Is adherence to the 24-hour movement guidelines associated with a reduced risk of adiposity among children and adolescents?

BACKGROUND: Little is known about the combined effect of physical activity (PA), recreational screen time (ST), and sleep in preventing childhood obesity. Hence, this study aimed to analyze the associations between meeting the PA, ST, and sleep recommendations within the 24-hour movement guidelines and adiposity indicators among children and adolescents. METHODS: A total of 679 children and adolescents aged 8-18 years were included. The time spent in moderate-to-vigorous PA and the sleep duration were estimated from raw data from a wrist-worn accelerometer. Recreational ST was reported by the child or parent. Body mass index (BMI) z-score, fat mass percentage (FM%), and visceral adipose tissue (VAT) were used as adiposity indicators. Participants with ≥ 60 min/day of moderate-to-vigorous PA, < 2 h/day of recreational ST, and uninterrupted sleep for 9-11 h/day (for children) or 8-10 h/day (for adolescents) were considered to meet the overall 24-hour movement guidelines. RESULTS: Meeting the ST only recommendation was associated with reduced odds of a high BMI z-score (odds ratio [OR] = 0.38, 95% confidence interval [CI]: 0.17-0.89), excess FM% (OR = 0.34, 95% CI: 0.13-0.93), and excess VAT (OR = 0.27, 95% CI: 0.10-0.74) in adolescents. Significantly reduced odds of a high BMI z-score was associated with meeting the combination of the ST and sleep recommendations (OR = 0.11, 95% CI: 0.01-0.89). Adolescents who met one recommendation (OR = 0.51, 95% CI: 0.27-0.96) or any two recommendations (OR = 0.33, 95% CI: 0.11-0.94) had reduced ORs of having a high BMI z-score. Adolescents had lower odds of having excess VAT if they met one recommendation (OR = 0.39, 95% CI: 0.19-0.81) or any two recommendations (OR = 0.25, 95% CI: 0.07-0.90). No significant associations were found in children. CONCLUSIONS: The present study showed no associations between meeting all three recommendations within the 24-hour movement guidelines and adiposity indicators. However, meeting ST only recommendation and the combination of the ST and sleep recommendations was associated with a reduced risk of excess adiposity. This finding should be considered when designing effective strategies and interventions to prevent childhood obesity.

Validity of Garmin Vívofit 1 and Garmin Vívofit 3 for School-Based Physical Activity Monitoring.

PURPOSE: Activity trackers are useful tools for physical activity promotion in adolescents, but robust validity evaluations have not been done under free-living conditions. This study evaluated the validity of the Garmin Vívofit 1 (G1) and Garmin Vívofit 3 (G3) in different settings and contexts. METHODS: The participants (girls: 52%, age: 15.9 [1.9] y) wore the G1 and G3 on their nondominant wrist and the Yamax pedometer on their right hip for a period of 1 week. Validity was examined in 4 discrete segments (before school, in school, after school, and whole day). The criterion method was the Yamax pedometer. RESULTS: Both the G1 and G3 could be considered equivalent to the Yamax pedometer regarding the before school, in school, and whole day segments. The G1 showed wider limits of agreement than G3. CONCLUSIONS: The G1 and G3 trackers exhibited acceptable validity for 3 of the 4 segments (before school, in school, and whole day measurements). The results were less accurate during the after-school segment. The evidence that the validity of the monitors varied depending on the setting and context is an important consideration for research on adolescent activity patterns.

Promoting Healthy Lifestyle and Well-Being in Adolescents through Outdoor Physical Activity.

Health-enhancing physical activities (PA) performed outdoors could markedly contribute to the adoption of a healthy lifestyle in adolescence. The differences between PA preferences and actual opportunities for these PA are an issue that has received frequent attention. To date, the extent to which these differences are reflected in adolescents meeting PA recommendations and their well-being has not been explored. In total, 10,086 respondents took part in an on-line research project regarding PA preferences. Of them, 2446 also completed the International Physical Activity Questionnaire (Long Form) and the World Health Organization (WHO) W-5 questionnaire to assess well-being. Finally, 1278 of these respondents were involved in objective PA monitoring using pedometers. The study aimed to explore the prevalence and trends regarding outdoor PA. Moreover, we assessed whether the agreement between preferred PA and PA actually undertaken was associated with higher odds for meeting PA recommendations and achieving a higher level of well-being. Of a selection of outdoor activities, Czech and Polish boys preferred cycling, swimming, and downhill skiing, while girls preferred swimming activities, skating, and cycling. The agreement between preferred and PA actually undertaken was associated with higher odds for meeting the weekly PA recommendations and higher levels of well-being both in boys and girls. Evaluation of outdoor PA preferences and taking these preferred activities into account when forming conditions for them was important in the efficient promotion of the physical and mental health of adolescents.