Dose Response of Incidental Physical Activity Against Cardiovascular Events and Mortality

Area of Science:

• Cardiology
• Public Health
• Exercise Science

Background:

• Limited engagement in leisure-time exercise among middle-aged and older adults.
• Incidental physical activity (IPA) offers an alternative for increasing daily movement.
• Lack of dose-response data for IPA interventions and guidelines.

Purpose of the Study:

• To examine the association between device-assessed IPA intensities (vigorous [VIPA], moderate [MIPA], light [LIPA]) and major adverse cardiovascular events (MACE) and mortality.
• To estimate the "health equivalence" of LIPA and MIPA relative to VIPA.

Main Methods:

• Analysis of 24,139 nonexercisers from the UK Biobank accelerometry substudy (ages 61.9±7.6 years).
• Calculation of IPA energy expenditure and daily durations using a machine learning-based intensity classifier.
• Prospective cohort design with follow-up for MACE, CVD mortality, and all-cause mortality.

Main Results:

• IPA volume showed an L-shaped association with reduced MACE, CVD mortality, and all-cause mortality.
• Any VIPA or MIPA was linked to lower risk, with optimal benefits plateauing around 14 min/day (VIPA) and 34-50 min/day (MIPA).
• One minute of VIPA was equivalent to 2.8-3.4 min of MIPA or 34.7-48.5 min of LIPA in terms of cardiovascular risk reduction.

Conclusions:

• Daily incidental physical activity, particularly vigorous and moderate intensities, is associated with reduced cardiovascular risk.
• Light-intensity IPA showed weaker associations, significant only for CVD mortality at higher durations.
• IPA presents a valuable strategy for improving cardiovascular health, especially for individuals unable to participate in structured exercise.