Association between long working hours and physical inactivity in middle-aged and older adults: a Korean longitudinal study (2006-2020)

BACKGROUND: We investigated associations for long working hours in relation to physical inactivity and high-level physical activity among middle-aged and older adults. METHODS: Our study included 5402 participants and 21 595 observations from the Korean Longitudinal Study of Ageing (2006-2020). Logistic mixed models were used to estimate ORs and 95% CIs. Physical inactivity was defined as not engaging in any type of physical activity, while high-level physical activity was defined as engaging in ≥150 min per week of physical activity. RESULTS: Working >40 hours weekly was positively related to physical inactivity (OR (95% CI) 1.48 (1.35 to 1.61)) and negatively related to high-level physical activity (0.72 (95% CI 0.65 to 0.79)). Exposure to long working hours consecutively for ≥3 waves was associated with the highest OR for physical inactivity (1.62 (95% CI 1.42 to 1.85)) and the lowest OR for high-level physical activity (0.71 (95% CI 0.62 to 0.82)). Furthermore, compared with persistent short working hours (≤40 hours → ≤40 hours), long working hours in a previous wave (>40 hours → ≤40 hours) were associated with a higher OR of physical inactivity (1.28 (95% CI 1.11 to 1.49)). Exposure to an increase in working hours (≤40 hours → >40 hours) was also associated with a higher OR of physical inactivity (1.53 (95% CI 1.29 to 1.82)). CONCLUSION: We found that having working long hours was associated with a higher risk of physical inactivity and a lower likelihood of high-level physical activity. Moreover, accumulation of long working hours was associated with a higher risk of physical inactivity.