Mental imagery might help you “find a happy place” in more ways than one: it can actually hasten recovery from surgery, according to two recent studies.

In the first study, people who had undergone surgery to repair the anterior cruciate ligament of the knee (ACL) were randomly assigned to one of two groups. All participants received standard rehabilitation during the six months after surgery, but one group also practiced guided imagery while recovering. The imagery, which was conducted in sessions with a therapist and recorded for later listening, included mentally rehearsing physical therapy exercises and visualizing the physiological healing process specific to ACL surgery, such as scar tissue becoming flexible with gentle stretching. According to the results published in the December 2012 issue of the Scandinavian Journal of Medicine and Science in Sports, the group that practiced imagery showed greater improvements in knee stability and reduced levels of stress hormones. The study authors speculate that imagery may speed recovery by reducing stress, which has been shown to interfere with healing.

The other experiment focused on patients scheduled for gallbladder removal and was published in the February 2012 issue of Brain, Behavior, and Immunity. The patients were randomly assigned to either a group receiving only standard care or to one that also involved relaxation and guided imagery for three days before and seven days after surgery. “We used a relaxation intervention to try to reduce stress and therefore get a better inflammatory response to surgery and improve healing,” says Elizabeth Broadbent, professor of medicine at the University of Auckland in New Zealand and co-author of the study. The first set of imagery exercises focused on being relaxed and ready for surgery, whereas the postsurgery imagery concentrated on the body's healing process. For example, participants imagined oxygen and nutrients traveling to the surgical wound and helping the body knit the skin back together, easing discomfort and bringing soothing relief.

Compared with the control group, participants who practiced imagery reported a larger reduction in stress, and their wounds showed signs of greater collagen deposition and faster healing. Although it is not possible to determine how much the effects result from the imagery versus simply being relaxed, Broadbent says both factors probably worked together and that the imagery most likely enhanced the stress-reducing effects of the relaxation.