Experts have long said that even short periods of exercise can boost heart health. Now there’s new proof. According to a study of postmenopausal women, just 10 minutes a day can help improve cardiovascular health. Quick stints "have a dual beneficial effect," says cardiologist Peter Diamond, MD, of the University of Illinois Medical Center. "They improve lean muscle mass, which helps the body burn more calories, and the aerobic activity promotes fat burning." Heart disease risk increases after 40, so this simple, effective, two-for-one workout is twice as smart now. Choose sequence A, B, or C. Workout Details Time it takes: 10 minutes. Set a timer for one minute, repeat the first move until the bell rings, then reset the timer and do the next move for a minute, and then the next. Continue until you’ve exercised for 10 minutes. If you have 20 minutes to spare, add a second sequence (see below). String all three together for a 30-minute, full-body workout. How often: Do at least one sequence every day. A few times a week, combine two or three sequences for a longer workout, or do two or three separate 10-minute sessions over the course of a day. To keep your heart rate up, rest for no more than 20 seconds between exercises. See results: You will feel stronger after one week, and notice tighter muscle tone in six weeks. Complementary workouts: Do at least 30 minutes of cardio exercise, such as walking or jumping rope, three to five times a week. Equipment needed: An egg timer, a towel, a pair of light dumbbells (3 to 5 pounds each; $12 to $17 per pair) and a fitness ball ($15 to $20). A soccer ball or basketball will also work. Additional sequences: "10-Minute Core Routine":http://www.more.com/preview/2027/3780-10-minute-toners-core-routine#1 "10-Minute Lower-Body Routine":http://www.more.com/preview/2027/3608-10-minute-toners-lower-body-routine#1 "Shop online for equipment":http://www.isokineticsinc.com/ Originally published in MORE magazine, December 2007/January 2008.