 2. An interval of at least 4-6 weeks between prior radical prostatectomy and study enrollment. Radical prostatectomy-induced ED is an immediate and progressive disorder as such interventions shortly following surgery may be the most effective at attenuating this disorder. It is expected that men who have undergone radical prostatectomy will be fully recovered at 4-6 weeks post surgery and will be receptive to an exercise intervention study at this time capitalizing on the teachable moment. Additionally, the PI has demonstrated that maximal cardiopulmonary exercise testing is a safe, feasible, and acceptable assessment procedure 73 days post-craniotomy among 20 primary high grade primary brain tumor patients and 305 days post-pneumonectomy or lobectomy among 20 operable non-small cell lung cancer patients, 