The culprit is our autonomic nervous system in charge of preparing us to get out of dangerous situations. And it responds with its two parts: sympathetic and parasympathetic. The sympathetic system releases epinephrine , which speeds up our heart rate so that more oxygen enters the heart, increases lung capacity and respiratory rate, sharpens the visual and auditory senses, carries more blood to the muscles …, in short, it facilitates a possible escape. When we are faced with very tense situations, this alert mechanism kicks in, causing us to stutter. Once the sensation has passed, the parasympathetic system ensures that we regain a normal rhythm.
Why does our voice shake when we are nervous?
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