Work out harder, not longer, to boost heart health by Cassie Shortsleeve, Men's Health Faster footsteps equal a healthier heart. Working out harder instead of longer could be the secret to warding off metabolic syndrome (MS), a combination of risk factors - which include obesity and high blood pressure - that increase your risk for cardiovascular disease, according to new research in the BMJ Open. Ten years after gathering people's baseline fitness habits - including workout length and intensity - researchers found that those who reported jogging or brisk walking 2 to 4 hours a week cut their risk of developing MS by 35 to 50 percent. About 19 percent of inactive people developed MS, compared to just 12 percent of very active people. The cardiovascular impact of high-intensity exercise versus light exercise has been a longstanding debate, says cardiologist Eric Topol, M.D., director of the Scripps Translational Science Institute and a Men's Health expert advisor. While the jury remains out, the new study lends credence to the high-intensity camp. "Higher-intensity exercise does have a whole different impact on the body's physiology," says Dr. Topol. Everything is more pronounced: your heart rate is higher, your blood vessels are more dilated, and you're revving up your cardiovascular system as you would a car, Dr. Topol adds. The results of this study fall in line with past studies on the topic: There's some kind of a threshold that you need to surpass in order to see changes. And it's possible that intense exercise triggers those changes in lipid and glucose metabolism and blood pressure, lowering the risk factors that trigger MS, says David Maron, M.D., a cardiologist at Vanderbilt University's medical center. Discover tons of ways to keep your heart pumping strong with The Lean Belly Prescription, your no-diet, no-workout plan that's better than running 5 miles a day! But don't give up your leisurely evening walks just yet. A recent study in Circulation found that just 2.5 hours of light exercise a week can reduce inflammation in your body thought to be a major contributing factor for developing heart disease. The key: Make sure your heart rate hovers around 120 beats per minute (think: not quite heavy breathing, but breathing more heavily than normal), and that you put in the recommended 2.5 hours for the week. So what's the happy medium? Be your own judge. While the BMJ Open study found that light physical activity didn't decrease the participants" MS risk - even if they walked for 2 hours a week - brisk walking was categorized as high intensity. If going hard for you means brisk walking, do that until it becomes easy, then take it up a notch. "Rigorous aerobic activity is really the best," Topol says. So, if you enjoy your nightly stroll, just make sure you're sweating it out in the morning, too. (Looking for a great routine? Try one of these 3 New Killer Cardio Workouts!)