Can incidental physical activity offset the deleterious associations of sedentary behaviour with major adverse cardiovascular events?

AIMS: Incidental physical activity as part of daily living may offer feasibility advantages over traditional exercise. We examined the joint associations of incidental physical activity and sedentary behaviour with major adverse cardiovascular events (MACE) risk. METHODS AND RESULTS: Analyses included 22 368 non-exercising adults from the UK Biobank accelerometry sub-study (median age [IQR]: 62.9 [11.6] years; 41.8% male). Physical activity and sedentary behaviour exposures were derived using a machine learning-based intensity and posture classification schema. We assessed the tertile-based joint associations of sedentary behaviour and the following: a) incidental vigorous (VPA), b) incidental moderate to vigorous (MVPA), c) vigorous intermittent lifestyle physical activity (VILPA; bouts lasting up to 1 min), and d) moderate to vigorous intermittent lifestyle physical activity (MV-ILPA; bouts lasting up to 3 min) with MACE risk. Over an 8.0-year median follow-up, 819 MACE events occurred. Compared to the highest physical activity and lowest sedentary time, high sedentary behaviour (>11.4 h/day) with low incidental VPA (<2.1 min/day) had an HR of 1.34 (95% CI: 0.98, 1.84) and low incidental MVPA (<21.8 min/day) had a 1.89 HR (95% CI: 1.42, 2.52) for MACE. Sedentary behaviour was not associated with MACE at medium and high levels of VPA or VILPA. Completing 4.1 min/day of VPA or VILPA may offset the MACE risk associated with high sedentary behaviour. Conversely, 31-65 min of incidental MVPA or 26-52 min of MV-ILPA per day largely attenuated the associations with MACE. CONCLUSION: Brief intermittent bursts of vigorous incidental physical activity may offset cardiovascular risks from high sedentary behaviour. LAY SUMMARY: Literature to date has examined the role of total or leisure time physical activity in mitigating the health risks associated with high sedentary behaviour. However, the vast majority of adults achieve their daily physical activity incidentally through day-to-day activities. In this study of 22 368 adults from the UK Biobank accelerometry sub-study, we provide the first investigation into whether a) incidental vigorous (VPA), b) incidental moderate to vigorous (MVPA), c) vigorous intermittent lifestyle physical activity (VILPA; bouts lasting up to 1 min), and d) moderate to vigorous intermittent lifestyle physical activity (MV-ILPA; bouts lasting up to 3 min) completed through normal daily living can offset the risk of major adverse cardiovascular events (MACE) associated with high sedentary behaviour (>11.4 h per day). We demonstrate that incidental VPA and MVPA may offset the MACE risk associated with high-sedentary behaviour even if accrued in brief bursts lasting <3 min. Completing 4.1 min/day of VPA or VILPA may offset the MACE risk associated with high sedentary behaviour.A daily duration of 31-65 min of incidental MVPA or 26-52 min of MV-ILPA per day largely attenuated the associations with MACE.