We all know that.
But that doesn't mean you should hit the gym at 5am, sprint to and from work, and down a protein shake before your evening 100-press-ups routine.
But it turns out too much exercise is worse for your heart than not being active enough.
If you needed another excuse to ditch your morning run.
Researchers investigated the link between exercise and atherosclerosis - the fat buildup in arteries that can lead to more serious problems including heart attacks.
The length and size of the study is nothing to sniff at with 3,175 men and women observed over the course of 25 years.
The U.S. Department of Health's exercise guidelines recommend at least 2 hours and 30 minutes a week of moderate exercise or 1 hour and 15 minutes of strenuous aerobic workouts.
White men who exceed this by three times or more were, according to the study, at an increased risk of atherosclerosis by the time they hit middle-age.
Interestingly, the same did not appear to apply to black adults in the survey, a quirk that means more research is necessary.
Don't throw out your pricey active wear just yet.
The data also confirmed that people who didn't exercise enough were more likely to have type 2 diabetes and high blood pressure.
Cardiologist Dr. Joel Kahn told CBS News that mixing up your exercise routine can help with some of the stress that it puts on your body.
There is a stress reaction to long distance and long duration exercise—your cortisol is up for a long time.
It may be wise to build in daily stress reduction techniques, such as meditation, yoga—seven, eight hours of sleep.