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Association of Reallocating Time in Different Intensities of Physical Activity with Weight Status Changes among
Kaiyun Tan1, Li Cai1, Lijuan Lai1
1Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
Insights
Promoting vigorous-intensity physical activity (VPA) in children is crucial. Replacing sedentary time with VPA significantly reduces the risk of childhood overweight and obesity.
Area of Science:
- Pediatric Health
- Exercise Physiology
- Public Health Nutrition
Background:
- Physical activity intensity and duration are codependent, impacting children's weight status.
- The specific substitution effects of different physical activity intensities on pediatric weight management remain under-researched.
- Understanding these relationships is vital for developing effective childhood obesity prevention strategies.
Purpose of the Study:
- To prospectively examine the association between reallocating time across different physical activity intensities and changes in weight status among Chinese children.
- To investigate the impact of substituting sedentary time with vigorous-intensity physical activity (VPA) on weight status.
- To provide evidence-based recommendations for promoting healthy physical activity patterns in children.
Main Methods:
- A national cohort of 15,100 normal-weight children (aged 7-18 years) was followed for nine months.
- Physical activity (VPA, MPA, walking, sedentary time) was assessed using the International Physical Activity Questionnaire Short Form (IPAQ-SF).
- Objective measurements of height and weight determined BMI and BMI z-score, with weight status classified using Chinese criteria. Isotemporal substitution analyses were employed.
Main Results:
- A 30 min/day increase in VPA was associated with a 13.2-15.6% reduced risk of developing overweight/obesity.
- Replacing 30 min/day of sedentary time with VPA favorably reduced the risk of overweight/obesity by 16.1%.
- Negative associations between VPA, MPA, walking, and underweight risk were observed in a single-factor model but not in the partition model.
Conclusions:
- Promoting vigorous-intensity physical activity is a key strategy for preventing overweight and obesity in children.
- Substitution of sedentary time with VPA demonstrates a significant protective effect on weight status.
- Public health initiatives should focus on increasing children's engagement in high-intensity activities.
Abstract:
Background: Time spent in different intensity-specific physical activities is codependent, but the substitution effect of different activities on weight status changes in children remains unclear. This study aims to investigate the prospective association between reallocating time in different intensities of physical activity and weight status changes among Chinese children. Methods: A national sample of 15,100 normal-weight children aged 7-18 years (46.7% boys) were recruited in September 2013 and followed up for nine months. Vigorous-intensity physical activity (VPA), moderate-intensity physical activity (MPA), walking, and sedentary time were obtained by International Physical Activity Questionnaire Short Form (IPAQ-SF). Height and weight were objectively measured, by which body mass index (BMI) and BMI z-score were calculated. Weight status was classified by the Chinese criteria for 7- to 18-year-old children. Isotemporal substitution analyses (including single-factor model, partition model, and isotemporal substitution model) were applied to examine the association of time allocation with weight status changes. Results: Each 30 min/day of increase in VPA was favorably associated with a 13.2% reduced risk of incident overweight/obesity in a single-factor model and a 15.6% reduced risk in a partition model. Negative associations were found between VPA, MPA, walking and the risk of being underweight in the single-factor model, but not in the partition model. In substitution models, replacing 30 min/day sedentary time with an equal amount of VPA was favorably associated with a 16.1% reduction of the risk of being overweight/obese. Conclusion: These findings highlight the need for promoting vigorous-intensity physical activity in children.
