Key Research

Association of Physical Activity and Screen Time With Body Mass Index Among US Adolescents

Key Takeaways:

  • A combination of high screen time (hours per day) and low physical activity (step count per day) was associated with overweight and obesity.
  • High step count may not offset overweight and obesity risk for adolescents with high screen time;  low screen time may not offset overweight and obesity risk for adolescents with low step count.
  • Sixty (60) minutes of moderate to vigorous intensity physical activity per day is recommended for adolescents; however, in the last 5 years, the proportion of US adolescents meeting these guidelines decreased to lower than 25%, with subsequent reductions to lower than 10% during  the pandemic
  • Screen time of more than 4 hours per day and physical activity of less than 12 000 steps per day were associated with a higher risk of overweight or obesity among a racially diverse population-based sample of US adolescents

 

LiveMore ScreenLess’ Summary

While it is anecdotally known that there is correspondence between screen time and exercise, this study compared data from the massive ABCD study and number of steps each day as counted by wearable FitBit technology. Given that this was not self-reported data, the correlation uncovered is more reliable. 

The associations and interactions of physical activity and screen time categories with body mass index and overweight and obesity among adolescents was the question posed by this study.

It was found that high screen time and low activity leads to high BMI, which is unhealthy especially early in adolescents.  Additionally, it was found that even high step counts with high screen use did not offset the danger of obesity; the opposite is true as well, with low step count with low screen use.

Again, not surprisingly, the pandemic had a large impact on this population and study.

Nagata JM, Smith N, Alsamman S, et al. Association of Physical Activity and Screen Time With Body Mass Index Among US Adolescents. JAMA Netw Open. 2023;6(2):e2255466. 

Topics: Pandemic , Physical Health

Year: 2023

Participants: cross-sectional study of 5797 US adolescents aged 10 to 14 years

Data Collection: Adolescent Brain Cognitive Development (ABCD) Study, 2018 – 2020; 21 racially and ethnically diverse study sites across US