Cardiovascular Responses to Occupational Physical Activity are Exaggerated by Work-Related Stress and Low Fitness

Objectives Paradoxical associations between high occupational physical activity (OPA) and cardiovascular disease may be explained by exaggerated cardiovascular responses from high work-related stress or low worker fitness. Methods OPA, blood pressure (BP), heart rate (HR), and rate-pressure product (RPP; HR × BP) were measured objectively for 24 hours in 19 male workers. Work-related stress was measured using the Stress in General Scale. Fitness was estimated using a submaximal treadmill test. Effect modification by work-related stress and fitness on associations between OPA and cardiovascular responses was examined using mixed models with interactions. Results Associations between OPA and RPP, HR, and BP were stronger with high stress ( P < 0.05). Associations of work-time moderate and vigorous physical activity and RPP were attenuated with higher fitness ( P < 0.05). Conclusions OPA performed under high work-related stress or by workers with low fitness may exaggerate cardiovascular responses to OPA.