In February 2019 researchers from the USA published the results of their study to assess the association between sedentary behavior and physical activity on risk of atherosclerosis in a Mexican American population. Information on leisure time physical activity and sedentary behaviour (sitting during television/movies and total sitting) was collected via questionnaire. Ultrasound was used to measure the carotid intima-media thickness and also the presence of carotid plaque, a sign of atherosclerosis. Results showed no significant association between physical activity, sedentary behavior and intima-media thickness but there was a significant association between physical activity and sitting time during television/movie watching with the presence of carotid plaque. Those individuals who reported moderate levels of physical activity were found to have a significantly lower incidence of carotid plaque compared to those with no activity at all and in those sitting watching television/movies for over 3 hours/day. The researchers concluded that moderate physical activity should be undertaken to reduce the levels of carotid plaque and to avoid watching television/movies with a sitting time of more than 3 hours/day and/or having a total sitting time of over 8.5 hours/day.
Walker TJ et al. The combined effect of physical activity and sedentary behavior on subclinical atherosclerosis: a cross-sectional study among Mexican Americans. BMC Public Health. 2019 Feb 6;19(1):161.