Coronary artery calcium (CAC) scores are higher and progress faster in people who do more physical activity, but this does not mean exercise worsens atherosclerosis, cardiologists say.
A study of 25,485 healthy adults with at least two CAC measurements between 2011 and 2017 found physically active participants developed CAC faster and more frequently than inactive participants, regardless of baseline scores.
Published in the journal Heart, the Korean study reported that at baseline, 46.8%, 38% and 15.2% of people in an adult cohort undergoing health screening checks were inactive, moderately-active or took part in health-enhancing physically active (HEPA). Their average CAC scores were 9.45, 10.20 and 12.04, respectively. During a five year follow up period, the moderately-active and HEPA participants showed a 3.20 and 8.16 point increase in CAC over their inactive counterparts at five years.
While CAC scores greater than 0 are often associated with an increased risk of cardiovascular disease (CVD), the authors said their findings “should be interpreted with caution”.
Exercise has “undeniable” cardioprotective benefits and “the complex interplay between physical activity, CAC progression and subsequent CVD risk remains largely unknown”, they wrote.
Increasing CAC scores may indicate atherosclerotic plaque healing, stabilisation and calcification in these participants, which is associated with a lower CVD risk than mixed plaque development, they suggested.
Coronary atherosclerosis progression in physically active people may be driven by exercise-induced mechanical stress and vessel wall injury of coronary arteries, physiological responses, such as increased blood pressure, increased parathyroid hormone levels and changes in coronary haemodynamics and inflammation, they added.
Diet, vitamins and minerals may also change with physical activity, the authors noted.
“Our findings should not be interpreted as a harmful effect of physical activity, but, rather, need to be taken into account when evaluating the progression of CAC in patients who exercise to reduce cardiovascular risk,” they wrote.
Current Australian guidelines recommend 18–64 year-olds build up to 150–300 minutes of moderate physical activity, 75–150 minutes of vigorous physical activity, or an equivalent combination of the two, each week, to help reduce CVD risk.
“Although the implications of a positive association between physical activity and CAC in terms of cardiovascular events need to be established in future studies, our findings do not question the well-established cardiovascular benefits of physical activity,” the authors concluded.