Although there is wide variability, at this point males generally are only half as sexually active as they were at the peak of their capacity in their late teens and early twenties. During the late 40s and increasing gradually thereafter, the urgency of sexual interest declines, erection is less frequent and more difficult to sustain, the turgidity of the erection diminishes, ejaculation is less forceful, and refractory time is lengthened. After age 40, many men begin to experience periodic inability to achieve an erection and the frequency of this incapacity increases over time and becomes quite common by the 60s. However, although by the 60s all of the changes noted above are quite noticeable in almost all men, the pleasure they derive from sex may not be significantly affected. Thus it is not completely surprising to discover that, in recent years, elderly men in senior housing apartments have become a regular source of clients among prostitutes.
Various factors can limit sexual interest and capacity in men as they age.
There are a number of organic problems of the heart and circulatory system, glands and hormonal system, and the nervous system that can, to varying degrees, diminish male capacity for and interest in sex. And the side effects of many medications used to treat some of these organic conditions can themselves compound the problem. Masters and Johnson originally reported that as much as 90 percent of male impotence has a psychological origin. Due to more sophisticated urological testing procedures it is now estimated that only about 40 percent of erectile problems are purely psychological. The majority of causes of male impotence have their origin in hormonal, vascular or neurological factors.