Sexuality survives in most men and women as long as they are alive, according to a study by the University of Chicago's National Social Life, Health and Aging Project (NSHAP).

Though sexual activity does decline with age, more than half of those aged 75-85 have sex at least 2-3 times a month; 23 percent have sex once a week. Oral sex was reported less frequently than intercourse.

The survey took a poll from 3,000 US adults aged 57-85.

About half of those surveyed reported at least one sexual problem (nearly a third reported at least two). For men, this most often meant problems maintaining an erection (37 percent); for women, a lack of interest (43 percent). However, those who were sexually active were also more likely to report better health.