We all know that exercise is great for your physical health. But experts insist it's important for your mental health, too. Just how important? New research out of Yale and the University of Oxford puts exact numbers to just how much happier you'll be if you start a regular exercise routine. You'll be surprised at just how large they are. 

18 days and $25,000 

This wasn't just some small, preliminary study. The team crunched numbers on the habits of 1.2 million Americans, asking participants to both describe in detail their physical activity, including everything from lawn mowing to weight lifting, as well as to report how many days in the past month they felt mentally unwell due to stress, depression, or other reasons. 

The results were recently published in the prestigious journal The Lancet, and as Business Insider recently reported, the connection between regular workouts and better mental health was crystal clear. 

"The scientists found that while those who exercised regularly tended to feel bad for 35 days a year, nonactive participants felt bad for 18 days more, on average," writes BI's Ruqayyah Moynihan. "In addition, the researchers found that physically active people feel just as good as those who don't do sports but who earn about $25,000 more a year." 

No marathons or CrossFit required 

Just to underline that, you can buy yourself $25,000 worth of mental health and 18 additional happy days a year simply by regularly moving your body more.

And you don't have to be a CrossFit fanatic or marathon runner to see these impressive benefits. Finding some way to get your heart rate up for 30-60 minutes no more than five times a week was enough. Other studies back up the claim that modest amounts of exercise can have a big impact on your well-being

Remember that next time you tell yourself that running your business means you're too busy to squeeze in taking care of your body. 

Assumedly, you're working so hard to increase your sense of happiness and satisfaction. This new research suggests you might be able to get yourself further toward those goals by working a little less and working out a little more.