Pressor response to passive walking-like exercise in spinal cord-injured humans

Abstract

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.

Hyperventilation during orthostatic challenge in spinal cord-injured humans

“…Since it is possible that arousal or attention by this instruction affects ventilatory response [2], we calculated the averages for 3 min in the 3-5 min of sitting as the value during sitting. In addition, we recently observed that apparent muscle spasms occur in the transition from sitting to standing and they tend to disappear within 30 s after the attainment of erect position [34]. Muscle spasms have been shown to lead to an increase in blood pressure possibly due to the muscle pump effect or spinal reflexes acting on the heart or on peripheral vessels [15].…”

Atypical autonomic dysreflexia during robotic-assisted body weight supported treadmill training in an individual with motor incomplete spinal cord injury

“…With harness suspension and aerobic exercise, the modulation of vascular and sensory feedback may be diminished secondary to the SCI. 12,14 A larger clinical matter, is the health cost-benefit analysis of exercise on cardiovascular health and the potential AD which may occur during robotic-assisted BWSTT for individuals with level of SCI at or above T6. 11,13,[14][15][16] The presence of atypical AD in this case report provides evidence that one individual with incomplete SCI experienced sharply increased BP during robotic-assisted BWSTT activities with exertional fatigue reported in only the 10th session manifesting as the only AD clinical symptom.…”

Unusual blood pressure response during standing therapy in tetraplegic man

“…During measurements, the temperature in the experimental room was set within the range of 23-25°C. Quiet sitting, quiet standing and PWE were carried out using a commercially available device (Easy Stand Glider 6000, Altimate Medical, Inc. USA) as reported elsewhere [8]. First, the subject spent 6 min in a sitting position and this was followed by a 6-min quiet standing period to determine the baseline levels for both sitting and standing states.…”

“…However, in the standing position, there are risks of orthostatic hypotension in individuals with SCI, especially in those with cervical (C) SCI [7], due to loss of supraspinal control of spinal segments controlling sympathetic outflow. With regard to this problem, we recently demonstrated that the imposition of passive walking-like exercise (PWE) can increase blood pressure above the level at quiet standing in individuals with motor-complete SCI at or above thoracic (T) 6 (C6-T6) [8]. This enables blood pressure to maintain a similar level to that during quiet sitting and therefore suggests that PWE has the potential to inhibit orthostatic hypotension [8].…”

“…With regard to this problem, we recently demonstrated that the imposition of passive walking-like exercise (PWE) can increase blood pressure above the level at quiet standing in individuals with motor-complete SCI at or above thoracic (T) 6 (C6-T6) [8]. This enables blood pressure to maintain a similar level to that during quiet sitting and therefore suggests that PWE has the potential to inhibit orthostatic hypotension [8].…”