Respiratory patterns in the awaken state are dependent on arousal level, emotional state and personality traits, as the final respiratory output results from the interaction between what is required from our metabolism and our behavior.
For example, fear and anxiety increase respiratory frequency (i.e., number of breaths per minute) and minute ventilation (i.e. passage of air to and from the lungs) with no change in metabolism. High trait anxiety (i.e., related to personality, more long-term), on the other hand, leads to a decrease in end tidal carbon dioxide (i.e., a measurement unit referring to the amount of carbon dioxide -Co2 -that is in an expiration).
Idiopathic hyperventilation (IH) is a form of hyperventilation that has no obvious organic cause and that includes symptoms such as shortness of breath, dizziness and paraesthesia (sensation of burning or tingling in the limbs). The current study reports an association between high trait anxiety, high respiratory frequency and breathlessness in individuals with IH, which implies that having an anxious personality may contribute to the increase in breathlessness in IH. The researchers argue that stress and anxiety affect muscle tone by increasing intercostal muscle (i.e., chest muscles) contraction which is then perceived as shortness of breath.
Reference: Masaoka Y, Jack S, Warburton CJ, Homma I. Breathing patterns associated with trait anxiety and breathlessness in humans. Jpn J Physiol. 2004;54(5):465-470. doi:10.2170/jjphysiol.54.465