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 > or = 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.