An old Korean proverb says that if you kick a stone in anger, you’ll hurt your own foot. A new study suggests there’s even more to the saying… the angrier you are, the more slowly your foot will heal.

Researchers at The Ohio State University discovered the connection between anger and healing by creating small blisters on the forearms of about one-hundred volunteers and monitoring how quickly the injuries healed. In the meantime, they studied how the volunteers expressed their anger. Did they keep their feelings to themselves? Did they express their anger in a productive way? Or did they lose self-control and lash out at others?

In the end, the researchers found that people who frequently lost control of their tempers were more likely to have blisters for more than four days after the injury. Their calmer counterparts healed much sooner. The study appeared in the journal Brain, Behavior and Immunity.

Previous research has discovered that angry patients heal more slowly after surgery, stay longer in the hospital and encounter more complications than other patients. Scientists say the stress hormone, cortisol, could explain why. In the Ohio study, people with lower self-control had higher cortisol levels and took longer to heal.

If you have a perpetually short fuse, try taking a step back and calming down before dealing with a frustrating situation. If simple exercises don’t work, anger-management counseling might be worth a try. Soothing what ails may mean going beyond the bandage.