In the face of a black eye, a sprained ankle or a bruised knee, most people turn to the icebox first. However, new research has revealed that cooling may in fact slow down the healing process.

The mechanism behind this lies in the body’s hormones. Icing an injury could prevent the release of a certain hormone that is integral to the repair process.

Inflamed cells produce high levels of an insulin-like hormone—aptly named insulin-like growth factor-1 (IGF-1)—which dramatically increases the rate of muscle regeneration.

In a study using mice, scientists discovered that those that were unable to form an inflammatory response to injury simply did not heal when they experienced muscle injury.

This finding has consequences for therapies for acute muscle injuries that are caused by trauma, chemicals, infections, freeze damage and exposure to medications.

Lan Zhou, one of the researchers from the Neuroinflammation Research Centre at the Cleveland Clinic in Ohio, reported: “We hope that our findings stimulate further research to dissect different roles played by tissue inflammation in clinical settings, so we can utilise the positive effects and control the negative effects of tissue inflammation.”

This discovery may also alter the amount of patient monitoring required when anti-inflammatory drugs are prescribed over the long term.