A recent systematic review and meta-analysis highlights the potential of wearable activity trackers to promote physical activity among children and adolescents.
The study, published in the Lancet Digital Health, reviewed 21 trials with 3,676 participants, averaging 13.7 years old. Researchers found that wearable trackers significantly boost daily physical activity, measured by step counts, although they did not observe a similar improvement in moderate-to-vigorous physical activity levels.
These findings suggest that wearable trackers could serve as a valuable tool to encourage physical activity in young people. However, more research is needed to confirm these results and explore long-term effects.
The study received funding from the Hong Kong University Grants Committee and the University of Hong Kong.
Importance of the study
Physical activity is crucial for the health and well-being of children and adolescents, yet many young people are not meeting the World Health Organization’s (WHO) recommended 60 minutes of moderate-to-vigorous physical activity daily.
A global study from 2016 revealed that less than 20% of adolescents aged 11–17 met these guidelines. The situation worsened during the COVID-19 pandemic due to social isolation. The decline in physical activity begins around age 10 and continues through adolescence, leading to serious long-term health risks, including obesity, heart disease, and type 2 diabetes.
Interventions that encourage self-monitoring, such as wearable activity trackers, may help increase physical activity levels in young people. These devices, which track metrics like daily step count and exercise intensity, have shown success in promoting physical activity in adults, but their effectiveness in children and adolescents remains unclear. Past studies offer mixed results. For instance, some research suggests that wearable trackers have little impact on increasing physical activity among young users, while other studies report positive outcomes, particularly in healthy populations.
However, many of these studies have methodological flaws, such as a lack of randomization or control groups, which raises questions about the reliability of their findings. Some studies excluded clinical populations (e.g., children with obesity or chronic illnesses), limiting the generalizability of the results. Additionally, inconsistencies in data collection methods may have skewed the outcomes.
This systematic review and meta-analysis aimed to provide a more comprehensive assessment of the impact of wearable activity trackers on physical activity in both healthy and clinical populations of children and adolescents. By including a broader range of studies and addressing previous limitations, this research seeks to offer clearer insights into how wearable trackers can help young people achieve healthier activity levels.
Methodology
Researchers set out to evaluate the effectiveness of wearable activity trackers in promoting physical activity among children and adolescents. The study searched major databases like PubMed, Embase, SPORTDiscus, and Web of Science for relevant publications up to August 2023, screening thousands of studies for eligibility.
The review included randomized controlled trials (RCTs) and cluster-RCTs that featured wearable trackers aimed at increasing physical activity, reducing sedentary behavior, or improving overall health in young populations. The study applied a rigorous selection process using the PICOS framework to ensure the inclusion of studies that tracked physical activity objectively and provided clear comparisons between intervention and control groups.
Researchers analyzed key outcomes such as daily steps and moderate-to-vigorous physical activity, along with secondary measures like accelerometer counts, light physical activity, and sedentary time. Data extraction and analysis followed strict protocols, using tools like Covidence software and R statistical packages to calculate effect sizes and assess risk of bias.
To explore the effects of wearable trackers across various settings and populations, the study conducted subgroup analyses, considering factors such as age, gender, health status, and intervention strategies. Researchers also assessed the potential for publication bias and addressed it through sensitivity analyses.
Outcomes
Researchers conducted a comprehensive systematic review and meta-analysis involving 21 studies with a total of 3,676 children and adolescents, averaging 13.7 years in age. These studies assessed the impact of wearable activity trackers on physical activity. Most studies used pedometers, though some employed Fitbits and accelerometers.
Primary Outcomes:
- Daily Steps: Wearable trackers significantly increased daily steps compared to control groups, with a standardized mean difference (SMD) of 0.37. However, sensitivity analyses indicated that this effect became non-significant after removing studies with a high risk of bias or when correcting for publication bias through trim-and-fill analysis.
- Moderate-to-Vigorous Physical Activity (MVPA): There was no significant improvement in objectively measured MVPA at the post-intervention stage (SMD = -0.08). Similarly, no significant effect was observed during follow-up periods.
Secondary Outcomes:
- Other Physical Activity Measures: No significant effects were found for secondary outcomes, which included accelerometer counts per minute (CPM), light physical activity, subjectively measured MVPA, and sedentary time, at both post-intervention and follow-up timepoints.
Subgroup and Sensitivity Analyses:
- Subgroup Analyses: These did not reveal significant variations based on participants’ mean age or study duration for daily steps or MVPA.
- Sensitivity Analyses: For daily steps, the effect size remained significant after removing statistical outliers, though it became non-significant after excluding studies with high risk of bias. For MVPA, sensitivity analyses did not change the outcome, as there were no outliers identified.
Risks of bias
Significant publication bias was detected for both daily steps and MVPA. Trim-and-fill analyses showed a non-significant effect for daily steps but confirmed the initial findings for MVPA, with a slight decrease in the effect size.
- Risk of bias: Varied across studies, with assessments detailed in the supplementary materials.
- GRADE Assessment: The certainty of evidence for daily steps was rated low, while for MVPA, it was rated high, reflecting the robustness of the findings in the latter outcome.
While wearable activity trackers modestly increased daily steps, they did not significantly boost more vigorous forms of physical activity, raising questions about their effectiveness in promoting higher-intensity activities in children and adolescents. The reliability of these findings, particularly for daily steps, was influenced by study quality and publication bias, highlighting the need for cautious interpretation.
