Effects of Physical Activity on Medical Expenses among Individuals with Obesity in Korea: Insights from a Nationwide Study

Background: Research on the relationship between physical activity and medical expenses among individuals with obesity has been sparse. This study investigates that association using nationwide data from Korea. Methods: We analyzed data from the National Sample Cohort of the Korean National Health Insurance Service, including 112,531 adults with obesity who underwent at least two health screenings within a 2-year interval between 2009 and 2015. Participants were categorized into four groups based on changes in their regular physical activity during 2 years: non-exercisers, quitters, starters, and maintainers. A two-part model was used to assess the average and excess annual medical expenses per person, including outpatient and hospitalization expenses. Results: Lower levels of physical activity correlated with an increase in both average and excess annual medical expenses per person (Pfor trend <0.001). Non-exercisers showed the highest average annual medical expenses per person, followed by quitters, starters, and maintainers. The most substantial increases in overall medical expenses were observed among quitters, followed by non-exercisers, starters, and maintainers. These associations were prominent in individuals aged ≥65 years and those with both type 2 diabetes mellitus and hypertension. Conclusion: In this nationwide study of individuals with obesity, lower physical activity levels were associated with increased medical expenses. Consistently engaging in physical activity might significantly lower medical expenses, particularly among elderly people and individuals with comorbidities. These findings highlight the importance of promoting sustained physical activity as a strategy for managing healthcare costs among individuals with obesity.