title: Effects of body weight-supported treadmill training on heart rate variability and blood pressure variability in individuals with spinal cord injury.
abstract: Individuals with spinal cord injury are prone to cardiovascular dysfunction and an increased risk of cardiovascular disease. Body weight-supported treadmill training (BWSTT) may enhance ambulation in individuals with incomplete spinal cord injury; however, its effects on cardiovascular regulation have not been investigated. The purpose of this study was to examine the effects of 6-mo of BWSTT on the autonomic regulation of heart rate (HR) and blood pressure (BP) in individuals with incomplete tetraplegia. Eight individuals [age 27.6 yr (SD 5.2)] with spinal cord injury [C4-C5; American Spinal Injury Association B-C; 9.6 yr (SD 7.5) postinjury] participated. Ten-minute HR and finger arterial pressure (Finapres) recordings were collected during 1) supine rest and 2) an orthostatic stress (60 degrees head-up tilt) before and after 6 mo of BWSTT. Frequency domain measures of HR variability [low-frequency (LF) power, high-frequency (HF) power, and LF-to-HF ratio] and BP variability (systolic and diastolic LF power) were used as clinically valuable indexes of neurocardiac and neurovascular control, respectively. There was a significant reduction in HR [61.9 (SD 6.9) vs. 55.7 beats/min (SD 7.7); P=0.05] and LF-to-HF ratio [1.23 (SD 0.47) vs. 0.99 (SD 0.40); P < 0.05] after BWSTT. There was a significant reduction in LF systolic BP [183.1 (SD 46.8) vs. 158.4 mmHg2 (SD 45.2); P < 0.01] but no change in BP. There were no significant effects of training on HR variability or BP variability during 60 degrees head-up tilt. In conclusion, individuals with incomplete tetraplegia retain the ability to make positive changes in cardiovascular autonomic regulation with BWSTT without worsening orthostatic intolerance.
authors.affiliation: Dept. of Kinesiology, McMaster Univ., 1280 Main St. West, Hamilton, Ontario, Canada L8S 4K1. dditor@uwo.ca
authors.forename: David S
authors.initials: DS
authors.lastname: Ditor
authors.forename: Mark V
authors.initials: MV
authors.lastname: Kamath
authors.forename: Maureen J
authors.initials: MJ
authors.lastname: MacDonald
authors.forename: Joanne
authors.initials: J
authors.lastname: Bugaresti
authors.forename: Neil
authors.initials: N
authors.lastname: McCartney
authors.forename: Audrey L
authors.initials: AL
authors.lastname: Hicks
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001835:Body Weight; D002574:Cervical Vertebrae / Q000293:injuries; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D005082:Physical Exertion; D013119:Spinal Cord Injuries / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D016474:Weight-Bearing