Can your own brain put the brakes on the rollercoaster of ups and downs that leave you stressed and frazzled? Meditation won’t smooth away life’s bumps, but it can change your reaction to stressful situations.A six-week Ohio State University study of working adults who followed 20-minute guided meditation four times per week and participated in a weekly 60-minute stress-reduction class showed significant decreases in perceived stress, improved ability to attend to the present moment and better quality of sleep.And a USC study of medical students who practiced breathing from the diaphragm, relaxation and walking meditation, showed an almost 47 percent reduction in stress prevalence.Regular meditation practice can also make it harder for stress to accumulate. “With regular meditation, stress doesn’t usually build up as easily. That’s why it’s important to do it every day. You’re better off meditating a few minutes every day than an hour once a week,” says Deb Shapiro, meditation expert and co-author of “Be the Change.”How to start: Visualize yourself in a place you find relaxing, like a garden or beach. Breathe and allow yourself to be present there for a few minutes, mentally guiding yourself through the scene and noticing the colors and the details around you. Your mind will remain focused, but the source of your stress will clear away during your meditation. When you return from your visualization, continue to be mindful of your breath.Another effective meditation for stress relief is walking meditation, since the repeated movement allows the body to release physical tension, even as the mind releases stressful thoughts. Practice walking meditation by walking slowly and mindfully, concentrating on each step and breath. Clasp your hands gently in front of you and lower your eyes to avoid distraction.Try walking meditation on the street, in your backyard or in your living room. Be mindful of your breathing as a measure of your stress level throughout the day. When your breath moves to the upper part of your chest, return it slowly to the center or lower part of your torso to encourage calmness.