It’s been said that we are the average of the five people we spend the most time with. If that saying is true, then we might want to choose people who are physically active to be in our circles. In a new study published in the journal PLOS ONE, researchers created a mathematical model to learn the influence of social interactions on community exercise patterns. Their model showed that without social interactions, populations experienced a long-term decrease in physically active individuals, and most people exhibited sedentary lifestyles. But when the model had sedentary people interacting frequently with people who were active, they became more active themselves over time. In other words, if you want to exercise more, spend more time with people who like to exercise.