Effects of Respiratory Training on Heart Rate Variability and Baroreflex Sensitivity in Individuals With Chronic Spinal Cord Injury

Abstract Objective To evaluate the effects of pressure threshold respiratory training (RT) on heart rate variability and baroreflex sensitivity in persons with chronic spinal cord injury (SCI). Design Before-after intervention case-controlled clinical study. Setting SCI research center and outpatient rehabilitation unit. Participants Participants (N=44) consisted of persons with chronic SCI ranging from C2 to T11 who participated in RT (n=24), and untrained control subjects with chronic SCI ranging from C2 to T9 (n=20). Interventions A total of 21±2 RT sessions performed 5 days a week during a 4-week period using a combination of pressure threshold inspiratory and expiratory devices. Main Outcome Measures Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV 1 ), and beat-to-beat arterial blood pressure and heart rate changes during the 5-second-long maximum expiratory pressure maneuver (5s MEP) and the sit-up orthostatic stress test, acquired before and after the RT program. Results In contrast to the untrained controls, individuals in the RT group experienced significantly increased FVC and FEV 1 (both P P P P Conclusions Inspiratory-expiratory pressure threshold RT is a promising technique to positively affect both respiratory and cardiovascular dysregulation observed in persons with chronic SCI.