Can Plasma Volume Affect Arterial Stiffness and Autonomic Modulation Response to Resistance Exercise?

Introduction : Despite the numerous benefits of resistance exercise (RE), stress caused by muscle contractions may cause transient disturbances in the cardiovascular system including arterial stiffness increasing the temporary risk of cardiovascular events. One physiological response which can influence this process but has received little attention from the scientific community is plasma volume (PV). Discussion : Recent reviews point to a complex interaction between autonomic modulation, central and peripheral adjustments triggered by a RE session. After the end of a moderate to high intensity RE session there may be a reduction in PV caused by its influx into the interstitial tissue and consequent decline in stroke volume and venous return. Moreover, there is an increase in sympathetic modulation, and a decrease in parasympathetic modulation. Arterial stiffness is one of the first signs of pathological changes in the arterial wall leading to an increased risk of cardiovascular events. The stiffening of the main arteries of the body can also be negatively affected by PV reduction. The PV reduction would lead to elevation of sympathetic nerve modulation, cardiac workload and reduction in cardiac perfusion. However, depending of the nature of the PV reduction contradictory results emerges and decrease in arterial stiffness was also reported. Conclusion : There is no agreement as to why PV reduction may affect arterial stiffness, and several questions regarding hydration status and RE influence remains to be addressed. Future studies should standardize water intake and control hydration status before and during experimental sessions utilizing simple measures of hydration status.