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

Arch Phys Med Rehabil. 2018 Mar;99(3):423-432. doi: 10.1016/j.apmr.2017.06.033. Epub 2017 Aug 9.

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 (FEV1), 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 FEV1 (both P<.01) in association with improved quality of sleep, cough, and speech. Sympathetically (phase II) and parasympathetically (phase IV) mediated baroreflex sensitivity both significantly (P<.05) increased during the 5s MEP. During the orthostatic stress test, improved autonomic control over heart rate was associated with significantly increased sympathetic and parasympathetic modulation (low- and high-frequency change: P<.01 and P<.05, respectively).

Conclusions: Inspiratory-expiratory pressure threshold RT is a promising technique to positively affect both respiratory and cardiovascular dysregulation observed in persons with chronic SCI.

Trial registration: ClinicalTrials.gov NCT02396823.

Keywords: Autonomic nervous system; Blood pressure; Breathing exercises; Hypotension; Rehabilitation; Respiration; Spinal cord injuries.

Publication types

  • Clinical Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Autonomic Nervous System / physiopathology
  • Baroreflex / physiology*
  • Case-Control Studies
  • Chronic Disease
  • Female
  • Forced Expiratory Volume
  • Heart Rate / physiology*
  • Humans
  • Male
  • Middle Aged
  • Respiratory Mechanics / physiology
  • Respiratory Therapy / methods*
  • Spinal Cord Injuries / physiopathology*
  • Spinal Cord Injuries / therapy*
  • Treatment Outcome
  • Vital Capacity
  • Young Adult

Associated data

  • ClinicalTrials.gov/NCT02396823