The goal was to determine the existence of differential effects of long-term moderate- or low-intensity exercise on selected bio-behavioral variables in 72 community-dwelling persons over 60 years of age. After screening, subjects were randomly assigned to a moderate (n=39, 60–70% heart rate reserve [HRR]) or low (n=33, 30–40% HRR) intensity exercise protocol. Both groups exercised three times per week for 9 months and dependent measures were taken at baseline, 4.5 months and after 9 months. Repeated measures ANOVA with Tukey post hoc comparisons constituted the analysis approach. Moderate exercise showed no superiority over low-intensity exercise; both groups improved about equally. Variables that significantly improved included: self-reported sleep (sleep quantity and dream recall), mental status (attention/concentration, short-term memory and higher cognitive functioning), health perceptions (health outlook, health worry, rejection of the sick role), and cardiovascular fitness indicators (submaximum stress test heart rate, maximum oxygen consumption (VO2max), maximum work capacity and maximum exercise time). Similarity of outcomes in both groups may mean that the moderate exercise protocol was too conservative. Conversely, the findings may indicate that lower levels of exercise, which may be safer and more feasible over time, do improve fitness levels, prolong independent functioning, and promote positive perceptions of well-being in older adults.