Our bodies were made to be active, not to loll around all day in an easy chair, doze on the couch, or sit for hours staring at a blinking computer screen. Once upon a time, human beings were active out of necessity; we had to hunt for food and outrun our predators. But no more — and we’re actually worse for it.

My patients often ask me how much exercise they need to do to improve their heart health. Do they need to exercise at a gym, buy equipment to use at home, head for the ocean or pool? My answer is always the same: All you need to do is commit to walking one hour a day.

The reason that an hour is important is because of the way our bodies manage physical exercise. For the first half hour, you’re using a reserve of energy. Then, for that second half hour, your heart, your lungs, and your whole cardiovascular system has to kick into overdrive — and as a result, you’re strengthening your heart.

But if you haven’t been active before, simply start with 15 minutes a day and work up to more. You’ll be amazed by the results!