Joint associations of leisure-time physical activity and sitting time with emotional wellbeing, physical functioning and work ability: an occupational study among young and early midlife Finnish municipal employees

Background Physical inactivity and sedentary behaviour are major public health problems. We examined the individual and joint associations of leisure-time physical activity (LTPA) and total sitting time with emotional wellbeing, physical functioning and work ability in young and early midlife employees. Methods Cross-sectional questionnaire survey data were collected in 2017 among 19–39-year-old employees of the City of Helsinki (response rate 51.5%). LTPA (including commuting PA) was converted into a metabolic equivalent (MET) index. We classified the participants into four groups according to PA recommendations and participation in vigorous intensity activities. Total sitting time was classified into three groups using tertile cut-points (5.5 and 8.5 h/day). For joint analyses, we truncated LTPA into three groups and sitting time into two groups yielding a six-category variable. Emotional wellbeing and physical functioning were measured using the RAND-36 questionnaire and work ability with a scale ranging from 0 to 100. Linear regression analysis was used to estimate adjusted means and their 95% confidence intervals (CIs). The analytical sample included 4544 participants (80% females). Results Adjusting for age and sex, high sitting time (> 8.5 h/day) was associated only with poorer emotional wellbeing. LTPA, especially vigorous activity, showed clear positive associations with emotional wellbeing, physical functioning and work ability. For emotional wellbeing, the low activity groups with low (70.51, 95% CI 69.1–71.9) and high (67.5, 65.5–69.5) sitting time and the moderate activity groups with low (72.5, 71.3–73.7) and high (70.4, 68.6–72.1) sitting time had statistically significantly lower mean scores than the corresponding vigorous activity groups with low (74.9, 74.2–75.7) and high (72.7, 71.6–73.9) sitting time. For physical functioning, the vigorous activity groups with low (96.3, 95.8–96.7) and high (96.2, 95.5–96.9) sitting time had significantly higher scores than the other groups. For work ability, the vigorous activity groups with low (82.0, 81.3–82.6) and high (80.8, 79.8–81.8) sitting time had significantly higher scores than the other groups. Adjusting for covariates only slightly attenuated these associations. Conclusions Promoting PA among employees can contribute to better physical and mental health as well as better work ability.