The window of tolerance: why you sometimes flood and sometimes go numb

“When I shout, at least you hear me. But when you go quiet, it’s as if you’re not even in the room.”

The argument began over something small, as most do. She was talking faster and louder, her heart pounding, words coming out before she had thought them through. He sat looking at the floor, feeling his head empty out. He wasn’t sulking and he wasn’t trying to wind her up. He simply couldn’t answer any more. Later he told me he barely remembered that conversation — only a kind of rushing sound in his ears.

Two people, one room, one argument — and two completely opposite reactions. She was flooded, he went numb. Both of them were, as we say in the profession, outside the window of tolerance. In this post I will explain what this window is, why it sometimes narrows to almost a crack, how you can tell which side you’ve fallen out on, and what helps you come back.

What the window of tolerance is

The term window of tolerance was introduced in 1999 by the psychiatrist Daniel Siegel in his book The Developing Mind. He described a band of arousal within which a person can feel and think at the same time. Within this band you can be angry, sad or frightened and still stay in touch with yourself and with the other person: you hear what someone is saying to you, you can find words, you can decide what you will do. Feelings are strong, but you can carry them.

The window isn’t a state of perfect calm. Stress, excitement and grief belong in it too. What matters is only that they don’t sweep you away. When arousal goes over the top edge of the window, you move into flooding. When it drops below the bottom edge, you move into numbness. There is also a short explanation in the knowledge base under window of tolerance.

In 2006 Pat Ogden, Kekuni Minton and Clare Pain developed the model for trauma work and linked it to the responses of the autonomic nervous system. They noticed that people after severe experiences often don’t move calmly within the window, but jump from one extreme state to the other — from panic to emptiness and back — with no middle band in which they could think about what is happening.

Above the window: when you’re flooded

Flooding is a state most people know. The body prepares for fight or flight. The heart speeds up, breathing becomes shallow and fast, muscles tense, thoughts race. Attention narrows to the threat: you hear only the reproach, not the tone it was said in; you see only the frown, not the fact that the other person is frightened too.

In this state things happen that you later regret: you say too much, slam the door, leave mid-sentence. Or you have a panic attack, when you’re overwhelmed by the sense that something terrible is about to happen. I wrote about why the body reacts before you even think in What happens in the brain during anxiety.

The key thing to understand is that thinking doesn’t work well in this state. Advice like “calm down and think” doesn’t land, because the part of the brain that would do the thinking doesn’t have the main say right now. The body has to settle first.

Below the window: when you go numb

The other side is less well known and often misunderstood. When distress is too great and you can neither fight it nor get away, the nervous system can “switch off”. A person becomes empty, numb, slowed down. It’s hard to speak, hard to think; sometimes it feels as if you’re watching yourself from a distance or as if the world around you isn’t quite real. The body may feel heavy, or as if it isn’t yours.

From the outside this looks like indifference, stubbornness or punishment through silence. From the inside it is usually exactly the opposite: there is no will in it, only helplessness. The man in the opening scene didn’t “choose” not to answer. His nervous system judged that the distress was too much and turned it down. The extreme form of this switching off is dissociation — when you switch off to survive, and there is a short explanation in the knowledge base under dissociation.

Numbness isn’t only a matter of the moment. For some people it has become an almost permanent background: they spend their days “on autopilot”, don’t know what they feel, look forward to nothing. This can be a sign of prolonged overload, but it can also be a sign of depression, so it’s right to look at such a state with a doctor as well.

Why the window is narrower for some people

The window isn’t equally wide for everyone, and even for the same person it isn’t the same every day. A sleepless night, hunger, illness, chronic stress or a hard week at work narrow it for anyone. Just think how differently you react to the same remark on a Friday evening compared with a Sunday morning.

What narrows the window most lastingly, though, are severe and repeated experiences. Trauma is more common than we think: in World Health Organization surveys summarised in 2017 by Ronald Kessler and colleagues, covering adults in more than twenty countries, more than 70 per cent of respondents reported at least one traumatic event in their lifetime. Most people recover. In some, however, the nervous system stays set for danger — I wrote about how this happens in How trauma stays written in the body.

The window is often especially narrow in people who grew up without enough safety and comfort. A child doesn’t learn to regulate emotions alone, but alongside an adult who soothes them. If that wasn’t there, the adult often has no inner paths by which to return to the window. I write more about this in Developmental trauma: what happens when safety wasn’t there from the start.

In 2011 Frank Corrigan, Janina Fisher and David Nutt described how, in people with complex trauma, these two extremes — arousal and shutdown — alternate more unpredictably and with less middle ground. That is why such people are often needlessly labelled “oversensitive” or “cold”, when both descriptions are simply two sides of the same narrow window.

Polyvagal theory: useful language, contested foundations

When you read about the window of tolerance, you will almost certainly come across Stephen Porges’s polyvagal theory. It explains flooding and numbness through different branches of the nervous system and talks about “safe”, “mobilised” and “frozen” states. It is very popular among therapists, because it gives people simple language for something they experience.

It’s only fair to say, however, that the theory’s physiological basis is contested in science. In 2023 the psychologist Paul Grossman argued in an extensive critical review that several of its basic premises about how the vagus nerve works do not fit the existing evidence from physiology and comparative biology. So the window of tolerance as a descriptive model doesn’t stand or fall with polyvagal theory. It is a map of experience, not an anatomical blueprint. And as a map, it is useful.

The window in a couple: two nervous systems in one room

As a marriage and family therapist in training, what interests me most about the window of tolerance is how it plays out in relationships. When two people argue, it isn’t only two opinions that meet, but two nervous systems. And they affect each other: one person’s loudness pushes the other into shutdown, and the other’s shutdown pushes the first into even greater loudness. This creates a loop that many couples know.

This is how a conversation with the couple from the opening might have sounded when they talked about the argument a few days later (composed, not real people):

“When he goes quiet, I feel he doesn’t care. So I talk louder.”
“When you talk louder, my head goes empty. I can’t answer, even if I want to.”
“Why have you never told me that?”
“Because in the moment I don’t know. I only know now.”
“What would help you stay?”
“If you said you’re angry but you’re not leaving. And if you gave me a minute.”

Something important happens in this short excerpt: for the first time both of them see that what they had taken for the other’s intention wasn’t an intention, but a state. That doesn’t resolve the disagreement, but it opens up room to talk about it once both are back in the window. I described how to take a break without leaving the other person on their own in Taking a break in an argument: how to step away without walking out. The foundation of this is co-regulation — two nervous systems can also calm each other, not only stir each other up.

How to get back into the window

The way back depends on which side you fell out on. When you’re above the window, you need something that slows the body down. When you’re below it, you need something that gently brings you back into your body and into the present. A mistake I often see is people using the same tool for both — for instance deep relaxation when they’re numb, which can push them even deeper.

When you’re flooded, what often helps is a longer out-breath (the breathing with a longer out-breath exercise), feeling your feet on the floor, stepping away from a screen or a conversation for an agreed time, and slow movement such as walking. When you go numb, what more often helps is orientation — letting your eyes find something in the room and naming it — the 5–4–3–2–1 grounding exercise, something cold or warm in your hands, standing up and moving your body.

In the long run, though, it isn’t only about getting back, but about the window gradually widening. This happens slowly: with enough sleep, with relationships in which it is safe to feel, and with the experience that you can bear distress without being swept away. Trauma methods do this deliberately. Sensorimotor psychotherapy (developed by Pat Ogden) and Somatic Experiencing (Peter Levine) work with small bodily sensations and dose distress a little at a time, so that a person stays close to the edge of the window rather than going over it. EMDR uses bilateral stimulation while memories are processed. These methods are practised by therapists with specific training — I don’t practise them myself.

Exercise: a map of your window

You can do this exercise today, on a sheet of paper. It takes about ten minutes, ideally at a time when you’re calm — in other words, in the window.

1. Draw three horizontal bands: “too much” at the top, “I can manage” in the middle, “too little” at the bottom.
2. In each band, write how you recognise it in your body — not in your thoughts. For example: a hot face and clenched jaw at the top, soft shoulders in the middle, heavy arms and fog at the bottom.
3. Next to the top and bottom bands, write your typical triggers. What most often pushes you over the edge? Criticism, shouting, silence, tiredness?
4. For each band, write one thing that brings you at least a little back towards the middle. Not the ideal one, but one you have already tried.
5. If you live with a partner, show them your map and ask for theirs. Agree on one sentence you can use to tell each other you’ve fallen out of the window.

The map isn’t a test. It’s a reminder for the moments when thinking fails — then it’s easier to look at a sheet you wrote in calm than to remember what you were supposed to do.

If you do the exercise as a couple, watch out for one trap: the other person’s map isn’t a tool for telling them when they’re “outside the window”. It’s information about how you can help them, and how they can help you.

Where the model falls short

The window of tolerance is one of the most useful models I know, but it has limits.

It is a metaphor, not a measurement. Nobody can measure how wide your window is. The model helps put an experience into words; it doesn’t make a diagnosis. If someone uses it as a scientific fact with precise boundaries, they are overstating it.

Sometimes the alarm is right. If you live with someone who intimidates you or is violent, your flooding or numbness isn’t a fault in regulation, but a reasonable response to danger. Then the task isn’t to learn to stay calm, but to make sure you’re safe. In Slovenia there is the SOS helpline for women and children who are victims of violence on 080 11 55, and if you are in danger call the police on 113 or 112 in Slovenia.

Not all numbness comes from distress. Tiredness, emptiness and slowness can have physical causes — from thyroid problems to iron deficiency or side effects of medication — or they can be a sign of depression. If such a state lasts for weeks, go to your GP first.

The window isn’t a weapon. In couples I have seen the model’s language used against the other person: “You’re out of your window again, there’s no talking to you.” Used like that, it becomes just a new way of taking away the other person’s right to their feelings. Anger is sometimes entirely justified — and it can be expressed from within the window too.

And one last thing: distress doesn’t make you stronger by itself. The window doesn’t widen by exposing yourself to too much over and over, but by experiencing distress in doses you can manage — and by not being alone while you do.

When to seek help

If you often fall out of the window, if numbness or flooding shape your days, or if you notice that you switch off and lose stretches of time, it’s right to look for professional help. With pronounced after-effects of trauma, look for a psychotherapist with additional training in trauma work; with depression, severe sleep problems or panic attacks, talk to your GP or a psychiatrist as well.

In couples therapy and family therapy, in which I am training, the window of tolerance is often in the background of the work even when we don’t name it: how a couple can talk without one of them falling out, and how they find each other again after an argument. This isn’t trauma treatment, but it can be an important part of a relationship becoming a place where the window slowly widens. I also work with English-speaking clients, in person in Ljubljana.

If things are very hard right now, or if you are having thoughts of not wanting to live, in Slovenia call the Mental Distress Line on 01 520 99 00 (every day from 19.00 to 7.00) or the Samaritans helpline on 116 123 (24 hours a day). In an emergency call 112.

What to remember

• The window of tolerance is the band of arousal in which you can feel and think at the same time — it isn’t a state of perfect calm.
• Above the window is flooding (fight, flight, panic), below it numbness (emptiness, shutting down). Both are responses of the nervous system, not choices.
• Lack of sleep, stress and illness narrow the window; severe and early experiences narrow it most lastingly.
• The way back differs: above the window you slow the body down, below it you gently wake it up. In the long run the window widens in safe relationships.
• The model is a metaphor, not a diagnosis — and when you are in danger, your alarm is right.