How would you answer this question: “How many times have you felt mentally unwell in the past 30 days, for example, due to stress, depression, or emotional problems?”

Researchers from Yale and Oxford asked over 1.2 million Americans that exact same thing.

In order to examine the relationship between exercise and mood, they also inquired about income and physical activities. Leaving no stone unturned, researchers asked about all the ways a person can move– from doing housework to weight lifting.

Nobody is happy all the time, so they found that participants who exercised regularly felt mentally unwell 35 days of the year. That being said, participants who didn’t exercise felt bad for 18 whole days more, on average.

A little quick math: that’s 53 days of feeling mentally unwell a year! Seven and a half weeks! Almost two months! You get the idea.

The data also revealed that exercise affects mental health more than economic status. And it doesn’t matter what kind of exercise you do. All types of physical activity were associated with better mental health.

As the old adage says, money can’t buy happiness. Which is good news, because you don’t need to spend money on happiness, all you need to do is work out.