J Med Internet Res. 2025 Jul 31;27:e69451. doi: 10.2196/69451.ABSTRACTBACKGROUND: Obesity has become one of today's global health challenges. According to the World Health Organization, in 2022, a total of 2.5 billion adults aged 18 years and older will be overweight, including more than 890 million adults with obesity.OBJECTIVE: Exercise interventions based on mobile health (mHealth) technology are widely available, but the effectiveness and feasibility of interventions using mHealth apps and exercise watches to improve the physical health of male college students with overweight and obesity are unknown, and this study compares the effects of online interventions carried out by mHealth technology and offline interventions guided by physical trainers on the physical health of male college students with overweight and obesity.METHODS: This study used a randomized controlled trial with a pretest-posttest design, and participants were randomly divided into an online group, an offline group, and a control group. The online group exercised online through the fitness app, and the offline group was instructed by a professional trainer to exercise offline, and both groups wore sports watches to monitor their activities, and the training content was the same. The control group did not carry out any intervention.RESULTS: At the end of the intervention, the BMI of the online and offline groups decreased by 0.89(SD 1.17) and 0.68(SD 0.94)kg/m², respectively (P