Central and peripheral hemodynamic responses to passive limb movement: the role of arousal

Am J Physiol Heart Circ Physiol. 2012 Jan 1;302(1):H333-9. doi: 10.1152/ajpheart.00851.2011. Epub 2011 Oct 14.

Abstract

The exact role of arousal in central and peripheral hemodynamic responses to passive limb movement in humans is unclear but has been proposed as a potential contributor. Thus, we used a human model with no lower limb afferent feedback to determine the role of arousal on the hemodynamic response to passive leg movement. In nine people with a spinal cord injury, we compared central and peripheral hemodynamic and ventilatory responses to one-leg passive knee extension with and without visual feedback (M+VF and M-VF, respectively) as well as in a third trial with no movement or visual feedback but the perception of movement (F). Ventilation (Ve), heart rate, stroke volume, cardiac output, mean arterial pressure, and leg blood flow (LBF) were evaluated during the three protocols. Ve increased rapidly from baseline in M+VF (55 ± 11%), M-VF (63 ± 13%), and F (48 ± 12%) trials. Central hemodynamics (heart rate, stroke volume, cardiac output, and mean arterial pressure) were unchanged in all trials. LBF increased from baseline by 126 ± 18 ml/min in the M+VF protocol and 109 ± 23 ml/min in the M-VF protocol but was unchanged in the F protocol. Therefore, with the use of model that is devoid of afferent feedback from the legs, the results of this study reveal that, although arousal is invoked by passive movement or the thought of passive movement, as evidenced by the increase in Ve, there is no central or peripheral hemodynamic impact of this increased neural activity. Additionally, this study revealed that a central hemodynamic response is not an obligatory component of movement-induced LBF.

Publication types

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

MeSH terms

  • Adult
  • Afferent Pathways / physiopathology
  • Analysis of Variance
  • Arousal*
  • Blood Flow Velocity
  • Blood Pressure
  • Feedback, Sensory
  • Female
  • Heart Rate
  • Hemodynamics*
  • Humans
  • Lower Extremity / blood supply*
  • Lower Extremity / innervation*
  • Male
  • Middle Aged
  • Movement*
  • Perception
  • Pulmonary Ventilation
  • Regional Blood Flow
  • Spinal Cord Injuries / physiopathology*
  • Spinal Cord Injuries / psychology*
  • Stroke Volume
  • Time Factors
  • Utah