The purpose of this study was to assess the heart rate (HR) and blood pressure (BP) response of sexual activity compared with treadmill exercise in adult men and women. Nineteen men, 55 +/- 8 years, and 13 women, 51 +/- 7 years, underwent a maximal Bruce protocol treadmill stress test followed by home-monitored sexual activity using noninvasive HR and BP recording devices. The mean treadmill times were significantly shorter than the mean times of sexual activity for men and women (p <0.001 and p = 0.002, respectively). For the men, average maximum HR, systolic BP, and HR-BP product during sexual activity were 72%, 80%, and 57% of respective measurements during treadmill exercise. For the women, maximum HR, systolic BP, and HR-BP product during sexual activity were 64%, 75%, and 48% of respective measurements during treadmill exercise. Age correlated inversely with duration of treadmill exercise (a 9-second decrease in duration per increasing year of age; p = 0.036), and with the duration of sexual activity (a 1-minute decrease in duration per increasing year of age; p = 0.024). Treadmill exercise duration predicted sexual activity duration (a 2.3-minute increase in sexual activity duration per each minute treadmill duration; p = 0.026). In conclusion, sexual activity provides modest physical stress comparable with stage II of the standard multistage Bruce treadmill protocol for men and stage I for women.