Part Two of a series on the psychological and existential dimensions of health. Part One: Beliefs, Faith & Spirituality. Coming: Life Purpose & Existential Angst · Past, Present & Future · The Autonomic Balance.
I have sat with a lot of people over thirty-seven years who were carrying something they had decided they were entitled to carry.
A parent who chose a sibling. A partner who left without explanation. A colleague who took credit, a friend who disappeared when things got hard, an institution that failed them at a moment when it mattered. An employer. A doctor. Sometimes a whole system.
The grievance was real. The harm was real. I am not going to tell you it wasn’t. The thing I want to examine is what happens to the body while you carry it — and whether the carrying is serving you in the way you think it is.
Because the clinical evidence on this is more definitive than most people realise, and it points in a direction that a lot of people don’t want to go. Not because they don’t understand it. Because going there feels like letting someone off the hook. And that, it turns out, is the central misunderstanding.
What a grudge actually is, physiologically
When you rehearse a grievance — replay the event, reconstruct the injustice, feel again the anger or the hurt or the contempt — your HPA axis responds as if the event is happening now. Cortisol rises. Sympathetic tone increases. Inflammatory cytokines shift. The body prepares for a threat that exists only in the reconstruction.
This is the same mechanism I described in the post on present-moment awareness — the brain does not reliably distinguish between a memory and a current threat. What it responds to is the vividness and emotional charge of the mental content, not its temporal location. A grudge, rehearsed regularly, is a regular stress activation. A long-held grudge, rehearsed over years, is years of repeated stress activations built around content that does not change and does not resolve.
The HPA axis adapts to chronic stimulation. Initially cortisol rises with each activation. Over time, in the pattern of chronic unresolved stress, the axis begins to down-regulate — receptors become less sensitive, the feedback loop becomes less efficient, the diurnal curve flattens. The person moves from a state of hyperactivation to a state of blunted response — exhausted rather than wired, flat rather than anxious, depleted rather than reactive.
Both states have clinical consequences. But the flattened, depleted pattern — the one that shows up as low morning cortisol, poor stress resilience, fatigue that doesn’t resolve with rest — is particularly hard to shift while the source of chronic activation remains in place.
Witvliet et al. (2001, Psychological Science) had participants imagine forgiving versus holding grudges against someone who had wronged them, while physiological measures were taken. Unforgiving responses produced significantly greater sympathetic arousal, higher heart rate, higher blood pressure, and more negative affect than forgiving imagery — effects that were immediate, measurable, and consistent across participants regardless of the nature of the original harm.
Lawler et al. (2005) found that trait forgiveness was associated with lower resting blood pressure, lower heart rate, and better heart rate variability — markers of better autonomic regulation — independent of personality variables, health behaviours, and social support. The effect was not trivial: it was comparable in magnitude to the cardiovascular benefits of regular moderate exercise.
Chronic resentment is, in physiological terms, a self-administered stress protocol. The person who wronged you may have moved on entirely. You are running the cortisol activation on their behalf, at your expense, on a loop that serves neither of you.
The misrepresentation of forgiveness
Forgiveness has been so thoroughly co-opted by a particular brand of spiritual and therapeutic optimism that the word itself has become a barrier. People hear it and think: condoning what happened. Pretending it didn’t matter. Reconciling with someone who hasn’t changed. Performing magnanimity for the benefit of an audience. Being the bigger person in a way that requires swallowing something that deserves to be named.
None of that is forgiveness. That is either denial or performance, and neither of them produces the physiological changes that genuine forgiveness produces.
What the research actually defines forgiveness as — and this matters, because the operational definition is what the studies are testing — is the internal release of resentment, bitterness, and the desire for retribution towards someone who has caused harm. It is a change in the emotional and cognitive relationship with what happened, not a change in the external relationship with the person who caused it.
Forgiveness, in this sense, has no necessary relationship to:
- Reconciliation — you can forgive someone and never speak to them again
- Trust — you can forgive someone and not trust them with the same things again
- Condoning — releasing resentment does not mean the harm was acceptable
- Forgetting — remembering clearly what happened is not incompatible with releasing the emotional charge around it
- Contact — the person doesn’t need to be involved, aware, or even alive
Forgiveness is not something you do for the person who harmed you. It is something you do for the body that has been carrying the harm ever since.
Don’t forget
The second part of the title is as important as the first.
Memory serves a function. The memory of being harmed — clearly held, accurately encoded, neither minimised nor catastrophised — is information your nervous system uses to navigate future situations. It tells you who is safe and who isn’t. What relationships to invest in and which to approach with caution. What patterns of behaviour in others preceded harm before and may precede it again.
Forgetting this — whether through genuine amnesia, deliberate suppression, or the kind of premature forgiveness that papers over something unresolved — removes useful data from the system. The person who forgives too quickly, before they have fully understood what happened and updated their model of the world accordingly, often finds themselves in the same situation again. A different person, the same dynamic.
The clinical goal is not to erase the memory. It is to change the relationship with it — from a live emotional wound that activates the stress response every time it surfaces, to a clear factual record that informs decisions without hijacking the nervous system.
That distinction — between a memory that informs and a memory that activates — is one of the most useful frames I have found in thirty-seven years of practice. Not as a therapeutic technique, but as a way of helping people understand what they are actually trying to do when they work on something difficult from their past.
The justified grievance
I want to spend some time on this because it is where most people get stuck.
The grievance is justified. The harm was real. The person — or institution, or system — was genuinely wrong. The anger is proportionate and rational. All of this can be true, and it is frequently true, and the fact that it is true has no bearing whatsoever on what carrying the resentment is doing to your cortisol curve.
This is the part that people find most difficult to accept, because it seems to suggest that the physiological cost of resentment is somehow an additional injustice — that not only were you harmed, but now you have to do the emotional work of releasing the very reasonable response to being harmed, while the person who harmed you does nothing. This feels profoundly unfair. It is profoundly unfair.
It is also simply how the biology works.
The body does not add a footnote to the cortisol response noting that this activation is based on a justified grievance and therefore does not count towards the chronic stress total. The immune suppression that follows sustained cortisol elevation does not exempt people whose anger is righteous. The cardiovascular consequences of chronic sympathetic activation do not make exceptions for those who have been genuinely wronged.
The injustice of the original harm and the physiological cost of continuing to carry it are two separate things. The first cannot be undone. The second can be addressed — but only by the person carrying it, and only for their own benefit.
In clients with persistently elevated evening cortisol, disrupted sleep, and a presentation that doesn’t fully resolve with nutritional and lifestyle intervention, I often find — if the clinical relationship is strong enough to go there — a long-held grievance that has never been processed. Not always. But often enough that I now consider it part of the assessment.
The DUTCH Plus gives us the cortisol pattern. The conversation gives us the context. Sometimes the most important clinical variable isn’t on the test panel at all.
What forgiveness actually requires
I am not going to give you a five-step protocol here. The evidence on structured forgiveness interventions — and there is a reasonable body of it, mostly coming out of Robert Enright’s work and the Forgiveness and Reconciliation Research Group — suggests that process matters, and that the process is different for different people and different harms.
What I can say, from clinical observation rather than a therapeutic framework, is that genuine forgiveness usually involves at minimum three things that are often skipped in the rush to feel better about the situation.
First, a clear and honest account of what actually happened — not minimised, not catastrophised, but seen as accurately as possible. This requires sitting with something uncomfortable rather than softening it prematurely.
Second, full acknowledgement of the impact — what it cost, how it changed things, what was lost. Forgiveness that arrives before the grief has been felt is usually performance. The grief is part of the process, not an obstacle to it.
Third, a decision — and it is a decision, not a feeling — to release the claim on retribution. Not because the harm didn’t warrant it. Because carrying the claim is costing more than it is returning.
None of this requires the other person. It does not require their acknowledgement, their apology, or their awareness. It is an internal process that happens in your nervous system, not in the relationship. The relationship may or may not change as a result. The physiology will.
A clinical observation, carefully anonymised
I worked with someone for over a year. Complex presentation — gut, hormones, energy, sleep. We made progress on all fronts. The DUTCH improved. The GI-MAP improved. The blood chemistry moved in the right direction across almost every marker.
The sleep remained broken. Not fragmented — broken in the specific way that suggests something is activating the nervous system in the middle of the night. Three in the morning, reliably. Lying awake, mind active, unable to return to sleep for one to two hours.
It took a long time to get to it. They had a sibling. A falling-out that had happened fifteen years earlier over something that was, by any objective measure, a genuine betrayal. They hadn’t spoken since. They said they’d moved on.
What they were doing at three in the morning — when I asked, directly, what was in their head during those hours — was rehearsing the argument. Refining the case. Finding the precise formulation that would, if delivered, make the other person finally understand the full extent of what they had done.
Fifteen years of preparation for a conversation that would never happen, at three in the morning, on a cortisol spike that the test results could see but the intake form couldn’t.
We didn’t fix it in a session. But naming it changed something. The first step is usually just recognising what you are actually doing with the energy — and asking whether the return justifies the cost.
If the cortisol pattern doesn’t fit the story, there’s more story
The DUTCH Plus gives us the full diurnal cortisol curve. When the pattern is persistently dysregulated despite solid nutritional and lifestyle work, the missing variable is often something the test can identify but not explain. That explanation happens in the consultation. Book a free discovery call to start.
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