Persons with sedentary jobs have been shown to have an increased risk of cardiovascular morbidity and mortality compared with those who have active jobs. Because of the movement in the job environment to more sedentary activities, the amount of self-reported activity during leisure time has been shown to have a positive effect on cardiovascular risk. Even light to moderate physical activity in women has been shown to provide some cardiac protection. Results of studies examining the protective impact of physical activity on subclinical atherosclerosis have been mixed. Nordstrom and colleagues evaluated the relationship between physical activity during work and leisure time on the progression of subclinical atherosclerosis in middle-aged men and women.

The trial was a longitudinal study of utility company employees between 40 and 60 years of age. The exclusion criteria were a self-reported history of cardiovascular disease and current treatment for cancer. Participants in the study were randomly selected from all employees and assessed for intima-media thickness of the common carotid arteries by B-mode ultrasound scans at baseline and at 1.5 years and 3 years after the start of the study. Physical activity was assessed at the three examinations by a nurse-assisted questionnaire. Physical activity levels were divided into three categories—sedentary, moderate, and vigorous. The sedentary group included those who were in the lowest quartile of the general activity measure. Vigorous activity included those who participated in aerobic activity 3.5 times per week or more. Moderate activity included those who did not meet the sedentary or vigorous activity definitions. Other measurements included blood pressure, anthropometric measures, and fasting serum and plasma samples.

Of the 500 persons who participated in the study, 54 percent (268 persons) were men, and the average age of the participants was 50 years. Twenty-four percent (120 persons) of the participants were identified as current smokers, and 27 percent (135 persons) as former smokers. Vigorous activity levels were correlated with total and leisure activity but not with work activity. The intima-media thickness over the three-year period was 5.5 microns among those in the vigorous activity group, 10.2 microns in the moderate group, and 14.3 microns in the sedentary group. This was a significant difference for the trend when controlling for sex and age variables.

The vigorous activity group had a lower body mass index, a slower resting heart rate, and an increase in high-density lipoprotein cholesterol compared with persons in the moderate activity group. The sedentary group had a higher resting heart rate compared with persons in the moderate activity group.

The authors conclude that physical activity during leisure time has a strong inverse relationship to the progression of subclinical atherosclerosis in the carotid arteries. They add that vigorous activity provides the best results but that even moderate activity provides benefits. Therefore, even moving patients from a sedentary leisure lifestyle to moderate activity levels would reduce the progression of atherosclerosis.