How imperative is being fit to living a longer and healthier life? Much more than we might have ever realized. In fact, a new report finds that not being fit is seen to be as dangerous to our health as smoking.

We can put it in a more positive light: By being fit, you reduce your risk of dying early in just about the same way that not smoking keeps you alive longer. Either way, if we don’t do something soon, we’re in trouble. Close to one-third of Americans are considered obese. Only 20 percent get the recommended amount of exercise.

To come to these conclusions, writes Gretchen Reynolds in a New York Times story, researchers used a database of middle-aged men and women who had completed treadmill tests, and pulled records of more than 122,000 of them. They then checked death records for 10 years after those tests were administered.

The results? “Some of the men and women had died and also there are strong correlations between fitness and mortality,” Reynolds writes. “The greater someone’s fitness, the less likely he or she was to have died prematurely and vice versa, the numbers showed.”

Those in the study with the lowest fitness level, she continues, were more likely to die early than those whose level was considered below average. Those with above-average fitness were more likely to die before those with high fitness levels.

The study used the phrase “being fit” over “exercise,” and did not offer any specific amount of exercise needed to be fit. Which means you just have to move. You don’t have to run a marathon or swim 100 laps or do the elliptical machine for an hour. Walk at lunch. Take the stairs. Run in place during commercials. Do countertop push-ups while your coffee reheats.

The American Heart Association recommends adults spend 150 minutes per week in moderate exercise, 75 in vigorous, or a combination of the two. Basically, that’s a half-hour a day. You can even spread that out over three 10-minute chunks. Can’t most of us manage that?

It doesn’t even need to be that long, according to Dr. Annie Ray, a family physician who wrote a post for the newsletter about four things doctors want patients to know. One involved exercise: Stop making excuses for not doing it, she writes.

“You can get an excellent workout in 12 minutes with high-intensity interval training, so I don’t want to hear, ‘I don’t have time.’ Just shoot straight, tell me where you are, and we’ll work from there.”

Still think it’s impossible? Here’s a five-minute workout from Men’s Health. Try to do it a few times a week and tell yourself, “In five minutes, you can either be finished or you can still be griping about getting started.”

Here’s how it works: Do one squat, then 10 pushups. Then do two squats and nine pushups. Keep adding one more squat and one fewer pushup until you’ve done 10 squats and one pushup. Grand total: 55 of each. If you haven’t hit the five-minute mark, add five of each until you do.

OK, I’m pushing you out the door now, or at least handing you a jump rope and some light weights. Go for it. And while you’re at it, if you happen to be a smoker, for your own sake and for the sake of us all, please try to at least cut down. We’re all in this fitness thing together.