Sometimes it’s just one of those days–the traffic was terrible, your meeting went poorly, your new client is proving insane, even your hair isn’t looking its best. Changing your mood is easier than you think…

When the world is piling on reasons for grumpiness, it can feel like the only thing to do is crawl into bed and hope for better luck tomorrow. But according to a huge new study, getting out of your funk may be way easier that you realize.

It’s as simple as standing up.

For the study, researchers at Cambridge University and the University of Essex used a smartphone app to gather real-time information on the moods and activities of more than 10,000 participants. When they boiled down this massive data set, they came to a simple conclusion: If you want to be happier instantly, just stand up and move around.

“Our data show that happy people are more active in general,” said Cambridge’s Jason Rentfrow, the paper’s lead author. “However, our analyses also indicated that periods of physical activity led to increased positive mood, regardless of individuals’ baseline happiness.” In short, it’s not just that active people also happen to be happier. Physical activity actually makes your happy. And it doesn’t take much.

“What we’ve found is that in order to be happier, you don’t have to go out and run a marathon–all you’ve really got to do is periodically engage in slight physical activity throughout the day,” Rentfrow goes on to say.

The unbelievable (but research-backed) benefits of just a bit of activity.

It’s a compelling result, and one that adds to a long list of previous studies showing that simply bringing a bit more movement into your day can have outsized benefits, not just on your mood, but on your health, thinking, and maybe even creativity.

For instance, previous research shows that short, periodic strolls are enough to counteract the truly horrible health effects of sitting all day, while another study found simply standing up boosts your brainpower by 7 percent. Yet another recent finding linked physical movements, like pacing and gesturing, with creativity in kids. And some kinds of fun and not-too-strenuous activity (like climbing a tree) have even been shown to boost memory.

So I ask you: When’s the last time you stood up and took a walk around? Maybe you should do that now.