Pressor response to passive walking-like exercise in spinal cord-injured humans.
OBJECTIVE
To examine blood pressure responses during passive walking-like exercise in the standing posture (PWE) in spinal cord-injured (SCI) humans.


METHODS
Twelve motor-complete SCI individuals (cervical level 6 to thoracic level 12, ASIA grade: A or B) and twelve able-bodied controls (CON) participated in this study. SCI individuals were divided into a group with injury level at or above thoracic (T) 6 (HSCI, n = 7) and a group with injury level at or below T10 (LSCI, n = 5). Subjects carried out 6-minute quiet standing and then 12-minute PWE at 1 Hz using a gait training apparatus that enables subjects to stand and move their legs passively.


RESULTS
Mean arterial blood pressures (MAPs) at standing in HSCI, LSCI and CON were 69 +/- 5, 83 +/- 4 and 93 +/- 2 mmHg, respectively. MAP changed significantly during PWE only in HSCI and CON, increasing to 88 +/- 4 (P < 0.001) and 98 +/- 1 mmHg (P < 0.01), respectively. The former group showed a larger increase in MAP (P < 0.001).


CONCLUSIONS
Spinal sympathetic reflexes can be induced in a region isolated from the brainstem in response to a stimulus originating below the level of the spinal cord injury, and the magnitude of increase in blood pressure is greater in SCI individuals with lesion level at or above T6 due to loss of supraspinal control of the major sympathetic outflow. This central mechanism may be one of the reasons why greater pressor response to PWE was observed in HSCI.
Ogata
Hisayoshi
H
Dept. of Rehabilitation for Movement Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, 4-1 Namiki, Tokorozawa, Saitama, 359-8555, Japan. hisaoga@rehab.go.jp
Higuchi
Yukiharu
Y
Ogata
Toru
T
Hoshikawa
Shinya
S
Akai
Masami
M
Nakazawa
Kimitaka
K
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D004576:Electromyography; D005080:Exercise Test; D005081:Exercise Therapy / Q000009:adverse effects* / Q000379:methods*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D010101:Oxygen Consumption; D011187:Posture / Q000502:physiology; D011311:Pressoreceptors / Q000503:physiopathology*; D013116:Spinal Cord / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000503:physiopathology / Q000534:rehabilitation*; D016138:Walking / Q000502:physiology*