The public health, medical, and research community has increased focus on childhood obesity over the past few decades and for good reason. Obesity prevalence is at an all-time high,1 and rates of severe obesity continue to increase.2 Activity, both sedentary and physical, are key contributors to the development and treatment of obesity.3–5 Increasing physical activity while decreasing sedentary activity is an obvious goal in improving the weight and health of children. Unfortunately, the majority of children in the United States are not receiving the recommended amounts of physical activity and surpassing suggested limits on sedentary activity.6 Because there are finite hours in a day, increasing time spent on 1 activity will require doing less of another (ie, replacing one activity with another). In the case of activity, it is assumed that increased time spent engaged in physical activity is always beneficial, without the recognition that it may detract from other important life and health components (eg, sleep and school work). Exploring how individuals allocate their time may provide insight into how one can increase time spent in a beneficial behavior (eg, exercise), without stealing that time from an activity that is also beneficial (eg, sleep).
In their study, Ng et al7 approached this topic through the lens of time and in relation to child health and well-being. The investigators used data from the Child Health CheckPoint Study, a part of the larger Longitudinal Study of Australian Children, a nationally representative birth cohort, drawing from later waves of the cohort when children were 11 to 12 years of age (N = 1179). An interesting, and rather holistic, set of outcomes were chosen and identified as important to children and families: adiposity (health), health-related quality of life (HRQoL) (physical and social health), and academic achievement (education). To capture time allocation, investigators used time-use epidemiology to investigate how time spent in different activities are related to health.8 Using compositional data analysis principles, they attempted to quantify the relationship between time spent in activities (specifically, sleep, sedentary activity, light physical activity, or moderate-vigorous physical activity [MVPA]), and health outcomes. Time use was captured by using accelerometry. The major findings were that time spent in MVPA was more potent than sleep or less time spent in sedentary activity, in relation to the outcomes of lower adiposity and higher HRQoL. In addition, less time spent in sedentary and light physical activity was also associated with lower adiposity and higher HRQoL. The authors concluded that, on the basis of minute-for-minute equivalents, MVPA was 2 to 6 times as potent as sleep or sedentary time for decreasing adiposity or improving HRQoL.
Systems science has highlighted the interconnectedness of social and environmental systems and how computational approaches to simulation and modeling can provide a deeper understanding of complex phenomena.9,10 The study by Ng et al is a great example of using novel approaches to understand how people live their lives and provide a new avenue to explore how activities interact with each other to affect our health and well-being. With only 24 hours in a day, how can we best use our time and benefit our health and overall well-being? How do individual experiences impact time allocation (ie, does experiencing weight bias influence sleep and other activities?)? Additionally, the inclusion of education and quality-of-life variables broadens the perspective of potential outcomes outside of weight: what value does an improved weight status have if educational achievement and overall quality of life are impaired? There are likely many more areas to include in future work, such as relationships, peers, family dynamics, and income, but this was an important first step into the investigation of the impact of time allocation among youth. When specifically thinking about changing children’s health behaviors, viewing recommendations in the context of competing demands of children’s and their families’ time can provide insight into how to modify family habits and schedules: parent work, children’s school and activity schedule, high expectations of scholastic achievement and participation in extracurricular activities for adolescents, bedtime routines, resource constraints, and priorities within the family will impact the ability of a child and family to modify their schedule to increase physical activity.
The variable of time allocation, and how activities are associated with outcomes of interest (in this study, adiposity, education, and quality of life), holds promise. Pertinent to childhood obesity, this could deepen the understanding of how families can enact change, literally down to the hour. Families can be guided to tweak where and how they spend their time, focusing on activities that have the biggest “bang for the buck.” The question is then how would a health care provider, registered dietitian, therapist, or coach do that? Much more information is needed in different countries, populations, and cultures on where to spend time, where to find that time, and how it impacts health and other important outcomes. A whole new set of skills would need to be developed to evaluate how families spend their time and then in how to guide them in time-allocation change. Educational materials and information on community resources could be offered on the basis of personalized patient needs. And thinking bigger, could accelerometry data be taken beyond research and into the clinical realm? Could time-use data be captured and incorporated into electronic medical records? Could prediction modeling, biomedical informatics, and time-use epidemiology all be used to gather more data on how people spend their time and predict what behaviors have the greatest impact on health and well-being? It is futuristic thinking for sure, but exciting nonetheless, and ripe for qualitative and quantitative research to explore.
Opinions expressed in these commentaries are those of the authors and not necessarily those of the American Academy of Pediatrics or its Committees.
FUNDING: No external funding.
COMPANION PAPER: A companion to this article can be found online at www.pediatrics.org/cgi/doi/10.1542/peds.2020-025395.
health-related quality of life
moderate-vigorous physical activity
POTENTIAL CONFLICT OF INTEREST: Dr Cardel reports grants from the National Institutes of Health National Heart, Lung, and Blood Institute and grants from WellCare Health Plans, Inc, during the conduct of the study and personal fees from WW (formerly Weight Watchers) and consulting with Novo Nordisk, for which she did not accept personal fees, outside the submitted work. Ms Newsome reports personal fees from Novo Nordisk outside the submitted work. Dr Skelton reports grants from the National Institutes of Health National Institute of Nursing Research and royalty payments from UpToDate as a contributor and peer reviewer not related to this submitted work.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.