It's a health problem of sorts, but you probably don't want to talk about it. Still, you--and millions of other people like you--can't help but wonder: how come I don't have more sex? Researchers agree the likely answer is not "because I'm sleeping too much instead." Like other fields of human endeavor, lovemaking is best with a well-rested mind and body. By the same token, the things that interfere with sleep can also stifle the libido. "The common wisdom among therapists is that our sex drive dips along with the Dow," says author and psychologist Dr. Judy Kuriansky. (That is not, however, the origin of the phrase "bull market.") "The libido is very sensitive to one's emotional state." Stress and anxiety, over the stock market or anything else, are nature's antiaphrodisiac; a recent survey by the Kinsey Institute found that 80 percent of men between 30 and 40 are sometimes too anxious to copulate, or even to think about it much. Unfortunately, the antidepressants that treat the anxiety may have the side effect of depressing the sex drive. Twelve-hour days at the office or night work at the plant are the enemies of connubial bliss; many a marriage has been buried on the graveyard shift. "To have a successful sex life, couples have to make time for sexual intimacy," says sex researcher Pepper Schwartz. And find that time without taking it away from the other important activity that takes place in bed.