Examining the relationship between physical activity levels and intensity and CVD risk Original paper

Research is clear that higher levels of physical activity are associated with lower risk for cardiovascular disease (CVD), at least within a range of physical activity. However, it’s not clear whether the reciprocal relationship between physical activity and CVD holds for the highest levels of physical activity or whether a threshold exists for physical activity intensity level. Previous research has relied on self-reported levels of physical activity, which tend to be unreliable. This study used accelerometer data to examine the associations between different levels of physical activity and CVD.

In this study of 90,211 participants without prior or current CVD in the UK Biobank cohort, physical activity was measured by accelerometer over a 7-day period in 2013-2015. The researchers assessed physical activity levels and grouped them by intensity levels to examine associations with CVD.

Higher levels of total physical activity were associated with lower CVD risk. Risk associations were similar across total, moderate, and vigorous intensity physical activity. These results do not support the idea that there’s a ‘ceiling’ for physical activity levels, after which the reduction in CVD risk levels off. That said, activity at the highest level appears to reduce CVD risk to the greatest extent.

Participants in the lowest category of physical activity tended to smoke more and have higher BMIs and inflammation levels as well as high blood pressure. Therefore, it can’t be ruled out that some of the association between physical activity and CVD risk could have been due to reverse causation.