Acta physiologica
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Comparative Study Clinical Trial
Chest wall kinematics, respiratory muscle action and dyspnoea during arm vs. leg exercise in humans.
We hypothesize that different patterns of chest wall (CW) kinematics and respiratory muscle coordination contribute to sensation of dyspnoea during unsupported arm exercise (UAE) and leg exercise (LE). ⋯ Leg exercise and UAE are associated with different patterns of CW kinematics, respiratory muscle coordination, and production of dyspnoea.
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Effective arterial elastance (Ea), an index of arterial load, increases with elevations in left ventricular elastance to maximize the efficiency of left ventricular stroke work during exercise. Systemic arterial compliance (C) and vascular resistance (R) are the primary components contributing to Ea, and R plays a greater role in determining Ea at rest. We hypothesized that the contribution of C to Ea increases during exercise to maintain an optimal balance between arterial load and ventricular elastance, and that the increase in Ea is due primarily to a reduction in C. ⋯ The present results suggest that the contribution of systemic arterial compliance to effective arterial elastance increases during exercise. Therefore, we propose that the increase in arterial load during exercise is mainly driven by a reduction in systemic arterial compliance.