Leisure time physical activity and early atherosclerosis: the Los Angeles Atherosclerosis Study

Purpose Some studies of leisure time physical activity find a cardiovascular benefit for moderate activity, whereas others find benefit only for regular vigorous activity. We examined the relation between physical activity and 3-year progression of carotid atherosclerosis. Methods Baseline examinations were conducted during 1995 to 1996 with two follow-up examinations at 1.5-year intervals. Intima-media thickness of the common carotid arteries was determined by B-mode ultrasound in a cohort of 500 randomly sampled women and men, aged 40 to 60 years, who were asymptomatic for cardiovascular disease. Sedentary leisure activity was defined as the lowest quartile of a general activity measure, whereas vigorous activity was defined as aerobic activity ≥3.5 times per week. The remainder defined the moderate activity group. Analyses were adjusted for confounding variables. Results The mean (± SE) age- and sex-adjusted rates of progression of intima-media thickness declined from 14.3 ± 1.7 microns per year in sedentary subjects, to 10.2 ± 1.0 microns per year in moderately active subjects, to 5.5 ± 1.5 microns per year in vigorously active subjects (P for trend <0.0001), and remained statistically significant after adjustment for other confounding factors (P for TREND = 0.0004). Compared with the moderate activity group, the vigorous activity group had lower body mass index and resting heart rate and increased high-density lipoprotein cholesterol level, whereas the sedentary group had an increased resting heart rate. Workplace activity was not protective. Conclusion Physical activity during leisure is inversely related to the progression of atherosclerosis in the carotid artery. This benefit appears to increase throughout the activity continuum.