Public speaking fear is a breathing problem more often than a confidence problem
The mind going blank on stage has a physical cause, and it responds to physical training far better than it responds to being told to relax.
The unhelpful advice
Anyone who has admitted to a fear of public speaking has been told to imagine the audience in their underwear, to remember that nobody is really watching, or simply to be more confident. None of this works, because none of it addresses what is physically happening.
What is physically happening
Under adrenaline, most people breathe high in the chest and stop refilling between sentences. That has four consequences in quick succession. The voice thins, because there is not enough air behind it. The pace increases, because you are racing to finish sentences before the air runs out. Pauses disappear, because there is no spare breath for silence. And thinking becomes noticeably harder.
That fourth one deserves a correction I used to get wrong myself. It is not oxygen starvation. You are getting plenty of oxygen. Over-breathing does the opposite: it flushes out carbon dioxide, and low CO₂ raises the resistance of the brain’s blood vessels and cuts the flow through them — roughly 1 to 3 per cent less flow for every millimetre of mercury the CO₂ drops. That is the mechanism behind the lightheadedness and the fog. And people who already run low on CO₂ react more strongly to it: anxious patients who are chronically hypocapnic show measurably greater arousal during paced hyperventilation than anxious patients whose resting CO₂ is normal.
Adrenaline does the rest. Amy Arnsten’s review in Nature Reviews Neuroscience puts it plainly: even quite mild acute uncontrollable stress causes a rapid loss of prefrontal cognitive function, and working memory is exactly the faculty you are relying on to hold your next three sentences.
One detail from that research is worth sitting with. The factor that predicted impairment was not how severe the stress was, but whether the person felt they had control over it. Which is a reasonable argument for rehearsing until the talk feels like yours.
So “my mind went blank” is not a failure of nerve. It is a predictable outcome of over-breathing under stress, and both halves of it are trainable.
Which means it is trainable
Breath is under conscious control in a way that confidence is not. You cannot decide to feel calm. You can decide how fast you breathe.
What the evidence actually supports is slowing down, to somewhere around six breaths a minute. A 2025 scoping review of six studies found increases in the markers of parasympathetic activity in all six. That is a small evidence base, but it points one way, and it is the part to rely on.
The part I used to state too confidently is the ratio. Coaches, me included, have long taught that a long exhale beats an even one. When Meehan and Shaffer tested it directly in 2024, across an original experiment and a replication, they found no difference in heart rate variability between breathing 1:1 and 1:2 at six breaths per minute. Their recommendation was to default to the simpler 1:1, subject to what the person finds comfortable.
So: slow your breathing before you stand up, and it will do something measurable. Whether you make the out-breath longer is up to you.
The three things worth practising
First, low breathing: hand on the stomach, feel it move rather than the shoulders. Practise it while sitting at a desk, not while panicking on stage. Second, refilling at punctuation: take air at full stops deliberately, rather than when you run out. Third, slow breathing before you start: aim for roughly six breaths a minute (five counts in, five out is fine) for a minute or two. Unglamorous, and it holds up under conditions where visualisation does not.
The structural half
Breath handles the physiology. Structure handles the rest. Most people who lose their place do so because there was no place to lose: no fixed landmarks in the talk to return to. Build a talk with four or five points you could recite from memory in the corridor, and losing your thread becomes a two-second recovery instead of a crisis. Fear of freezing is largely fear of having nothing to return to.
This is the practical argument for picking a shape before you write. Of the five structures worth knowing, the numbered framework is the one to reach for when you are anxious, because it is the only one that survives being interrupted: if you are cut off during point two, you can take the question and come back with “so that was the second thing, the third is…” and nothing is lost. A hero’s journey broken in the middle is very hard to resume, which is a poor thing to discover while your pulse is up.
Rehearse in the wrong conditions on purpose
Practising a talk alone, calmly, at your desk trains you to deliver it alone, calmly, at your desk. Rehearse it standing, out loud, on camera, and ideally with someone interrupting you. Skills that only work in a calm room are not skills yet.
When this is not a coaching problem
I should be straight about the limits of what is above, because the word “fear” covers two quite different things and only one of them is mine to work on.
Ordinary nerves are worst in anticipation, settle within a minute or two of starting, and shrink with rehearsal and repetition. That is the whole subject of this piece, and it responds well to breath, structure and reps.
What I am describing is not clinical anxiety. If the fear is severe enough that you turn down work to avoid speaking, or it produces genuine panic symptoms, or it does not settle at all once you have started, that is a different thing and a coach is the wrong professional. So is a stammer or any diagnosed speech condition: the right person there is a speech and language therapist, and I will say so in the first session rather than take the booking.
There is no shame in either, and it is worth knowing which one you have before spending money on the wrong help. If you are unsure, a GP is a better first call than me.
What I won’t tell you
That the nerves go away. For most people they don’t, and the good speakers I work with mostly still get them. What changes is that the nerves stop taking the voice with them.
My public speaking course spends its first fortnight on exactly this, before touching content, and there is a lesson on it in the free public speaking course.
Sources
- Arnsten, A. F. T. (2009). Stress signalling pathways that impair prefrontal cortex structure and function. Nature Reviews Neuroscience, 10(6), 410–422.
- Giorgi, F., & Tedeschi, R. (2025). Breathe better, live better: the science of slow breathing and heart rate variability. Acta Neurologica Belgica.
- Meehan, Z. M., & Shaffer, F. (2024). Do longer exhalations increase HRV during slow-paced breathing? Applied Psychophysiology and Biofeedback, 49(3), 407–417.
- Tolin, D. F., O’Bryan, E. M., Davies, C. D., Diefenbach, G. J., & Johannesen, J. (2023). Central and peripheral nervous system responses to chronic and paced hyperventilation in anxious and healthy subjects. Biological Psychology, 176, 108472.
- Willie, C. K., Tzeng, Y.-C., Fisher, J. A., & Ainslie, P. N. (2014). Integrative regulation of human brain blood flow. The Journal of Physiology, 592(5), 841–859.
Common questions
Why does my mind go blank when I speak?
Over-breathing under adrenaline flushes out carbon dioxide, which narrows the brain's blood vessels and reduces flow. Adrenaline separately impairs working memory, which is the faculty holding your next three sentences. Both halves are physical, and both are trainable.
How do I calm my nerves before a speech?
Slow your breathing to roughly six breaths a minute for a minute or two before you stand up. Five counts in, five out. It is the only intervention here with measurable effects, and unlike "relax" or "be confident" it is something you can actually decide to do.
Will the fear of public speaking ever go away?
For most people, no, and the good speakers I work with mostly still get nervous. What changes is that the nerves stop taking the voice with them. Aiming at eliminating the feeling is what keeps people stuck; aiming at working while it happens is achievable.
Is fear of public speaking a phobia?
Sometimes. Ordinary nerves settle once you start and are worst in anticipation. If the fear causes you to avoid work, produces panic symptoms, or persists at full strength throughout, that is closer to a phobia and belongs with a clinical professional rather than a coach.