A research team from the University of Hong Kong have found that replacing sedentary time with an equivalent amount of physically active time is associated with a lower risk of coronary heart disease, regardless of one’s genetic predisposition to the condition.
A research team led by Dr Youngwon Kim, Assistant Professor of Kinesiology from the School of Public Health at the Li Ka Shing Faculty of Medicine of the University of Hong Kong (HKU), in collaboration with the MRC Epidemiology Unit at the University of Cambridge School of Clinical Medicine, conducted a large-scale epidemiological study to examine the potential health benefits of substituting sedentary time for physically active time in preventing coronary heart disease across different genetic risk levels.
They found that replacing sedentary time, such as sitting, with an equivalent amount of physically active time is associated with a lower risk of coronary heart disease, regardless of one’s genetic predisposition to the condition. In particular, individuals with a higher genetic risk of coronary heart disease may experience a more significant reduction in their absolute risk of developing the disease compared to those with a lower genetic risk when substituting physical activity for sedentary time. These findings are published in the Journal of Internal Medicine [1].
Background
The World Health Organization (WHO) Guidelines underscore the importance of minimising sedentary behaviour for achieving optimal cardiovascular health. While excess sedentary time is recognised as a modifiable risk factor, it remains unclear whether replacing sedentary time with an equivalent amount of physical activity time is associated with lower risk of coronary heart disease across varying levels of genetic risk of coronary heart disease.
This research utilised extensive geno-type and phenotype data including wrist-worn wearable device data from the UK Biobank study which is an ongoing prospective UK cohort of over 500,000 adults. The current analysis included 77,500 white British participants (57% female) without prevalent cardiovascular events and with valid wrist-worn accelerometry data. Each individual’s genetic risk of coronary heart disease was assessed using polygenic risk scores based on 300 genetic variants. Sedentary time, light-intensity physical activity, and moderate-to-vigorous physical activity were quantified using wrist-worn wearable device data.
Three primary findings:
- Greater wearable-device-measured sedentary time is associated with an increased risk of coronary heart disease, regardless of genetic risk of coronary heart disease.
- Replacing 60 minutes/day of sedentary time with an equivalent amount of moderate-to-vigorous physical activity is associated with about 9% lower relative risk of coronary heart disease. Notably, even replacing as little as 1 minute/day of sedentary time with the same 1 minute/day of moderate-to-vigorous physical activity is associated with a <1% lower relative risk of coronary heart disease, across all levels of genetic risk.
- Replacing sedentary time with the same amount of moderate-to-vigorous physical activity may confer greater reductions in the absolute risk of developing coronary heart disease events in individuals at high genetic risk than in individuals at low genetic risk.
Significance of the study
“Our study provides unique insights into the role that replacing sedentary time (such as sitting time) with an equivalent amount of physical activity time could play in preventing coronary heart disease in individuals of varying levels of genetic risk of coronary heart disease. Our findings corroborate the current WHO recommendations on sedentary behaviour and physical activity, but suggest that, compared with individuals at low genetic risk of coronary heart disease, those at high genetic risk may have greater reductions in absolute risk of developing coronary heart disease by substituting physical activity for sedentary time,” said Dr Kim.
Reference:
- Kim, Y, Jang, H, Wang, M, et. al. Replacing device-measured sedentary time with physical activity is associated with lower risk of coronary heart disease regardless of genetic risk. J Intern Med. 2023; 00:1–13. https://doi.org/10.1111/joim.13715
