We assessed the validity of the Physical Activity Scale for the Elderly (PASE) in a sample of sedentary adults (56 men, 134 women, mean age +/- [SD] 66.5 +/- 5.3 years) who volunteered to participate in a randomized controlled trial on the effect of aerobic conditioning on psychological function. Construct validity was established by correlating PASE scores with physiologic and performance characteristics: peak oxygen uptake, resting heart rate and blood pressure, percent body fat, and balance. The mean PASE scores were higher in men than in women (men = 145.8 +/- 78.0; women = 123.9 +/- 66.3, P < 0.05), and in those age 55-64 years compared with those age 65 years and over (55-64 = 144.2 +/- 75.8; 65 and over = 118.9 +/- 63.9, P < 0.05). PASE scores were also significantly higher in those who did not report a chronic health condition (cardiovascular disease, hypertension, cancer, or recent surgery). PASE scores were significantly associated (P < 0.05) with peak oxygen uptake (r = 0.20), systolic blood pressure (r = -0.18) and balance score (r = 0.20). No significant associations of PASE score and diastolic blood pressure, resting heart rate, or percent body fat were noted. These results provide additional evidence for the validity of the PASE as a measure of physical activity suitable for use in epidemiology studies on the association of physical activity, health, and physical function in older individuals. (C) 1999 Elsevier Science Inc.