Impact of acute active and passive stress on physiological responses in adults with asthma

Abstract

Background: Acute psychological stress is a trigger for asthma exacerbations. However, the physiological mechanisms of this remain poorly understood. The objective of the current study was to compare the impact of active vs. passive acute stressors on respiratory and cardiovascular measures in adults with asthma. Methods: Thirty-two physician-diagnosed asthma patients completed active (mental arithmetic) and passive (stressful pictures) stress tasks in a counterbalanced order. Blood pressure [SBP, DBP], heart rate [HR], impedance cardiography, ventilation responses, and spirometry were collected. Results: Both tasks were associated with increased sympathetic activity (e.g., total peripheral resistance, stroke volume, cardiac output, HR, SBP, DBP) with greater responses to active stress. The active stress task was associated with an increase in ventilation responses (increases in VO2, VCO2, VE, breathing frequency [BF], and respiratory exchange ratio [RER]). For the passive stress task, there was a decrease in VCO2 and RER. Neither task impacted the caliber of bronchi (FEV1 and FVC). The effect size for these changes were generally small except BF, HR, and DBP (medium) and SBP (large). Conclusions: This study provides evidence that acute stress negatively influences the physiology of asthma patients. Active and passive stressors have differential impacts on respiratory and cardiovascular responses in adults with asthma. The active stress task seemed to be associated with increased metabolic work without affecting the caliber of bronchi and the passive task was associated with decreased CO2 production potentially suggesting hypocapnia.