Holding a Grudge Produces Cortisol and Diminishes Oxytocin

We all know the physiological feeling created when your “blood is boiling” and you ruminate about ways to “get even” with someone who has hurt or betrayed you. Feelings of anger or revenge activate the “fight-or-flight” stress response of your sympathetic nervous system which causes cortisol levels to spike.

The stress response triggered by bitterness and rage also raises blood pressure, reduces the healthy tone of your vagus nerve, and activates a feedback loop of distress that can damage your health.

Are you currently holding a grudge against someone? Is someone holding a grudge against you? What was the transgression that led to the feelings of anger and resentment or a desire to seek revenge? Do you feel more like the perpetrator or the victim in this conflict? Are you in a position to apologize and make amends?

Having a vendetta or holding a grudge is toxic. Over the long run—if you don’t make conciliatory efforts to neutralize interpersonal conflicts—holding a grudge will wreak havoc inside your body. In many ways, holding a grudge is a form of self-sabotage. Luckily, you have the power to break this cycle.

A 2012 study by Dr. Michael McCullough and Benjamin Tabak found that the cortisol levels associated with interpersonal conflict decrease if a victim perceives that his or her transgressor is agreeable to making conciliatory gestures. Hopefully, this blog post will inspire anyone who is currently involved in a grudge to express your feelings, apologize, ask for forgiveness, and seek reconciliation.

The Yin-Yang of Oxytocin and Cortisol

On a basic level, harboring resentment and anger towards another person stimulates the stress response of the “fight-or-flight” mechanisms of the sympathetic nervous system which spikes levels of the “stress hormone” cortisol.

Conversely, resolving conflicts and letting go of your anger towards another person, stimulates the “tend-and-befriend” mechanisms of the parasympathetic nervous system which can increase human bonding and levels of the "love hormone" oxytocin.

In Chinese philosophy, yin-yang is described as, "how apparently opposite or contrary forces are actually complementary, interconnected, and interdependent in the natural world, and how they give rise to each other as they interrelate to one another." The yin-yang of the sympathetic and parasympathetic nervous system are like a gas pedal and a brake that work together within your body to maintain homeostasis and balance.

Ideally, the yin-yang of cortisol and oxytocin work together to create eustress, which is the "good stress" linked to passion and purpose; while reducing distress, which is the "bad stress" linked to disease.

If left unregulated, holding a grudge can create loneliness, isolation, and pent-up anger that creates an uptick in cortisol and lowers oxytocin. Recent studies have found that the attachment processes between two individuals in an intimate relationship dramatically affect physical and psychological health.

Dr. Paula Pietromonaco from the University of Massachusetts in Amherst does research on cognitive and affective processes in the context of close relationships. In a press release she said, "We know that having relationships in general and being socially integrated is associated with a reduced risk of mortality. Our research follows from attachment theory, which suggests that there is one primary person that people turn to for comfort when they are distressed or frightened."

"In adulthood, that person is often a romantic partner or spouse," she says. "These sorts of relationship partners are especially important when people are faced with a stressful event because they have the potential to comfort and calm the person who is experiencing distress or to hinder that person's efforts to feel better."

Pietromonaco and colleagues have found that the way in which people feel attached to one another affects cortisol levels in response to stress and can also be a way to predict depression or anxiety over time.

A March 2015 study from the University of Virginia (UVA) published in the jounal Frontiers in Human Neuroscience found that people with naturally higher levels of oxytocin showed greater brain activity when processing social information.

The researchers found that oxytocin is self-produced endogenously at different levels in different people and that this plays a role in regulating social behavior. Katie Lancaster, a Ph.D. candidate in psychology at UVA and first author explained this study in a press release,

The purpose of the study was to investigate how people's endogenous levels of oxytocin were related to brain activity when they viewed social interactions. We found that people with higher oxytocin levels showed greater recruitment of brain regions that support social cognition, suggesting that these people are naturally attending to the more social aspects of the interactions.

People with low levels of oxytocin showed less recruitment of these 'social brain' areas; their brain activity resembles the patterns of neural activity previously observed when people focus on non-socially relevant information.

The study could lead to better understanding of how oxytocin interacts with cognition in both healthy people and those who are more inclined to hold grudges than others. These findings beg the question if having lower self-produced levels of oxytocin might make someone less inclined to make conciliatory gestures, seek forgiveness or make amends.

Oxytocin and the Human Need to Bond Are Intertwined

As hunter-gatherers, early humans traveled in small bands and lived in groups. It's believed that group living preceded the emergence of living as a pair by about 35 million years. Researchers believe that oxytocin's role in one-on-one bonding probably evolved from an existing, broader affinity that homo sapiens had for group living.

Many studies have found that social isolation is detrimental for our well-being. One of the problems of modern living in a Facebook age is that many of us feel isolated because our social network exists in cyberspace which can cause oxytocin levels to plummet.

A March 2015 study led by Adrian Jaeggi from University of California, Santa Barbara found that levels of oxytocin increased among Tsimané men living in the Amazon when they come home to their families after a day of hunting. The researchers also found that the amount of oxytocin increased relative to how long a hunter had been away from home.

The increase of endogenous oxytocin has a correlation to pair-bonding, parenting, and social connectivity in humans and other species. Various studies on oxytocin have found that it is a way of quantifying the depth of interpersonal relationships.

"Oxytocin levels indicate how much you value another person," said Jaeggi in a press release. "It's like a physiological measure of the value of that relationship." According to Jaeggi, when you fall in love with someone your oxytocin level will skyrocket whenever your sweetheart feels close to you. "Even talking to someone on the phone is enough to cause that oxytocin increase," he said.

Expressing Your Anger Can Be an Integral Part of the Forgiveness Process

It's not always best to forgive and forget—especially if you're married. Sometimes expressing anger at your spouse might be necessary to resolve a relationship problem before it has time to fester and turn into a grudge. Sometimes, the short-term discomfort of an angry, but honest, conversation helps to avoid a breakdown of communication and rumination.

William Blake said famously, “I was angry with my friend: I told my wrath, my wrath did end. I was angry with my foe: I told it not, my wrath did grow.” It may seem counterintuitive, but sometimes expressing anger in an even-tempered way is an important first step towards forgiveness and reconciliation.

"We all experience a time in a relationship in which a partner transgresses against us in some way. For example, a partner may be financially irresponsible, unfaithful, or unsupportive," Dr. James McNulty from Florida University said in a press release about a lecture he gave at the APA annual convention recently. Adding, "When these events occur, we must decide whether we should be angry and hold onto that anger, or forgive."

McNulty's research shows that a variety of factors can complicate the effectiveness of forgiveness, including a partner's level of agreeableness and the severity and frequency of the transgression. "Believing a partner is forgiving leads agreeable people to be less likely to offend that partner and disagreeable people to be more likely to offend that partner," he says.

Additionally, he says, anger can serve an important role in signaling to a transgressing partner that the offensive behavior is not acceptable. McNulty concluded,

If the partner can do something to resolve a problem that is likely to otherwise continue and negatively affect the relationship, people may experience long-term benefits by temporarily withholding forgiveness and expressing anger.

This work suggests people need to be flexible in how they address the problems that will inevitably arise over the course of their relationships. There is no 'magic bullet,' no single way to think or behave in a relationship. The consequences of each decision we make in our relationships depends on the circumstances that surround that decision.

Bottling up your emotions or not expressing anger can be just as toxic as holding a grudge. Hopefully, animosity and hostility can ultimately be replaced with equanimity. The definition of equanimity is, “mental calmness, composure, and evenness of temper, especially in a difficult situation.” That said, repressing anger or other negative emotions in an attempt to constantly remain "even-keel” and maintain equanimity can sometimes backfire.

Conciliatory Gestures Promote Forgiveness and Well-Being

In one of the largest, longest and most definitive studies on the effects of conciliatory gestures and conflict resolution, researchers have confirmed what we all know from life experience—peacemaking efforts and owning up to one's responsibility in a transgression promotes forgiveness and reduces anger.

The 2014 study, “Conciliatory Gestures Promote Forgiveness and Reduce Anger in Humans,” was published in Proceedings of the National Academy of Sciences. Michael McCullough, principal investigator of the study, said in a press release,

All of the things that people are motivated to do when they have harmed someone they care about really do appear to be effective at helping victims forgive and get over their anger. People often think that evolution designed people to be mean, violent, and selfish, but humans need relationship partners, so natural selection probably also gave us tools to help us restore important relationships after they have been damaged by conflict.

One basic scientific implication of the results is that humans are wired for conflict resolution much like non-human animals who live in groups tend to restore valuable relationships.

McCullough concluded, "Many group-living vertebrates, but particularly mammals, seem to use 'conciliatory gestures' as signals of their desire to end conflict and restore cooperative relationships with other individuals after aggressive conflict has occurred. We seem to have a similar psychology as well."

Are You Holding a Grudge Against Yourself?

Forgiving ourselves can often be more difficult than forgiving someone else. Do you beat yourself up for past transgressions and the times that you’ve said or done something that you regret? If so, forgive yourself and let it go!

Holding a grudge against yourself and feeling shame can trigger the same increase in cortisol and decrease in oxytocin as holding a grudge against someone else. Self-forgiveness is just as important as forgiving others.

If you are holding a grudge against yourself, make amends with yourself and let the healing from these self-inflicted wounds begin. If you’d like to read more on how to do this, check out my Psychology Today blog post, “10 Keys to Happier Living Based on Self-Acceptance.”

Over the years, I’ve grown to appreciate the benefits of taking a few minutes every day to practice loving-kindness meditation (LKM). Loving-kindness meditation is a highly effective way to fortify compassion and forgiveness towards yourself and others.

You can do LKM anytime you have a few quiet minutes to close your eyes and systematically go through a 4-step process of directing loving, compassionate, and forgiving thoughts to four categories of people in this order: 1) Loved ones 2) Someone with whom there is a conflict or a grudge 3) Strangers 4) Yourself.

Conclusion: Resolving a Grudge Relies on Mutual Conciliatory Efforts

You can never force someone to forgive you. Everyone needs to move through the process of forgiveness at his of her own speed. That said, hopefully reading this blog post will inspire anyone who is holding a grudge to break the cycle and make conciliatory gestures sooner than later.

If you are truly sorry about something you've said or done, let the person know. Making conciliatory gestures and expressing your sincere sorrow or regret—while asking for forgiveness—is the best way to end a grudge.

If you'd like to read more on this topic, check out my previous Psychology Today posts:

• "Cortisol: Why "The Stress Hormone" Is Public Enemy No. 1"
• “The “Love Hormone” Drives Human Urge for Connection”
• “The Neurobiology of the “Love Hormone” Revealed”
• "Mindfulness: The Power of 'Thinking About Your Thinking'"
• "Neuroscientists Confirm That Our Loved Ones Become Ourselves"
• "Mindfulness Training and the Compassionate Brain"
• “Compassion Can Be Trained”
• “Simple Ways to Turn Negativity Into Self-Nourishment”
• “The Evolutionary Biology of Altruism”
• "Optimism Stabilizes Cortisol and Lowers Stress"
• “The Neuroscience of Social Pain”
• “Maintaining Healthy Social Connections Improves Well-Being"
• "4 Simple Ways to Replace Hostility With Equanimity”
• "The Neurobiology of Grace Under Pressure"

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