For Men: Super Sperm
In men, brief periods of sexual restraint seem to increase both the volume and the potency of semen. In a Swedish study, semen samples taken from a group of healthy men after one day of sexual abstinence and then later, after three days of abstinence, showed that when the men refrained from sex, the total volume of their ejaculate increased, as did the concentration of sperm. In fact, after three days, their total sperm count more than doubled.

Generally, guidelines for sperm donors and couples being evaluated for the treatment of infertility are to have the man refrain from ejaculation for three to six days before giving a specimen or having a sperm count done, in order to optimize the sperm count.

For Women: Vaginal
Atrophy But prolonged sexual abstinence, especially in women, may result in genital changes that make it a little more difficult to resume a satisfYing sex life later on.

Older women who lose their husbands, for instance, often notice that their vaginas gradually grow drier and less elastic. In older women who are sexually abstinent for many years, the vagina even may gradually begin to close up and "undergo such severe atrophy that intercourse becomes virtually impossible," says Gloria A. Bachmann, M.D., associate professor of obstetrics and gynecology at Robert Wood Johnson Medical School in New Providence, New Jersey.

On the other hand, the best way for older women to stay "genitally healthy" is to stay sexually active. Sometimes, obviously, that may not be a realistic option. But studies have shown that "women who continue to be sexually active, either with a partner or through self-stimulation, maintain a more nearly normal state of genital health than abstinent women," Dr. Bachmann says.

In one study of 59 women aged 60 to 70, for instance, those who remained sexually active had significantly less vaginal atrophy and greater vaginal elasticity, depth and lubrication than those who had closed the book on their sexual lives. In sex, as in many other areas of human physiology, the old, crude adage applies:
"U se it or lose it."