The COVID-19 pandemic drastically altered lifestyles, limiting access to outdoor exercise and impacting mental well-being. A surge in the use of digital health technologies (DHTs) like fitness apps and wearables occurred concurrently. While some studies suggest a positive link between DHT use and health behaviors, the effectiveness remains controversial, with a lack of research on underlying mechanisms and a focus on adult populations. This study addresses these gaps by examining the impact of DHT use and social interaction on DHT platforms on healthy lifestyles and mental health among a nationally representative sample of Chinese students (aged 15-24). The study hypothesizes that both DHT use and social interactions on DHT platforms will be positively correlated with healthy lifestyles and mental health, and that behavioral regulation mediates these relationships.

Existing literature reveals high smartphone ownership and health app usage among adolescents. KEEP is the most popular DHT in China, offering features like exercise tracking and guidance. While DHTs show promise for health promotion, their efficacy is debated. Some meta-analyses report non-significant or even negative effects on health behavior change. The mediating role of self-regulation and the impact of social interaction via DHTs on adolescents' health are largely unexplored. The study builds on previous research that explores the use of DHTs for physical activity, weight management, and nutrition in adolescents and emphasizes the importance of healthy lifestyles (including diet, physical activity, and stress management) and mental health.

A nationwide questionnaire survey was conducted in China from May to June 2021, using a cluster-randomized sampling method. The survey included 3330 participants (aged 15-24), with 2297 valid responses after data cleaning. The survey measured participants’ demographics (gender, age, grade, BMI), DHT usage frequency and duration, social interaction on DHT platforms (sharing activity updates, discussing DHT use), behavioral regulation (using the BREQ questionnaire), healthy lifestyles (modified HPLP-S scale), and mental health (CESD-10 scale). Descriptive statistics, Pearson correlations, and mediation analyses (PROCESS version 3.5, Model 4) were used. The study employed four mediation models to test the hypotheses, using 5000 bootstraps to estimate confidence intervals. The significance level was set at 0.05.

The study found that both the use of DHTs (β = 0.188, p < 0.001) and social interactions on DHT platforms (β = 0.146, p < 0.001) positively predicted healthy lifestyles. Behavioral regulation mediated these relationships (Model 1: ab = 0.022, 95% CI = [0.016, 0.028]; Model 2: ab = 0.079, 95% CI = [0.062, 0.096]). Even after accounting for mediation, direct positive effects of DHT use and social interaction on healthy lifestyles remained significant. Regarding mental health, DHT use alone did not directly predict mental health (β = 0.002, p = 0.927), but social interaction on DHT platforms showed a positive association with depression (β = 0.119, p < 0.001), contrary to the hypothesis. However, behavioral regulation mediated the relationship between DHT use and mental health (ab = 0.009, 95% CI = [0.006, 0.012]) and between social interaction and mental health (ab = 0.030, 95% CI = [0.022, 0.039]). After considering mediation, DHT use showed a negative association with depression (β = -0.043, p = 0.039), while social interaction still had a positive association with depression (β = 0.064, p = 0.002). Behavioral regulation explained 42.69% and 72.01% of the total effect in models 1 and 2 respectively, and 22.75% and 46.24% in models 3 and 4 respectively. KEEP was the most frequently used DHT (75.9%), followed by smartwatches (39.1%). Exercise recording and guidance were the most commonly used functions.

The study's findings partially support the hypotheses, demonstrating that DHT use and social interaction influence healthy lifestyles, mediated by behavioral regulation. The unexpected negative correlation between social interaction and mental health warrants further investigation, potentially linked to seeking social support due to loneliness or the presence of negative interactions within online communities. The mediating role of behavioral regulation clarifies the complex relationship between DHT use and mental health. The direct positive effect of DHT use on healthy lifestyles is notable, even after accounting for behavioral regulation. The study's use of a large, national sample enhances the generalizability of findings. The results highlight the importance of behavioral regulation in health interventions using DHTs.

This study, using the BIT model, sheds light on the impact of DHT use and social interaction on Chinese adolescents' health. The findings emphasize the crucial role of behavioral regulation in mediating the effects of DHTs on both healthy lifestyles and mental health. The study offers valuable insights for designing effective health interventions using DHTs, promoting healthy behaviors, and improving mental well-being among adolescents. Future research should refine the measurement of social interaction and explore the influence of cultural and social factors, and employ longitudinal studies and randomized controlled trials to assess the long-term impact of DHTs on adolescent health.

The study's use of self-reported measures might introduce bias. The measurement of social interaction could be improved by differentiating between positive and negative interactions. Cultural and social factors impacting social interaction were not fully considered. Longitudinal studies are needed to assess the sustained impact of DHTs on behavior change. A randomized controlled trial would strengthen causal inferences.