Effect of anxiety on the function of the cardiorespiratory system

The effects of anxiety on the external respiration system and respiratory sinus arrhythmia (RSA) were studied in healthy subjects in real-life conditions. Changes in external respiration parameters and heart rate variability (HRV) in students going to take their end-of-term exams were assessed relative to a midterm period, and the cardiorespiratory system was monitored in a longitudinal study for 50 days. The function of the cardiorespiratory system was characterized by measuring external respiration parameters and calculating HRV parameters. State anxiety (SA) was assessed using Spielberger’s scale. An increase in SA before an exam was accompanied by a higher breathing rate, a higher tidal volume, and lower HRV indices, especially those related to respiratory sinus arrhythmia (HF and HF _norm). The changes in the parameters depended on the increase in SA. A negative correlation was observed between midterm HF and pre-exam SA. The longitudinal study revealed a distinct negative correlation between respiratory sinus arrhythmia parameters and peak expiratory flow (PEF) and a positive correlation between SA and PEF in the majority of subjects. Changes in cardiorespiratory parameters depended on the changes in SA in the longitudinal study. An increase in SA was accompanied by substantial changes in respiratory sinus arrhythmia (RAS) and external respiration parameters, and their correlation was assumed to indicate that modification of parasympathetic activity plays a leading role in increasing PEF.