You probably know that a little exercise can do a lot for your mood. And if you read the AllPsych blog often, you know that simply telling people not to exercise for a week reliably lowers their life satisfaction.

Now, though, a pair of studies have shed some new light on the link between exercise and happiness and shown that the causation between exercise and happiness seems to flow in both directions. It turns out that whether people are in a good mood to begin with influences how likely they are to exercise and several different ways, and that people’s predictions of how they expect exercise to impact their mood also play a role.

The first study, published in Psychology & Health found that experiencing positive emotions like joy and hope makes people more likely to exercise in multiple ways. In particular, positive emotions in general seem to make people give higher priority to their exercise goals and increase their intentions to engage in physical activities. And joy in particular makes people willing to try a greater range of activities.

Of course, while being in a good mood seems to make people more likely to exercise, exercising also tends to raise people’s mood. So the second study, published in Health Psychology, looked at whether people’s anticipation of how exercise will impact their mood influences their intentions to exercise.

As you might expect, people have stronger intentions of exercising when they anticipate experiencing positive emotions from exercise – and when they remember experiencing positive emotions while exercising in the past. Interestingly, though, the study also found that people tend to underestimate how pleasant exercise will be and overestimate how fatiguing it’ll be. This result confirms the idea that the hardest part of exercising may be gathering the motivation to start.

Overall, the link between exercise and happiness appears to run in many directions. How happy people are to begin with influences their intentions to exercise, as do their expectations of whether exercise will make them happier. And of course, exercise itself tends to make people happier – perhaps by more than most people expect, it turns out.

Image: Flickr/MilitaryHealth