Accepted: 25 July 2017 DOI: 10.1002/ajim.22756 RESEARCH ARTICLE Physical activity and 22-year all-cause and coronary heart disease mortality Niklas Krause MD, MPH, PhD 1,2 | Onyebuchi A. Arah MD, MSc, DSc, MPH, PhD 2 | Jussi Kauhanen MD, PhD 3 1 Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles (UCLA), California 2 Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), California 3 Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland Correspondence Niklas Krause, University of California Los Angeles, 650 Charles E. Young Dr. South, 56- 071 CHS, Box 961772, Los Angeles, CA 90095-1772. Email: niklaskrause@ucla.edu Background: This study explores the effects of occupational (OPA) and leisure time physical activity (LTPA) on mortality relative to cardiorespiratory fitness and pre- existing coronary heart disease (CHD). Methods: Associations between OPA, measured as energy expenditure (kcal/day) and relative aerobic workload (%VO 2 max), LTPA, and 22-year mortality among 1891 Finnish men were assessed by Cox regression models stratified by CHD and adjusted for 19 confounders. Results: In fully adjusted models, each 10% of relative aerobic workload increased all- cause mortality by 13% and CHD mortality 28% (P < 0.01). Compared to healthy subjects, men with CHD experienced lower mortality risks due to OPA and higher risks due to LTPA. While LTPA had no effect among healthy men, in men with CHD each weekly hour of conditioning LTPA increased all-cause mortality risks by 10% and CHD mortality by14%. Conclusion: OPA was positively associated with both all-cause and CHD mortality. LTPA was not protective. Among men with CHD, LTPA increased mortality risks. KEYWORDS cardiorespiratory fitness, energy expenditure, physical workload, prospective study, relative aerobic workload 1 | INTRODUCTION The beneficial effects of leisure time physical activity (LTPA) on the circulatory system are well established, 1 but the literature on the health effects of occupational physical activity (OPA) remains inconsistent. 2 A meta-analysis of 21 prospective studies published between 1980 and 2010 concluded that both LTPA and moderate levels of OPA were beneficial for cardiovascular health. 1 In contrast, an updated meta-analysis of 23 prospective cohort studies published between 2011 and 2013 concluded that moderate and high levels of OPA are associated with an increased cardiovascular disease (CVD) risk. 3 Similarly, studies on CVD mortality and all-cause mortality have shown negative (eg, refs. 4–8 ), no (eg, refs. 4,9–14 ), and positive (eg, refs. 15,16–19 ), associations with OPA. Several studies provide direct evidence for a paradoxical effect of physical activity where LTPA appears beneficial and OPA detrimental to cardiovascular health and longevity in the same study population. 15,20–22 Other studies indicated a u-shaped dose-response relationship between OPA and mortality with elevated risks associated with both sedentary and heavy work. 23–25 A recent study found OPA to be beneficial but heavy lifting work to be detrimental, especially if combined with low OPA and low LTPA pointing to interactions between different types of physical activity. 26 Further, interactions of OPA with physical fitness reported for coronary heart disease (CHD) mortality 27 indicate that a discrepancy of physical job demands and individual aerobic work capacity (cardiore- spiratory fitness) may determine the health effects of OPA. This has Performance site: University of California, Los Angeles. Am J Ind Med. 2017;1–15. wileyonlinelibrary.com/journal/ajim © 2017 Wiley Periodicals, Inc. | 1