The BenefitsIt’s so unfair: Just at the age when you start figuring things out — who you are, what you want out of life — you begin noticing that you’re losing your mind. Already, at 44, I not only forget where I left my keys, I get in the car and have no idea where I’m going. I’m worried that what’s left of my poor brain is starting to petrify. Finally sure of my priorities and values, I’m cross with others who don’t see things my way. I’m anxious about getting older, and impatient with my little aches and pains. When I look in the mirror, I see not just superficial wrinkles, but something deeper and more troublesome — the nascent beginnings of a forgetful, cranky, inflexible old bat.Forget about anti-aging creams. I need something to reset my mental clock.Is there anything like exercise for the brain to keep it in shape? Studies have shown that doing crossword puzzles helps keep the mind sharp, but I doubt that struggling with 37-down, "Palenque king," can relieve the stress, anxieties, and mental rigidity that can accompany aging. Recently, alarmed at my brain’s seemingly swift degeneration (not to mention my impatience, distractedness, and maddening forgetfulness), I decided to try a different kind of mental exercise: meditation. It seemed unlikely that simply sitting, closing my eyes, and focusing on my breathing could help. But after only a couple of weeks — results are quick — I was starting to believe that the best thing to keep my mind calm, cheerful, flexible, and focused is to do nothing, for 15 minutes a day. Meditation made me feel both relaxed and more energetic. I developed a bit of distance between events and my reactions. Someone cut me off in the car? Maybe he’s having a bad day. A promising date didn’t blossom into a romance? Perhaps it’s his problem, not mine. Even at this early stage, I’ve noticed I’m much more able to let go of judgments of myself and others. I wondered: Can meditation really keep your mind young? And if your mind stays young, will your body follow?When I attended a daylong meditation retreat to strengthen my practice, it certainly appeared that way. The participants, mostly a decade older than I, radiated the kind of clear-eyed luminosity one associates with the bloom of youth. "I don’t know whether meditation actually makes you younger," said the teacher, who, in his 60s, had no trouble sitting cross-legged for hours on end. "But it sure as hell makes you feel younger."It turns out that how you feel — stressed or relaxed, anxious or calm — does affect the aging process. Recent research suggests that meditation and other forms of mindful relaxation may help slow down the biological clock, so you’re better able to heal and to withstand disease. "There’s a reason why experienced meditators live so long and look so young," says Eva Selhub, MD, medical director of the Mind/Body Medical Institute. That reason has mainly to do with reducing stress. Though there is little direct research on meditation and aging, one 1989 study of residents in nursing homes showed that those who practiced transcendental meditation had better mental flexibility and lower blood pressure, and lived longer.Stress = AgingWhy? Researchers suspect that meditation slows down aging because aging is, in many ways, an accumulation of stress. The new thinking is that our cells, under stress, may stop regenerating as quickly, and become more prone to disease and early cell death. Meditation and other forms of deliberate relaxation also change the way you perceive stress, which actually lightens the physiological load. To some extent, age really is a state of mind: If you feel young, you’re apt to be physiologically younger and healthier than your cranky peers."If we can affect the stress response, we can affect the aging process," says Selhub. The longer we live, the more stress we’re under, because stressful events are stored in our brains, Selhub continues, like icons on a computer, and each new anxiety triggers a lifetime’s worth of anxiety, like double-clicking on that icon. The average woman over 40, who deals with work, kids, relationships, and her changing life and body, has about 50 of these stress responses a day.