The short answer
Fear of public speaking — sometimes called glossophobia — is remarkably widespread. Research estimates put it at around 75% of people experiencing at least some nervousness about speaking in front of others, with a smaller group, somewhere around 5 to 10%, experiencing a more severe, functionally impairing version. It's frequently cited as one of the most commonly reported fears across surveys, in some cases ranking ahead of fears that seem, on paper, more objectively dangerous.
The overthinking that precedes speaking up — in a meeting, a presentation, even a single comment in a group — is closely related but not identical to full glossophobia. It's the anticipatory version: rehearsing, revising, and often abandoning what to say well before the moment to say it arrives.
The research
Some anxiety improves performance up to a point, and beyond that threshold it starts to actively degrade it — a relationship known as the Yerkes-Dodson law.
— Yerkes and Dodson, 1908
Why the anticipation is often the worst part
Anxiety researchers distinguish between the anxiety that occurs during a feared event and the anticipatory anxiety that builds beforehand, and for public speaking specifically, the buildup is often reported as more distressing than the speaking itself. That tracks with affective forecasting research more broadly: people tend to overestimate how bad an anticipated event will feel, a documented pattern researchers call the impact bias. The rehearsal happening in the 20 minutes before a meeting comment is frequently modeling a worse outcome than what's statistically likely to occur.
Why some arousal actually helps, and too much doesn't
A long-standing finding in performance psychology describes a specific relationship between arousal and performance: some anxiety improves performance up to a point, and beyond that threshold it starts to actively degrade it. That threshold is genuinely different for different people and different tasks, which is part of why generic advice like "just relax" or "just be confident" lands inconsistently — it's not accounting for where an individual's actual threshold sits.
This reframes the overthinking somewhat. The goal isn't to eliminate all anxious anticipation before speaking — some of it is doing useful preparatory work. The goal is recognizing when the anticipation has crossed from useful rehearsal into a spiral that's actively working against the moment it's supposedly preparing for.
Why the fear so often outranks the actual risk
Public speaking anxiety is unusual in how disproportionate it can feel relative to the actual stakes. A comment in a team meeting rarely carries the consequences the anticipatory dread implies, yet surveys have found more than half of people say they'd go to significant lengths to avoid speaking to a group. Part of the explanation is social: humans are highly attuned to the risk of public judgment, and a room full of attention functions, at a nervous-system level, like a spotlight with real evaluative stakes attached, even when the actual downside of an imperfect comment is small.
Want to see this pattern in your own thinking, not just in the research?
What tends to help
Because a meaningful part of this is anticipatory rather than reactive, interventions that work during the moment of speaking (breathing techniques, grounding) often don't touch the overthinking that happens well before, in the hour or the day leading up to it. What's more directly useful is tracking the anticipatory window itself — noticing how far in advance the spiral tends to start, and, over repeated instances, how often the anticipated worst case actually happened. Most people who track this specifically find the gap between the forecast and the outcome is wider than it feels in any single moment of dread.