A new study reveals that regular exercise improves your heart’s ability to beat.

RODALE NEWS, EMMAUS, PA—We all know that exercise is good for the heart, but scientists have never fully understood exactly why.

One theory, tested in a new study published in the American Journal of Public Health, is that exercise improves autonomic regulation of the heart, that is, your nervous system’s ability to make your heart beat. In healthy people, “there is good evidence that people who have higher levels of autonomic regulation of their hearts have reduced risks of developing heart disease and having adverse cardiac events,” says Richard P. Sloan, PhD, lead author of the study and professor of behavioral medicine at Columbia University Medical Center. In people who already have heart disease, he says, improving autonomic heart regulation can help cut their risks of recurring heart problems, primarily because improved heart regulation helps the heart get back into sync after a traumatic event.

THE DETAILS: Researchers recruited 149 young adults between the ages of 18 and 45 who didn’t exercise regularly but were in generally good health, and broke them up into two groups—an aerobic-conditioning group that exercised on stationary bikes, treadmills, and stair climbers and a strength-training group that focused more on push-ups, bench presses and other weight-lifting activities. The participants, 58 men and 91 women, went through a 3-month training program, during which they exercised 3 to 4 times a week, followed by a month-long “deconditioning,” during which they didn’t exercise at all. Their heart rates were monitored during both periods. Aerobic exercise appeared to be better at regulating the heart rate than strength training, however, that effect was seen only in men. That’s not to say women don’t benefit from exercise, says Sloan. “Women had the same improvements in aerobic capacity and became as well conditioned as men,” he says. Sloan and his colleagues hope to do follow-up research to determine why they didn’t observe improved heart regulation in the women.

WHAT IT MEANS: Elevating your heart rate to at least 70 percent of the maximum can go a long way to improving not only your overall health, but also your heart’s ability to recover after heart attacks or other cardiac events. While most of us know that exercise is good for us, it can be challenging to find time to stay fit. Here are some strategies that anyone can follow to get more exercise and keep a healthy heart:

• Do what you love. All aerobic fitness exercises will improve your heart health. Whether it’s swimming, running, or biking, find one you enjoy so you’ll be more inclined to stick with it.

• Think outside the box. If exercise classes and formal workouts aren’t your thing, find a hobby that combines leisure time with being active, such as dance classes, kickboxing, hiking, mountain biking, or active sports like soccer or basketball. Mix up different activities so you don’t feel stuck in a rut.

• Gradually increase your exercise intervals. Start out with realistic exercise goals that you can stick with. Participants in the study, who weren’t used to exercise, started out with 20-minute sessions 3 to 4 times a week. They gradually raised that to 45 minutes and, later, 60 minutes. Get to that 60-minute level eventually, and you’ll get a bonus: A University of Victoria study found that people who exercised for 60 minutes burned almost 5 times more calories after the workout than those who exercised for only 30 minutes.

• Walk this way for an extra calorie burn. Walking is a low-impact exercise that’s easy on your knees. Add to the calorie burn by bending your arms 90 degrees and pumping them as you walk. You’ll burn up to 15 percent more calories while you exercise.