Effectiveness of lower-level voluntary exercise in disease prevention of mature rats. I. Cardiovascular risk factor modification.

To evaluate the chronic effects of voluntary exercise at lower levels on primary cardiovascular risk factors, inactive strain male Fischer rats were housed either with or without free access to activity wheels under controlled environmental conditions. The average amount of exercise for the 35-week duration was 722 (SD 362) m.day-1.rat-1, which was among the lowest found in the existing reports. Nonetheless, the body mass gains of the exercising rats were markedly inhibited, being 13% less (P < 0.001) than those of the sedentary controls, despite a 22% increase in food consumption (P < 0.0001), suggesting a remarkable prevention of adiposity. A noticeable improvement of serum lipid profiles was also found; a 53% reduction in triglyceride concentrations (P < 0.01) and a 13% increase in high density lipoprotein cholesterol concentrations (P < 0.05). In addition, resting systolic blood pressure was lowered by 7% (P < 0.01). These results would suggest that even lower-level physical activity, if continued regularly, will attenuate the age-related development of cardiovascular risk factors associated with a sedentary lifestyle.