Everybody knows that smiling and laughing feels good, but now studies show that those grins and giggles may actually be helping you get or stay healthy.

According to Alternative Therapies in Health and Medicine, laughing decreases stress hormones in your body and releases natural cells that battle viruses and even cancer. According to the publication, watching a funny movie, giggling with a friend or attending a comedy act can help keep your immune system strong.

Laughter promotes feelings of well-being by reducing the amount of stress hormones such as epinephrine and cortisol in your body. And studies now also suggest that laughter increases the number and activity of so-called “killer T” cells that act as the body’s first defense against virus and damaged cells. So laugh it up!