Fifty healthy women between the ages of 40 and 65 participated in a 12-week program of exercise, discussion sessions, or both. Levels of serum cholesterol, triglycerides, total high-density lipoprotein (HDL), HDL-cholesterol, and HDL-2b were monitored at baseline and at six and 12 weeks. Cardiorespiratory function was assessed at baseline and 12 weeks. Women participating in the exercise groups had smaller increases in serum cholesterol (P less than .05) and greater increases in maximal oxygen consumption, time spent on a treadmill, and time required to attain 90% of maximal oxygen consumption (P less than .01) than the nonexercising women. No statistically significant differences were observed in levels of serum triglycerides, total HDL, or HDL-cholesterol fractions between nonexercising and exercising groups at either six or 12 weeks.