The over-50s who are still very frisky between the sheets: Study finds pensioners well into their 80s still have an active sex life A quarter of 75 to 85-year-olds have had sex within the last year A third of 75 to 85-year-olds have given or received oral sex in the last year Old people in good health are twice as likely to be sexually active as those in poor health - and men are more likely to be having sex than women Half of over-55s who are still having sex experience sexual problems - such as erectile dysfunction - and 34 per cent of women couldn't orgasm Few people want to think about their parents, or even grandparents, having sex. Now, research suggests that if you don't want to be shocked, you shouldn't ask. The study found that a quarter of 75 to 85-year-olds have had sex within the last year - as have three-quarters of 57 to 64-year-olds, and half of 64 to 75-year-olds. A quarter of 75 to 85-year-olds have had sex within the last year - as have three-quarters of 57 to 64-year-olds, and half of 64 to 75-year-olds It also revealed that a third of 75 to 85-year-olds have given or received oral sex in the last year, NBC News reports. The research, to be published in the New England Journal of Medicine, showed older people are surprisingly active between the sheets. It showed that people's interest in sex does decline when they are in their 70s but that many continue to enjoy fun in the bedroom long after this. It also revealed that many of the people who do stop having sex do so because of poor health or the lack of a partner, rather than because they want to. The researchers interviewed 3,005 men and women from across the U.S. They discovered that at all ages women were less likely to be sexually active than men, but that this was partly because they were more likely to lack a partner. Half of those still having sex reported having at least one sexual problem - 37 per cent of the men had erectile dysfunction and 43 per cent of the women had low levels of desire People who were in good health were also twice as likely to be having sex as those in poor health. There were, however, signs that age was taking its toll on some of the volunteers. Half of those still having sex reported having at least one sexual problem - 37 per cent of the men had erectile dysfunction and 43 per cent of the women had low levels of desire. Some 34 per cent of the sexually active women also said they were unable to orgasm. "This subject has been taboo for so long that many older people haven't even talked to their spouses about their sexual problems, let alone a physician," lead author, Dr Stacy Tesser Lindau, from the University of Chicago, told NBC News. Elderly people today might be more mentally nimble than their counterparts a decade ago, according to a new European study. Researchers found people who were in their 80s when they took thinking and memory tests in the late 2000s performed similarly to others who were tested more than 10 years earlier while in their 70s. Scientists tested the thinking and memory skills of 204 elderly French men and women selected from the memory clinic of a Paris hospital between 1991 and 1997. They compared their test scores to those from 177 people tested at the same clinic in 2008 and 2009. As expected, people under age 80 performed better on the cognitive tests than older participants during both study periods, researchers led by Jocelyne de Rotrou from Hôpital Broca in Paris wrote in PLOS One. The 2000s group as a whole also did better than the 1990s group. Participants tested more recently scored an average 83.2 out of a possible 100 on the exams, compared to 73.5 for their earlier counterparts. The differences were consistent across almost every component of the tests, including how well people remembered stories and pictures and their ability to separate objects into different categories. The authors said this trend might simply parallel increased life expectancies - the longer you live, the more good years you have. But there could be something else going on too, according to Reuters Health, like improvements in the average person's education and socioeconomic status. "The idea that some people will get extra years of healthy living before they get dementia, that's important," Dallas Anderson, from the Institute of Aging in Maryland, said. When you look at it from a public health perspective, it's huge. But the trend might not continue, he said, especially in the U.S. as more obese, diabetic generations age into retirement. Their health problems could help speed mental decline. "Even if the rates go down, the numbers are still going to go up," he said.