"Exercise is the only real fountain of youth that exists, It's like the oil-and-lube job for your car. You don't have to do it, but your car will definitely run better." Study after study has documented the benefits of exercise to improve mood, mental acuity, balance, muscle mass, and bone health. "And the benefits kick in immediately after your first workout. Don't worry if you're not a gym rat. Those who see the biggest payoffs are the ones who go from doing nothing to simply walking around the neighborhood or local mall for about 30 minutes a day. Building muscle with resistance training is also ideal, but yoga classes can give you similar strength-training effects if you're not into weight lifting.