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: 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: a) incidental vigorous (VPA), b) incidental moderate to vigorous (MVPA), c) vigorous intermittent lifestyle physical activity (VILPA; bouts lasting up to 1 minute), and d) moderate to vigorous intermittent lifestyle physical activity (MV-ILPA; bouts lasting up to 3 minutes) with MACE risk. RESULTS: 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 hours/day) with low incidental VPA (<2.1 minutes/day) had an HR of 1.34 (95% CI: 0.98, 1.84) and low incidental MVPA (<21.8 minutes/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 minutes/day of VPA or VILPA may offset the MACE risk associated with high sedentary behaviour. Conversely, 31-65 minutes of incidental MVPA or 26-52 minutes 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.