Health Reports
Meeting the Canadian 24-Hour Movement Guidelines for Children and Youth

by Karen C. Roberts, Xiaoquan Yao, Valerie Carson, Jean-Philippe Chaput, Ian Janssen and Mark S. Tremblay

Release date: October 18, 2017

For children and youth, regular moderate-to-vigorous physical activity (MVPA) has positive impacts on physical and mental health in the short- and long-term.Note 1Note 2Note 3 But although MVPA tends to be the focus of attention, all movement behaviours are related to health.Note 4Note 5Note 6Note 7 Notably, independent benefits of limiting sedentary time (specifically, screen time) for adiposity, fitness, self-esteem, academic performance, and pro-social behaviour have been documented.Note 8Note 9Note 10 Evidence also suggests that inadequate sleep is associated with weight gain, depression, and poor academic performance.Note 11Note 12Note 13

ResearchNote 1Note 3Note 4 has highlighted the importance of an integrated approach that considers all behaviours across the movement continuum.Note 9Note 14Note 15 The Canadian 24-Hour Movement Guidelines for Children and Youth: An Integration of Physical Activity, Sedentary Behaviour, and SleepNote 14 were released in June 2016. These Guidelines provide general recommendations for children and youth aged 5 to 17 related to MVPA, light physical activity, sedentary behaviour and sleep, and specific recommendations on the time that should be spent in MVPA, recreational screen time, and sleep during a typical 24-hour day.

This article uses combined data from two cycles of the Canadian Health Measures Survey to examine the extent to which children and youth meet the recommendations in the Guidelines.

Methods

Data source

The Canadian Health Measures Survey (CHMS) collects data from a nationally representative sample of the population aged 3 to 79 living in private households.Note 16 The survey excludes residents of Indian reserves, institutions and remote regions and full-time members of the Canadian Forces, who together account for about 4% of the target population.

Ethics approval for the CHMS was obtained from the Health Canada Research Ethics Board. For children aged 5 to 13, a parent or legal guardian gave written informed consent, and assent was obtained from the child. Youth aged 14 or older provided independent written informed consent. Participation was voluntary; respondents could withdraw at any point.

This study pertains to 5- to 17-year-olds. To increase sample size and the precision of estimates, data from CHMS cycles 2 (2009-to-2011) and 3 (2012-to-2013) were combined.Note 17

Respondents answered an interviewer-administered questionnaire at home and visited a mobile examination centre (MEC) where physical measures were taken. For children aged 5 to 11, the household questionnaire was answered by a parent/guardian.

After the MEC visit, ambulatory respondents were asked to wear an Actical accelerometer (Phillips – Respironics, Oregon, USA) over their right hip on an elasticized belt during waking hours for 7 consecutive days. The accelerometers were initialized to start collecting data at midnight following the MEC visit. Data were collected in 60-second epochs for all respondents in cycle 2, and for those aged 6 or older in cycle 3. In cycle 3, data for 5-year-olds were collected in 15-second epochs to align with current research.Note 18 When cycle 2 and cycle 3 data were combined, correction equationsNote 19 were applied to adjust for the difference in epoch length for 5-year-olds. The accelerometer cut-points used in the CHMS to define MVPA for 5-year-olds (288 counts per 15-seconds) and for 6- to 17-year-olds (1,500 counts per minute) were obtained from energy expenditure calibration studies.Note 20Note 21 Descriptions of the survey design, sample, interview procedures, MEC protocols, and activity monitor (accelerometer) are published elsewhere.Note 16Note 22Note 23

A total of 4,123 respondents aged 5 to 17 completed the household questionnaire and visited the MEC; 3,119 (75.6%) of them returned accelerometers with a minimum of 4 valid days of data.Note 22 Of these respondents, 8 were excluded for incomplete screen-time information. The final sample (3,111) was evenly split between boys (1,553) and girls (1,541). Because of oversampling of younger children, 5- to 11-year-olds (1,985) outnumbered 12- to 17-year-olds (1,126); however, the weighted percentages of each age group were the same (49.9% and 50.1%).

A valid day was 5 or more hours of accelerometer wear time during waking hours for 5-year-olds, and 10 or more hours for 6- to 17-year-olds.Note 18 Wear time was calculated by subtracting non-wear time (periods of at least 60 consecutive minutes of zero counts, allowing up to 2 minutes of counts between zero and 100) from 24 hours. Mean wear time for valid days was 12.3 hours for 5-year-olds, and 13.6 hours for 6- to 17-year-olds.

The overall response rate for the household questionnaire, MEC visit, and return of an accelerometer with sufficient valid days was 40.7% for cycles 2 and 3 combined. To correct for the potential bias of the low response rate to the accelerometer portion of the survey, and for bias introduced by differences between respondents with and without valid data, Statistics Canada generated separate survey weights for the accelerometer subsample.Note 17 Details about combining CHMS cycles and collecting and processing the accelerometer data are published elsewhere.Note 17Note 18Note 22

Respondent age was determined at the time of the household interview. For consistency with previous physical activity and sedentary behaviour guidelinesNote 24Note 25 and previous CHMS analyses,Note 26 respondents were grouped into children (ages 5 to 11) and youth (ages 12 to 17).

Meeting the 24-Hour Guidelines

The Guidelines provide general recommendations related to MVPA, light physical activity, sedentary behaviour, and sleep for a 24-hour day, and specific daily time recommendations for MVPA (at least 60 minutes), recreational screen-time (no more than 2 hours), and uninterrupted sleep (9 to 11 hours at ages 5 to 13; 8 to 10 hours at ages 14 to 17). Individuals were considered to have met the Guidelines if, on average, during a week they met all three specific time recommendations.Note 14

Physical activity

Physical activity information was derived from the accelerometer data. The number of minutes of MVPA on each valid day was summed, and daily totals were averaged.

Sleep

Sleep duration was parent-reported (ages 5 to 11) or self-reported (ages 12 to 17). Average daily sleep time was determined from the question: “How many hours do you usually spend sleeping in a 24-hour period, excluding time spent resting?” Answers were rounded to the closest half hour by the interviewer. Respondents were categorized as meeting the recommendations if the amount of time fell within the appropriate range for the age group.

Screen time

Screen time was estimated separately for children aged 5 to 11 and youth aged 12 to 17. For children, the parent/guardian was asked, on average, how many hours per day the child spends: 1) watching TV or videos or playing video games; and 2) on a computer. The response categories differed between cycle 2 (none, less than 1, 1 to 2, 3 to 4, 5 to 6, 7 or more) and cycle 3 (none, less than 1, 1 to less than 3, 3 to less than 5, 5 to less than 7, 7 or more). For cycle 2, average daily screen time was derived using the mid-point of the response category (0, 0.5, 1.5, 3.5, 5.5, 7). To maintain consistency, the same values were assigned to each of the respective categories for cycle 3. Responses to the two questions were summed to determine average daily screen time.

Youth aged 12 to 17 were asked how much time they spent in a typical week over the past three months: 1) on a computer; 2) playing video games; and 3) watching television, DVDs or videos. Responses were summed across all questions, and average daily screen time was calculated. The video game questions differed between cycles. Cycle 2 asked a single question, whereas cycle 3 asked about active video games separately from other video games. Active video game time was excluded from the screen-time estimate for cycle 3 respondents. Respondents were categorized as meeting the screen-time recommendation if they reported no more than 2 hours per day.

Statistical analyses

All analyses were performed with SAS Enterprise Guide version 5.1 (SAS Institute, Cary, NC). Accelerometer survey weights for the combined cycles 2 and 3 were used to ensure that results were representative of the Canadian population aged 5 to 17.

Descriptive statistics were used to examine average daily MVPA, screen time and sleep duration, and the percentage of respondents meeting the recommendations for each movement behaviour separately and for all possible groupings.

Findings are presented for the entire sample and by age group and sex. A surveyreg procedure was used to test the significance of differences in average daily behaviour times between groups. Rao-Scott chi-square test was used to test for differences between groups in the percentage of respondents meeting each recommendation and combination of recommendations. Statistical significance was set at a p value of 0.05.

The 95% confidence intervals and coefficients of variation were derived using the bootstrap re-sampling method to account for the complex sampling design of the CHMS.Note 18Note 27

Results

Compared with 12- to 17-year-olds, children aged 5 to 11 averaged significantly more MVPA (61.3 versus 46.3 minutes per day), less screen time (2.3 versus 3.8 hours), and more sleep (9.6 versus 8.3 hours) (Table 1). Boys had more MVPA (60.1 versus 47.1 minutes) and screen time (3.3 versus 2.8 hours) than did girls. Average sleep duration did not differ between the sexes in either age group.

About a third (36.0%) of children and youth met the specific time MVPA recommendation; almost half (49.3%) met the screen-time recommendation; and three quarters (75.3%) met the sleep recommendation (Table 2). Children aged 5 to 11 were more likely than 12- to 17-year-olds to meet the recommendations for MVPA (47.6% versus 24.4%), screen time (70.6% versus 28.1%), and sleep (82.6% versus 68.1%).

The percentage of boys meeting the MVPA recommendation was almost double that of girls: 46.8% versus 24.6%. Differences between boys and girls were significant at ages 5 to 11 (59.6% versus 35.0%) and at ages 12 to 17 (34.1% versus 14.1%) for MVPA. Among youth (but not children), the percentage of girls meeting the screen-time recommendation was higher than the percentage of boys: 32.8% versus 23.6%. Differences in the percentages meeting the sleep duration recommendation were not significant.

Overall, 17.5% of children and youth met all three recommendations (Table 3). The percentage was significantly higher at ages 5 to 11 (29.6%) than at ages 12 to 17 (5.5%). This difference between age groups was apparent among boys (37.3% versus 8.7%) and among girls (21.6% versus 2.0%). More than one-fifth (22.9%) of boys met all three recommendations, compared with 11.8% of girls.

More than one in ten (10.7%) children and youth did not meet any of the recommendations; just over half (53.8%) met at least two. Almost half of 5- to 11-year-olds (45.8%) met two recommendations; the figure was lower (26.8%) at ages 12 to 17.

Discussion

The 24-Hour Guidelines recommendation for MVPA is identical to that of the previous guidelines,Note 24 the methodology for determining adherence differs.Note 14 A threshold of 60 minutes of MVPA on at least 6 days of the week has historically been used.Note 26 By contrast, the Guidelines use average daily MVPA, which allows for normal day-to-day variability and ensures consistency in the approach for each movement behaviour.Note 2Note 14 Consequently, the percentage of children and youth who were reported to meet the recommendation in this study (36.0%) is not directly comparable to previous estimates based on CHMS data (9.3%).Note 28 However, minutes of MVPA per day and trends by age and sex are comparable with earlier reports.Note 29

Previously, Canada did not have guidelines for sleep; instead, an expert consensus statementNote 30 was used for surveillance reporting.Note 28 The thresholds differed slightly from those of the Guidelines for 5-year-olds (10 to 13 hours instead of 9 to 11 hours per day), but the percentages of children and youth obtaining adequate sleep were similar: 75.3% in the present study, compared with 74.6% based on the 2012-to-2013 CHMS.Note 28

The screen-time recommendation in the Guidelines is identical to that of the previous Canadian guidelines.Note 25 Results of this study align with those previously reported.Note 28

Strengths and limitations

Despite limitations in accelerometers’ ability to capture MVPA during some activities (such as cycling and upper body exercises) and for activities during which the device is not worn (such as swimming), the data are considered to be more robust than self-reports.

Self- (or parent-) reported data were used for screen time and sleep. Although subject to social desirability and recall bias, self-reported screen time has acceptable reliability and validity in children.Note 31

Differences between cycles 2 and 3 in the response option categories for the screen-time questions for 6- to 11-year-olds introduced some imprecision in the estimation of adherence to the recommendations. Nonetheless, the distributions of responses in each category in the two cycles were similar, so it is unlikely that prevalence changed dramatically between cycles. Therefore, use of the same values for similar response categories (in this case, mid-points from cycle 2) was considered appropriate.

Inclusion of a question about active video games in cycle 3, but not cycle 2, may have affected comparability between cycles. Excluding time spent in active video games, even if possible only in cycle 3, was justifiable, given evidence that active video games are non-sedentary.Note 32

Objective measures of sleep and/or additional questions about sleep quality might better assess whether sleep is “uninterrupted.” However neither was available on the CHMS at the time of this analysis.

Conclusion

Rates of adherence to the 24-Hour Guidelines recommendations are useful for the development of public health policies, programs, and interventions. The percentages of Canadian children and youth meeting the Guidelines were low; fewer than 1 child in 3, and fewer than 1 youth in 20, met all three of the recommendations that have established cut-points.

References
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