Amid so much exuberant hype about spa treatments, green tea, and the "science of happiness," many of us have forgotten a paramount law of human behavior: Stress makes us great. "Stress inspires performance and efficiency," says Herbert Benson, a professor at Harvard Medical School and founder of the Mind/Body Institute, in Chestnut Hill, Massachusetts. "But"—and here's the catch—"only to a point." Benson has studied that point for the past 36 years in a bid to understand the dynamics that underlie human stress, relaxation, and aptitude. What he's found is that by pushing ourselves to the brink of a freakout, then retreating to a calming activity, we can induce a transformative relaxation response that propels us to the height of our capabilities. When stress sets in as we begin a challenging endeavor, hormonal releases lead to improved focus and creativity. Push too hard for too long, however, and you'll pass a critical juncture and go from feeling motivated and alert to anxious and incapable. But stop just short of the crash and turn to a mellowing activity—exercise, artwork, whatever works for you—and you'll kick off a biochemical reaction that delivers a momentary buzz and new insights, followed by a period of lasting superior performance. "You want to get as close as possible to peak stress levels," says Benson, who details the strategy in The Breakout Principle (Scribner). "With enough trial and error, you'll learn where that place is." And the spas and green tea? Can't hurt.

Bringing Sex Back
While the biological benefits of sexual activity have long been recognized by scientists, there's been little public discussion about an intriguing finding from recent research: When it comes to reducing stress, good ol' intercourse is best. In 2006, Stuart Brody, a professor of psychology at the UK's University of Paisley, published a study in which male and female subjects recorded their sex acts for two weeks in a diary, then submitted to a stress test that had them deliver a speech before a panel. Blood-pressure measurements convincingly demonstrated that subjects who'd engaged only in intercourse had the lowest stress levels, followed by those who'd had intercourse and also engaged in other sex acts, then by those who'd only engaged in other sex acts, then by those who only self-pleasured, and finally by those who didn't get any at all. Brody points to a number of chemical, physical, and social factors that may play into the process, but the takeaway is there: To reduce stress, do it the old-fashioned way—with no solo action or extracurricular activities.