The biggest authentic smile—called a Duchenne smile—happens when we use our whole face, show our teeth and crinkle the muscles around our eyes. What a beautiful outward projection of our inner positive emotion! Smiling can cause positive changes in our bodies, too, and even a fake smile is worth something.

Smile fact:
There are 19 different types of smiles.

Some of the physical benefits that occur when we smile may be surprising, such as improved immune function. Smiling activates brain chemicals that carry messages to our nerve cells and hormones called endorphins, which help us manage stress and make us feel good. When we smile, the nerve cells in our brain (brain neurons) activate in a pattern consistent with a happy mood. A smile can help us stay calm, reduce pain, boost our mood and lower our heart rate and blood pressure.

“What if I don’t feel like smiling?” you might ask. Well, brain scans show that even forcing a smile—researchers tested this by having a person hold a pen between their teeth to mimic the shape of a smile—was enough to activate key brain regions involved in positive emotion. When we “grin and bear it” or smile through stress, we can reduce our bodies’ stress response by slowing our heart rate, lowering our perception of stress and recovering more quickly from the stressful event.

Smile fact:
Children are champions when it comes to smiling. They smile 20 times more often than the typical adult.

Have you even been moved to smile when you see another person smiling at you? As part of what makes us social beings, our brain neurons activate in a similar way when we see another person smile just as they do when we smile. When we put on a happy face, we’re also more likely to see happiness in the faces of others—even when they have a “neutral” face on. We also interpret things to be more humorous when we’re wearing a smile. Our own smile activates brain regions that influence how we perceive those around us, and we end up seeing them in a more favorable way. Like Louis Armstrong said, “When You’re Smiling (The Whole World Smiles with You).”

Please share a smile for yourself and others! And remember that even “faking it until you make it” can give you a boost.

Erica A. Wehrwein, PhD, is an associate professor of physiology at Michigan State University.  Her research interests are on the connection between breathing and the nervous system, interactions of mindset and personality on physiological health outcomes and neural control of blood pressure.