The effect of lower body positive pressure on the cardiovascular response to exercise in sedentary and endurance-trained persons with paraplegia.

Autor: Kaprielian, Roger, Plyley, Michael J., Klentrou, Panagiota, Goodman, Leonard S., Goodman, Jack M.
Zdroj: European Journal of Applied Physiology & Occupational Physiology; Jun1998, Vol. 78 Issue 2, p141-147, 7p
Abstrakt: Exercise intolerance in persons with paraplegia (PARAS) is thought to be secondary to insufficient venous return and a subnormal cardiac output at a given oxygen uptake. However, these issues have not been resolved fully. This study utilized lower-body positive pressure (LBPP) as an intervention during arm crank exercise in PARAS in order to examine this issue. Endurance-trained (TP, n= 7) and untrained PARAS (UP, n= 10) with complete lesions between T6 and T12, and a control group consisting of sedentary able-bodied subjects (SAB, n= 10) were tested. UP and TP subjects demonstrated a diminished cardiac output (via CO2 rebreathing) during exercise compared to SAB subjects. Peak oxygen uptake ( V˙O2peak) remained unchanged for all groups following LBPP. LBPP resulted in a significant decrease in heart rate (HR) in UP and TP ( P≤0.05), but not SAB subjects. LBPP produced an insignificant increase in cardiac output ( Q˙) and stroke volume (SV). The significant decrease in HR in both PARA groups may indicate a modest hemodynamic benefit of LBPP at higher work rates where circulatory sufficiency may be most compromised. We conclude that PARAS possess a diminished cardiac output during exercise compared to the able-bodied, and LBPP fails to ameliorate significantly their exercise response irrespective of the conditioning level. These results support previous observations of a lower cardiac output during exercise in PARAS, but indicate that lower-limb blood pooling may not be a primary limitation to arm exercise in paraplegia. [ABSTRACT FROM AUTHOR]
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