Skip this important habit—23% of people do—and you‘re worse off than if you were a chronic smoker, or had heart disease or diabetes.

In fact, we’ve seen before that a certain type of exercise can make your body act like it’s nine years younger.

But a brand new study out of the Cleveland Clinic reveals that pure workaholics–many of whom are the type of people who never find the time to exercise–are creating worse conditions for themselves than some of the worst health habits and most common fatal conditions known to humankind.

About three times as bad as smoking in some cases, according to the study.

“Being unfit on a treadmill or in an exercise stress test has a worse prognosis, as far as death, than being hypertensive, being diabetic or being a current smoker,” Dr. Wael Jaber, the study’s senior author, told CNN. “We’ve never seen something as pronounced as this and as objective as this.”

Whoa.

Of course, there are other things that can lead people to skip the exercise habit. Heck, data from the Centers for Disease Control separately says only 23 percent of Americans get enough exercise.

But I know from personal experience that skipping fitness can be one of the easiest things to cut as an entrepreneur or an aspiring entrepreneur.

Especially if you’re an entrepreneur with other responsibilities, like raising a family or working a day job.

Its sort of like my colleague Jessica Stillman puts it: If you have five priorities in life–work, sleep, family, fitness, friends-you get to pick three. So let’s break this down.

1. I wrote recently about how crucial sleep is. So try not to skip it.
2. If you have a family, that’s crucial. Don’t skip on them either.
3. Friends? We’ve seen how important it is to develop relationships if you want to be happy and healthy. Heck, the longest-running study of its kind in this area hammers us over the head with that conclusion.
4. Work? That’s why this whole issue is extra acute for entrepreneurs.
5. Which leaves fitness. Exercise.

If there’s some good news to this study, it’s on the other side. If you get to the point where you’re an “ultra” exerciser, there’s no downside in terms of longevity, according to the study.

Maybe someday you’ll be at the point where you can make that a priority.

In the meantime, if you insist on being a workaholic–again, I know, I’ve been there–maybe there’s only one solution.

Buckle down. Power through. Make your fortune. And they know when to quit.

You can sleep when you’re dead, they say. But if you want to push that day further away, find time to exercise more now–or at least as soon as you can.