Sex before sports: Sexual intercourse before an athletic event. A commonly held belief in sports is that athletes should not have intercourse before performing, lest it weaken them. This belief was not always held. In 77 AD, Pliny the Elder wrote to the contrary that: "Athletes when sluggish are revitalized by lovemaking." In fact, sex does not impair an athlete's performance, as proved by treadmill tests before and after intercourse. And perhaps in keeping with Pliny's observation, lovemaking raises testosterone levels in men. Whether it truly revitalizes them is unproven.