Troubled by wrinkles around your eyes? Worried that your skin is sagging, or those gray hairs are making you look your age?
So have sex.
Making love three times a week can make you look 10 years younger, claims a Scottish researcher.
"It's good for you to have good sex," says David Weeks, a clinical neuropsychologist at the Royal Edinburgh Hospital, whose study on the effects of sex on aging appears in his book, Secrets of the Superyoung.
Over the last 10 years, Weeks and his colleagues interviewed 3,500 European and American men and women on a variety of lifestyle topics. Participants ranged in age from 20 to 104, but most were 45 to 55 years old.
The thing they had in common: They looked young for their age. That's what a six-judge panel decided after watching the interviewees through a one-way mirror. The volunteer judges guessed the participants' ages from seven to 12 years younger than their actual ages, Weeks says.
Interview topics ranged from how they deal with stress within relationships, how they get along with their parents and high and low points of their lives, to prior sexual experiences, how often they had sex and whether they enjoyed it.
A vigorous sex life, Weeks says, was the second-most important determinant of how young a person looked. Only physical activity proved more important than sex in keeping aging at bay, he says.
Other major influences on keeping a person young-looking included socializing with people of all ages, being married to or in a relationship with someone younger and, for women, taking hormone replacement therapy during menopause, Weeks says.
So, how often should you do it?
The young-looking participants had sex an average of three times a week, Weeks says. By comparison, a group of men and women in the same age bracket and from similar neighborhoods reported having sex an average of twice a week, he says.
More frequent sex -- more than three times a week -- didn't seem to produce any added benefits, Weeks says.
Casual sex doesn't count
And casual sex with different partners, or cheating, did not slow the aging process, the researchers say. In fact, Weeks says, it may cause premature aging from worry and stress.
"The sex doesn't work without a good relationship," Weeks says. "It works via a relationship that is very supportive and emphatic, in which both people are physically and emotionally compatible."
Others agree that sex can be good for your health.
"It's extremely important to your health," says Dr. Barbara Bartlik, a clinical professor of psychiatry at Weill Medical College of Cornell University in New York City. "It promotes marital harmony. The stresses and strains become more manageable when a couple is having sex regularly."
And Carol Ellison, a California psychologist and author of Generations of Women Share: Intimate Secrets of Sexual Self-Acceptance, says previous research has shown other physiological benefits to sex as well.
Sex can burn fat and cause the brain to release endorphins, naturally occurring chemicals that act as painkillers and reduce anxiety, she says. In men, sex seems to stimulate the release of growth hormones and testosterone, which strengthens bones and muscles. In both men and women, research has shown, sex also seems to prompt the release of substances that bolster the immune system.
And people who have lots of sex, Ellison says, tend to eat better and exercise more.
But three times a week may not be optimal for everyone, she says. People who are healthier and feel younger, for instance, may want more frequent sex.
Plus, she adds, sex means different things to different people.
To Weeks, sex and orgasms are one and the same. In his study, the researchers assumed that people who said they had sex three times a week also had orgasms three times a week.
"Sex is the most pleasurable activity people take part in, and because the orgasm is the most pleasurable of that, it's hard to separate it out," Weeks says. "It's hard to say if it accounts for 50 percent or 75 percent" of the beneficial effects.
Does sex = orgasm?
But Ellison believes good sex can take many forms.
"We're caught up in this idea that sex equals orgasm," Ellison says. "You don't have to put on a performance when you have sex. You don't even have to have intercourse."
Preoccupation with orgasm, especially among women, can make them feel like a failure in bed when it doesn't happen, she says.
"The key is not, 'How am I doing? Am I getting turned on fast enough? Is this going to happen?' " she says. "The key is, 'Am I enjoying what is happening at this moment?' "
How often those moments occur seems to depend on where in the world you live.
Americans had the most sex in 1999, according to a recent survey of 18,000 men and women between 16 and 25 years of age conducted by SSL International, the British manufacturer of Durex condoms.
The worldwide average was 96 times a year, but Americans claimed to have had sex 132 times a year, followed by the Russians (122), French (121) and Greeks (115). Young Japanese made love the least often (32 times a year), the survey says.
Americans also seem to be getting a head start on people from other countries, reporting the earliest average age at which they started having sex. Americans lost their virginity at an average age of 16.4 years, followed by Brazilians at age 16.5 and the French at 16.8, the survey says.
The French had the most sexual partners, claiming an average of 16.7 each. Greeks were second with 15 partners each, followed by Brazilians with 12.5 and Americans with 11.8. Residents of India were the most faithful to their partners, with 82 percent saying they had sex with just one person.
But Bartlik says it's best to take the survey with a grain of salt. Researching sexual behavior is difficult, she says, because it's hard to get truthful answers. Some people inflate their answers on purpose, and for many questions it's difficult to give precise responses unless you've kept a weekly chart of sexual activity, she says.
"Perception is everything," Bartlik says. "Just look at the Woody Allen movie [Annie Hall]. He says, 'We never have sex.' She says, 'We're having sex all the time.' "