Research shows that at rest breathing patterns are influenced by auditory and visual stimuli as well as emotional affects. Termed “ventilation personality”, those breathing patterns vary from one person to the next and they are repeated over long periods of time.
Notably, breathing patterns in anxiety present irregularities, especially when it concerns respiratory rates (i.e., how many breaths per minutes). For example, this study reports significant changes in the respiratory rates of individuals with anxiety that differ according to the type of anxiety and the type of action performed.
Incidentally, the latter results align with some of the symptoms of testing anxiety, namely shortness of breath.
Furthermore, another distinct breathing pattern associated with anxiety involves expiratory time (i.e., length of expiration). The time it takes to expel one’s breath is in fact influenced by individual anxiety levels, and for example expirations are typically shorter when there is an increase in anxiety.
Masaoka, Y., & Homma, I. (1999). Expiratory time determined by individual anxiety levels in humans. Journal of applied physiology, 86 4, 1329-36 .