Cardiorespiratory response to physical exercise and psychological variables in panic disorder.

OBJECTIVE To investigate the possible influence of psychological variables on cardiorespiratory responses and perceived exertion of patients with Panic Disorder (PD) during a submaximal exercise test. METHOD Ten outpatients with PD and 10 matched healthy subjects walked up on a treadmill slope at a speed of 4 km/h in order to reach 65% of their maximum heart rate. Cardiorespiratory variables were continuously recorded. Before the exercise, the state and trait anxiety (State-Trait Anxiety Inventory scores), fear of physical sensations (Body Sensation Questionnaire scores), and fear of autonomic arousal (Anxiety Sensitivity Index scores) were assessed; during the exercise, levels of anxiety (VAS-A) and exertion (Borg Scale CR 10) were measured. RESULTS Compared to controls, patients reached earlier the target HR and the ventilatory threshold, showed lower oxygen consumption, higher HR and lower within-subject standard deviations of HR (a measure of cardiac variability). Exertion was also higher, and there was a significant correlation between breathing frequency, tidal volume and HR. No significant associations were found between cardiorespiratory response, perceived exertion, and psychological variables in patients with PD. CONCLUSION Although patients with PD presented poor cardiorespiratory fitness and were required to spend more effort during physical exercise, this did not appear to be related to the psychological variables considered. Further studies with larger groups are warranted.