There is a particular thing that happens under pressure, and most of the language we have for it is wrong. We say stress makes us feel more: more anxious, more angry, more frayed. But that is not always what the women MoMo works with describe, and it may not be the most accurate account. The feeling, often, is roughly the size it would have been anyway. What changes is something quieter and harder to see: the moment before the response. The fraction of a second in which you would normally have chosen. That is the thing that seems to go missing.

I want to write about that gap: it is more interesting than the popular story, and the research on it is unsettled in a way worth being honest about.

The thing that goes is the stopping, not the feeling

The cleanest study I have found on this is a 2026 randomised controlled trial (large, by the standards of this literature, with 303 participants and a careful design).[1] The researchers stressed people in the lab and then tested three different cognitive capacities: visual perception, the ability to switch between tasks, and what is called response inhibition: the mechanism that lets you cancel an action you have already begun to make. The stop. The not-doing.

What they found was specific. Visual perception held. Task-switching held. The thing that degraded was the stopping mechanism, and it degraded in a particular window, roughly forty to eighty minutes after the stressor. Not in the first rush. Later, once the spike had passed.

I find the specificity striking. It maps onto something the women MoMo works with describe without the vocabulary for it: not that they felt a tidal wave under pressure, but that the brake was slow. The reply sent before it was thought through. The tone returned before the meaning of the other person's tone had landed. The yes given to something that needed a moment. The feeling was ordinary. The interval in which they could have done something other than react had narrowed.

Why I am not going to tell you this is settled

Here is where a tidy essay would stop. I am not going to, because the honest picture is messier, and the mess is the most interesting part.

That single trial points one way. Much of the literature before it points the other. A 2016 meta-analysis pooling twenty-one studies found that acute stress enhanced response inhibition: people got slightly better at stopping, not worse.[2] A 2020 neuroimaging study found the same direction: stress sharpened the stop, and the improvement tracked with stronger connectivity between the frontal cortex and the striatum, the circuit that does the cancelling.[3] So we have a rigorous new trial saying stress degrades the brake, and a body of careful prior work saying stress, if anything, tightens it.

They cannot both be right as flat statements. The most plausible reconciliation (and it is the new study's own interpretation, not a tested fact) is that timing decides the direction. Early after a stressor, in the first adrenaline-bright minutes, the stop may sharpen. Later, in a different physiological phase, it may slip. The earlier studies tended to test early; the new trial caught the later window. If that is right, then when you measure changes the answer entirely, which is why serious researchers ended up pointing in opposite directions without anyone being careless.

Two further limits matter for who is reading this. The trial enrolled healthy men only, so I cannot tell you it has been shown in women, and I am not going to imply otherwise. And although the late-window slip happened in the phase where cortisol is high, when the researchers manipulated cortisol directly it did not explain the effect. The tempting line (cortisol removes the brake) is not something the evidence supports. The mechanism is genuinely open. What we have is a precise observation and an unproven story about its cause.

A systems point, even with the science unfinished

Why write about a finding that has not been confirmed in women, whose mechanism is unknown, and which the prior literature partly contradicts?

Because the frame survives the uncertainty, and the frame is the part that helps.

The dominant cultural model treats pressure as a volume knob on feeling. Stressed means feeling-more, and acting badly is read as the overflow of too much emotion (a failure of will, something a stronger person would have contained). The research (in both of its conflicting directions) is describing a different system. It is not the size of the feeling that is the variable under pressure. It is a specific control mechanism (the stop) that responds to stress, and may respond differently depending on how long the pressure has been sitting in the body.

I have written before about how a short night degrades the brain's regulatory machinery (a separate route, a separate circuit, a separate post). This is a different mechanism with a different timeline, and I am wary of collapsing them. But they rhyme in one important way. The capacity to not-react is not a fixed trait you either have or lack on a given day. It is a system, with inputs, that gets reconfigured by things you are not choosing: a stressor forty minutes ago, a week of under-recovery. The output looks like character. The input was physiology.

That distinction is not an excuse, and I would not offer it as one. It is a more accurate place to stand. If the moment you could have chosen narrowed under pressure, that is not the same as choosing badly. The reaction that escaped is information about a system under load, not a verdict on the person running it.

Where this lands

You do not have to do anything with this. There is no routine here, no window to schedule your hard conversations around. The science is too unfinished to earn that, and you have been offered enough optimisation already.

But the next time something escapes before you had decided to let it (a sharper reply than you meant, an answer given before you had weighed it) it might be worth holding a different account than the one that reaches for fault. Under pressure, the brake may not work the way it does when you are unpressured. The research is still arguing about exactly how. That it is arguing about the brake, and not about how much you felt, is the part worth keeping.

Noticing that a hard moment connects back to a pressured hour, or a depleted week, so a pattern stops reading as a personal verdict and starts looking like a system you can actually see, is the kind of thread MoMo was built to hold across days. But that is a footnote. The essay is the brake. The brake is real, even where the science is unfinished.

If this resonates in a painful way (if you're in distress or crisis) please reach out: Mind Sweden 90101 | Samaritans UK 116 123 | your local crisis line.

References

Weckesser, L. J. et al. (2026). Acute stress selectively impairs response inhibition in a post-stress window. arXiv:2601.10515.
Shields, G. S., Sazma, M. A., & Yonelinas, A. P. (2016). The effects of acute stress on core executive functions: A meta-analysis and comparison with cortisol. Neuroscience & Biobehavioral Reviews. PMID: 27371161.
Chang, R., Hu, J., Li, S., & Yu, R. (2020). Acute stress improves response inhibition through enhanced fronto-striatal connectivity. NeuroImage. PMID: 31546050.

The circuit that runs on sleep (momocompanion.com/blog/the-circuit-that-runs-on-sleep) covers the sleep route to the same erosion: a distinct mechanism, not a restatement of this one.