The extent to which exercise can delay the normal decline in physical performance associated with aging is unknown. We examined the impact of 2 years of supervised exercise on cardiovascular fitness, flexibility, and strength in a group of elderly (age 65-74) veterans. Seventy-five patients exercised 3 days/week for 90-minute sessions emphasizing aerobic, flexibility, and strength development. Thirty-six (47%) completed 2 years of a voluntary supervised exercise program (n = 25 with complete data). Over a 2-year follow-up period, cardiovascular outcome variables improved significantly: metabolic equivalents increased 20% (7.4 +/- 2.2 to 9.0 +/- 2.4, P less than 0.001) and submaximal heart rate decreased 7% (68.5 +/- 8.0 to 63.6 +/- 8.4 beats/minute, P = 0.02). Resting heart rate decreased 8% (131.4 +/- 14.8 to 121.0 +/- 18.5 beats/minute, P = 0.06), but this difference did not reach statistical significance. Flexibility, measured by hamstring length, improved 11% (57.5 +/- 15.1 to 64.0 +/- 11.1 degrees, P = 0.02). Strength variables did not improve. The study indicates that improvements in cardiovascular function and flexibility achieved by the elderly in the early stages of an exercise program can be maintained for at least 2 years.