated patterns of night-time sleep. Newborns rarely have a consistent sleep schedule, though most infants are sleeping through the night by two or three months of age. 5 Daytime sleepiness is the subjective state associated with insufficient or disrupted sleep. 6 Adolescents, in particular, may experience sleepiness for biological reasons unrelated to time spent sleeping. Numerous studies have found that, in adolescence, the circadian rhythm (which controls waking time) shifts its phase, leading to ideal bed and waking times that are generally later than for adults or younger children. Thus, adolescents who must conform their waking times with school or work schedules may experience a sleep deficit. 7 Indeed, 20 to 60 percent of adolescents report daytime sleepiness. 8 In addition to school starting times, a number of other psychological and social factors influence children s sleep schedules. 9 For example, children s use of electronic media, particularly around bedtime, is consistently associated with negative effects on their sleep. 10 There are likely multiple mechanisms accounting for this relationship, including displacement of other activities (such as physical exercise), increased arousal, and even exposure to the blue-spectrum light typical of screens. 11 Young people s use of caffeinated beverages, as well as alcohol and a number of medications, is yet another factor that may affect the quality and duration of their sleep. 12 The available evidence suggests that poor-quality sleep is more strongly related to daytime sleepiness and diminished functioning than is sleep duration. 13 However, duration is often the focus in studies of the relation of sleep to other outcomes, such as school performance, because of its relatively uncomplicated interpretation. Despite this, even the duration of sleep is subject to measurement error, with most studies relying on self-report or on the report of parents. 14 2

3 The relationship between short sleep duration and overweight is controversial. Multiple studies, both crosssectional and longitudinal, report a significant association, especially for boys. However, there are many confounding factors that cannot be easily ruled out, and the relationship may be bi-directional. Nevertheless, the evidence is sufficient for some researchers to call for further examination of sleep modification as an obesity prevention strategy. 15 Findings linking inadequate and/or disturbed sleep with children s cognitive function (including academic difficulties), or with their emotional or behavioral problems, are also beset by issues that call into question the direction of causality. In the academic domains, effects found are generally small 16, but stronger evidence exists for the role of sleep deprivation in creating more general neuro-cognitive deficits. 17 When it comes to the regulation of emotion and behavior, it seems that these can be exacerbated by sleep difficulties, but they can also contribute to disturbed sleep. 18 Finally, there is good evidence that, sleepiness, regardless of its origins, puts children and youth at risk for unintentional injuries, and, for adolescents who are drivers, increased likelihood of motor vehicle crashes. 19 Young people, ages 16 to 29, are the group most likely to be in crashes where the cause was the driver falling asleep. Drivers getting six or seven hours of sleep a night were nearly twice as likely as those getting eight or more hours to be involved in a sleep-related crash. 20 3

4 Percent Time Spent in Sleep Trends In general, sleep duration of adolescents and young adults increased between and , while the sleeping patterns of children ages six to 12 remained relatively consistent. On weekdays, the share of adolescents and young adults who reported less than seven hours of sleep the previous night decreased over the nine years, from 20 to 16 percent among adolescents, and from 23 to 16 percent among young adults. (Figure 1) While this was the overall trend, in there was a spike in the share of young adults who got less than seven hours of sleep, to 25 percent. (Appendix 3) The proportion of adolescents who reported between seven and nine hours of sleep increased between and , from 38 to 43 percent, while the proportion of young adults who had that amount of sleep remained the same (38 percent in ). (Appendices 2 and 3) Looking at weekend days, the percentage of adolescents who reported sleeping less than nine hours peaked in , decreasing from 28 to 18 percent between and (Appendix 2) The percentage in was 25 percent. (Figure 1) The proportion of young adults reporting they slept less than nine hours decreased from 35 to 27 percent between and (Figure 1), though most of the decrease was between and (Appendix 3) Figure Hours of Sleep the Previous Night*, by Age and Day of Week, and Among children ages 6 to 12, there were no significant changes between and in time spent sleeping. (Figure 1) 10 0 less than 9 hrs less than 7 hrs less than 7 hrs less than 10 hrs less than 9 hrs less than 9 hrs Ages 6 to 12** Ages 15 to 19 Ages 20 to 24 Ages 6 to 12** Ages 15 to 19 Ages 20 to 24 weekday *Only includes days between September and May. ** Only includes children in households where there are no other children younger than 13. Source: Child Trends analysis of the American Time Use Survey. Differences by Age In , adolescents and young adults were equally likely (14 and 16 percent, respectively) to report sleeping less than seven hours on a weekday, and weekend also equally likely (43 and 38 percent, respectively) to report between seven and nine hours of sleep. (Appendices 2 and 3) However, adolescents were less likely than young adults to sleep less than nine hours on weekends: 18 compared with 27 percent, respectively. (Figure 1) 4

5 Percent Time Spent in Sleep Children ages 6 to 12 slept more than their older counterparts. On weekdays, 70 percent slept nine hours or more, compared with 43 percent of adolescents and 46 percent of young adults. They also slept more on weekends. Seventy-two percent of children slept ten hours or more, compared with 29 percent of adolescents and 48 percent of young adults. (Figure 2) Figure Hours of Sleep the Previous Night*, by Age and Day of Week, they reported getting on weekdays or weekends. (Appendix 2) 46 9 hours or more 10 hours or more weekday *Only includes days between September and May. ** Only includes children in households where there are no other children younger than 13. Source: Child Trends analysis of the American Time Use Survey. Ages 6 to 12** Ages 15 to 19 Ages 20 to weekend 48 Differences by School Enrollment and Employment Status There was no difference in between adolescents who were both in school and employed, and those who were in school only, in the amount of sleep On weekdays in , young adults who were both employed and in school were less likely to report getting between seven and nine hours of sleep on the previous night than those who were employed only (11 compared with 52 percent). The two groups were equally likely to get less than seven or more than nine hours of sleep on weekdays, and to get nine hours of sleep or more on weekends. (Appendix 3) State and Local Estimates Parents estimates of the number of nights on which their child got enough sleep in the past week, by state, are available from the National Survey of Children s Health, through the Data Resource Center for Child and Adolescent Health, at International Estimates None available. 5

6 National Goals Through its Healthy People 2020 initiative, the federal government has set a goal to increase the proportion of students in grades 9 through 12 who get more than eight hours of sleep on an average school night. They have also set a goal to increase the proportion of adults ages 18 to 21 who got more eight or more hours of sleep in a 24-hour period. More information is available here: (Goals SH-3 and SH-4) What Works to Make Progress on This Indicator Parental rules and routines around children s bedtimes and use of electronic media prior to bedtime, appropriate to the child s age, have been associated with reduced behavioral problems 21, and are recommended to improve sleep quality. 22 Later school start-times for adolescents is a promising strategy that has gained the endorsement of a number of scientists. 23 Preliminary evidence shows that delayed starting times are associated with improved attendance, discipline, alertness, mood, and health. 24 Also, see Child Trends LINKS database ( Lifecourse Interventions to Nurture Kids Successfully ), for reviews of many rigorously evaluated programs, including the following which have been shown to be effective in improving sleep quality: Busselton Health Study: Mindfulness-Based Stress Reduction (MBSR): Related Indicators Youth Employment: Unintentional Injuries: Distracted Driving: 6

7 Regular Bedtime and Mealtime (archived): 7

8 Definition Non-institutional, civilian adolescents and young adults, ages 15 to 24, were interviewed about how they spent their time in the previous day. The previous day included all of the hours between 4 am the previous day and 4 am on the current day. Half were asked about a Saturday or a Sunday. Respondents reported when they went to bed and when they woke up, including naps, but excluding significant time spent lying in bed not sleeping (sleeplessness). Those who reported sleeping for up to 419 minutes were classified as sleeping less than seven hours. Those who reported sleeping between 420 and 539 minutes were classified as sleeping between seven and nine hours. Those who reported sleeping at least 540 minutes were classified as sleeping nine or more hours. For children ages six to twelve, the data are based on adult report of when the child woke up and when they went to bed. Children in households that had more than one child younger than 13 were excluded, due to data constraints. Time spent sleeping was calculated as the number of hours between midnight and when the child woke up, and the number of hours between the time the child went to bed and the next midnight. Naps were not included in the sleeping estimate, and children who went to bed between midnight and noon were counted as having gone to bed at midnight. For these estimates, only respondents who replied to the survey between September and May were included. A weekend was defined as either a Saturday or a Sunday, or one of the following holidays: New Year's Day, Easter, Memorial Day, the Fourth of July, Labor Day, Thanksgiving Day, or Christmas Day. Data Source Child Trends analysis of the American Time Use Survey. Raw Data Source American Time Use Survey 8

9 Appendix 1 - Among Children Ages Six to 12, Percentage Getting Different Amounts of Sleep on the Previous Night, by Parents Report: Weekdays: Less than 9 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Weekdays: 9 to less than 10 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Weekdays: 10 hours or more Male Female White, non-hispanic Black, non-hispanic Hispanic

10 (ages 6-12) Weekends: Less than 10 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Weekends: 10 hours or more Male Female White, non-hispanic Black, non-hispanic Hispanic fewer than 20 cases. 1 Data shown are two-year rolling averages, in order to ensure sufficient sample sizes. Source: Child Trends analysis of the American Time Use Survey. 10

11 Appendix 2 - Among Adolescents Ages 15 to 19, Percentage Who Report Getting Different Amounts of Sleep on the Previous Night, Weekdays: Less than 7 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school Weekdays: 7 to less than 9 hours Male Female White, non-hispanic Black, non-hispanic Hispanic

12 (ages 15-19) Just in school Just employed Employed and in school school Weekdays: 9 hours or more Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school

13 (ages 15-19) Weekends: Less than 9 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school Weekends: 9 hours or more Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school - fewer than 20 cases. 1 Data shown are two-year rolling averages, in order to ensure sufficient sample sizes. Source: Child Trends analysis of the American Time Use Survey

14 Time Spent Sleeping Appendix 3 - Among Young Adults Ages 20 to 24, Percentage Who Report Getting Different Amounts of Sleep on the Previous Night, Weekdays: Less than 7 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school Weekdays: 7 to less than 9 hours Male Female White, non-hispanic Black, non-hispanic Hispanic

15 Time Spent Sleeping (ages 20-24) Just in school Just employed Employed and in school school Weekdays: 9 hours or more Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school

16 Time Spent Sleeping (ages 20-24) Weekends: Less than 9 hours Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school Weekends: 9 hours or more Male Female White, non-hispanic Black, non-hispanic Hispanic Just in school Just employed Employed and in school school - fewer than 20 cases. 1 Data shown are two-year rolling averages, in order to ensure sufficient sample sizes. Source: Child Trends analysis of the American Time Use Survey

17 Endnotes 1 Millman, R. P., Working Group on Sleepiness in Adolescents/Young Adults, and AAP Committee on Adolescence. (2005). Excessive sleepiness in adolescents and young adults: Causes, consequences, and treatment strategies. Pediatrics, 115(6), Gregory, A. M., and Sadeh, A. (2012). Sleep, emotional and behavioral difficulties in children and adolescents. Sleep Medicine Reviews, 16, Dewald, J. F., Meijer, A. M., Oort, F. J., Kerkhof, G. A., and Bögels, S. M. The influence of sleep quality, sleep duration and sleepiness on school performance in children and adolescents: A meta-analytic review. Sleep Medicine Reviews, 14, Beebe, D. W. (2011). Cognitive, behavioral, and functional consequences of inadequate sleep in children and adolescents. Pediatric Clinics of North America, 58(3), National Sleep Foundation. How much sleep do we really need? Retrieved March 31, 2014 from Matricciani, L. A., Olds, T. S., Blunden, S., Rigney, G., and Williams, M. T. (2012). Never enough sleep: A brief history of sleep recommendations for children. Pediatrics, 129(3), Iglowstein, I., Jenni, O. G., Molinari, L., and Largo, R. H. (2003). Sleep duration from infancy to adolescence: Reference values and generational trends. Pediatrics, 111(2), Galland, B. C., Taylor, H. J., Elden, D. E., and Herbison, P. (2012)Normal sleep patterns in infants and children: A systematic review of observational studies. Sleep Medicine Reviews, 16(3), Mercer, P. W., Merritt, S. L., and Cowell, J. M. (1998). Differences in reported sleep need among adolescents. Journal of Adolescent Health, 23, ; Dewald et al., op. cit; Spruyt et al, op. cit. 5 Henderson, J. M. T., France, K. G., Owens, J. L., and Blampied, N. M. Sleeping through the night: The consolidation of self-regulated sleep across the first year of life. Pediatrics, 126(5), e Dewald et al. Op. cit. 7 Kirby, M., Maggi, S., and D Angiulli, A. (2011). School start times and the sleep-wake cycle of adolescents: A review and critical evaluation of available evidence. Educational Researcher, 40(2), Beebe, op. cit. 8 Dewald et al., op. cit.; Mercer et al., op. cit. 17

18 9 Carskadon, M. A. (2011). Sleep in adolescents: The perfect storm. Pediatric Clinics of North America, 58(3), Cain, N. and Gradisar, M. Electronic media use and sleep in school-aged children and adolescents: A review. Sleep Medicine, 11, Marinelli, M., Sunyer, J., Alvarez-Pedreroi, M., Iňeguez, C., Torrent, M., Vioque, J., Turner, M. C., and Julvez, J. 11 Cain, N. and Gradisar, M. Electronic media use and sleep in school-aged children and adolescents: A review. Sleep Medicine, 11, Carskadon, M. A. (2011). Sleep in adolescents: The perfect storm. Pediatric Clinics of North America, 58(3), Millman et al., op. cit. 13 Dewald et al., op. cit. 14 Beebe, op. cit. 15 Chen, X., Beydoun, M. A., and Wang, Y. (2007). Is sleep duration associated with child obesity? A systematic review and meta-analysis. Obesity,16(2), Spruyt, K., Molfese, D. L, and Gozal, D. (2011). Sleep duration, sleep regularity, body weight, and metabolic homeostasis in school-aged children. Pediatrics, 127(2), e345-e352. Carskadon, op. cit. 16 Dewald et al. Op. cit. 17 Beebe, op. cit. 18 Gregory & Saleh, op. cit. 19 Beebe, op. cit.; Millman et al., op. cit. 20 Millman et al., op. cit. 21 Kelly, Y., Kelly, J., and Sacker, A. (2013). Changes in bedtime schedules and behavioral difficulties in 7-year-old children. Pediatrics, 132(5), e1184-e Carskadon, op. cit; Gregory and Sadeh, op. cit.; National Sleep Foundation. (2014). Sleep in America poll: Sleep in the modern family. Summary of findings. Retrieved from 23 Carskadon, op. cit.; Dewald et al., op. cit.; Kirby et al., op. cit. 24 Kirby et al., op. cit. 18