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Talking about difficult experiences can be a way of easing the emotional pain of trauma, but the latest research shows that expressing emotions in words can also speed physical healing.

The study is the latest delving into the mind-body connection to suggest that expressing emotions about a traumatic experience in a coherent way may be important to not just mental but physical health as well. It showed that the calming effect of writing can cut physical wound healing time nearly in half.

Researchers led by Elizabeth Broadbent, a senior lecturer in health psychology at the University of Auckland in New Zealand, studied 49 healthy senior citizens, aged 64 to 97. For three days, half were assigned to write for 20 minutes a day about the most traumatic event they had experienced, and were encouraged to be as open and candid as they could about exactly what they felt and thought at the time. If possible, they were also asked to share thoughts or emotions that they had never expressed to others about what they had undergone.

The other participants wrote for the same duration about their plans for the next day, avoiding mentioning their feelings, opinions or beliefs. Two weeks after the first day of writing, researchers took small skin biopsies, under local anesthesia, that left a wound on the arms of all participants. The skin tissue was used for another study.

A week later, Broadbent and her colleagues started photographing the wounds every three to five days until they were completely healed. Eleven days after the biopsy, 76% of the group that had written about trauma had fully healed while only 42% of the other group had.

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“This is the first study to show that writing about personally distressing events can speed wound healing in [an older] population that is at risk of poor healing,” says Broadbent.

It’s not the first, however, to reveal the intriguing connection between state-of-mind and physical health. In previous studies, this type of emotionally expressive writing, as opposed to writing on neutral topics, reduced viral load in HIV-positive patients and increased their levels of virus-fighting immune cells. The practice also increased the effectiveness of the hepatitis B vaccination by increasing antibody levels generated by the vaccine and speeding wound healing in young men.

But in terms of psychological health, the results are more conflicting. A recent study found that writing about disturbing combat experiences may improve marital satisfaction among soldiers returning home from war zones while another paper in which patients with post-traumatic stress disorder (PTSD) wrote about their difficult experiences did not find that the practice reduced symptoms. Putting emotions down in words did, however, improve mood and reduce levels of stress hormone in these patients.

One way that writing about distressing events could give the body a boost is by promoting sleep. “We found that people who got at least seven hours of sleep most nights had faster healing than those who got less sleep,” Broadbent says. Sleep deprivation can lower levels of growth hormone, which is important for repairing injuries. And writing about their traumatic experiences also seemed to help participants to actually get more sleep. “Many people who have written about their negative experiences report that it allowed them to gain greater insight into what happened and to put the event into perspective,” says Koschwanez, “This might reduce the extent to which the event troubles them and possibly improve their sleep.”

The writing may also help the body by reducing stress; less anxiety means fewer stress hormones, which can interfere with chemicals needed for wound healing. While Broadbent’s study did not find such a link, it’s possible the researchers were not evaluating the right anxiety measures. “It might be that our perceived stress questionnaire was not assessing the right type or duration of stress,” says Heidi Koschwanez, a study co-author and postdoctoral fellow at the University of Auckland.

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It’s also possible that emotional writing is not helpful for everyone. In one study published last month, when people who typically are stoic wrote about their worst trauma, their anxiety actually increased. Those who were accustomed to being emotionally open, however, showed a drop in worry measures. That suggests that different people may have different ways of coping with traumatic events, and that writing may be an effective outlet for those who are normally more expressive, while pushing people to express feelings when they are not inclined to do so can actually increase risk for PTSD.

For those who do experience relief from expressing their emotions, however, writing may become an important part of helping them to recover —both in mind and in body— from difficult situations.