Here’s a thought to take to heart: it turns out that true forgiveness is great for both body and soul. Letting go can lower blood pressure, improve sleep and increase life span, according to recent medical research reported in GOOD.

Kathleen Lawler-Row is head of psychology at East Carolina University, and one of a growing number of researchers to explore the impact of forgiveness:

In a 2005 study, she found that sleep quality – which has a known effect on various bodily systems – was positively correlated with forgiveness and negatively correlated with the motivation for revenge. In other words, forgiving someone will make you sleep better at night, but holding on to resentment is likely to lead to insomnia.

In an earlier study, Lawler compared physiological responses to different types of forgiveness, looking at what she describes as "forgiveness as a trait," as well as forgiveness as a reaction to a particular event. In that study, groups of participants were asked to recount experiences in which they had been betrayed; each participant told two stories, one about a friend or partner and the other about a parent. After each story, Lawler gave participants a "recovery" time, during which they were kept silent in a darkened room, listening to soothing music and viewing peaceful images. She recorded what was happening with their blood pressure and heart rates during all of these periods of time and her results were conclusive. "Forgiveness is aptly described as 'a change of heart,'" she writes.

Learn more: Lawler isn’t the only researcher to confirm that forgiveness is good for your health. Check out the work of two university teams in New York and Virginia on its rewards.

And let us know what you think: it always healthy to forgive and forget? Who should – or shouldn't – be forgiven and why? And what is hard to get over?