Cardiovascular Adaptations to Exercise Training

Abstract

Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved contractility, and an increase in blood volume, allowing for greater filling of the ventricles and a consequent larger stroke volume. In parallel with the greater maximal cardiac output, the perfusion capacity of the muscle is increased, permitting for greater oxygen delivery. To accommodate the higher aerobic demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle allowing for an improved capacity for oxygen extraction by the muscle through a greater area for diffusion, a shorter diffusion distance, and a longer mean transit time for the erythrocyte to pass through the smallest blood vessels. The present article addresses the effect of endurance training on systemic and peripheral cardiovascular adaptations with a focus on humans, but also covers animal data.

Probenecid Inhibits α-Adrenergic Receptor–Mediated Vasoconstriction in the Human Leg Vasculature

“…Such an interaction between Panx1 channels and α-adrenoceptors would allow for a point of amplification and integration through which other signaling pathways could effectively modify the contractile response. With regard to the latter, skeletal muscle can increase blood flow during contractile activity substantially despite large increases in sympathetic outflow, 22 a phenomenon known as functional sympatholysis. 23 Hence, Panx1 channels may provide 1 point of intercept for vasodilator substances in contracting skeletal muscle.…”

The changes in maximal oxygen uptake (V̊O2MAX) induced by physical exertion during an Antarctic expedition depend on the initial V̊O2MAX of the individuals: a case study of the Brazilian expedition

“…The V̊O 2MAX increases resulting from aerobic training are largely mediated by augmented blood volume. This higher blood volume, in association with a greater cardiac contractility, increases stroke volume under resting, submaximal and maximal exercises, thereby reducing the HR required for maintaining a given cardiac output [8]. Thus, the reduction in HR for a given exercise intensity, as observed in researchers during the incremental test after the expedition, indicates a physiological adaptation induced by aerobic training.…”

“…These adaptations include better cardiac contractility that leads to a lower heart rate (HR) at a given submaximal work rate [7,8]. Moreover, modifications in the autonomic nervous system (ANS) activity, which can be determined through the non-invasive monitoring of the resting heart rate variability (HRV), have been associated with training-induced changes in aerobic fitness in both sedentary [9] and trained subjects [9,10].…”

Evaluating cardiovascular dysfunction during increased activity and exercise rehabilitation following incomplete thoracic spinal cord injury in the adult rat.

“…Additionally, endurance training enhances cardiac output, the result of cardiac hypertrophy and improved contraction ability. In turn, this allows for enhanced ventricular filling capacities and the subsequent increase in stroke volume potential (Hellsten and Nyberg 2015). Due to denervation-induced paralysis of the lower extremities, SCI patients are often limited to upper extremity exercise training only.…”

“…Active aerobic exercise modalities have traditionally been preferred over passive rehabilitation for their effects on CV and respiratory systems (Ballaz et al 2008, Hellsten andNyberg 2015). However, denervation-induced paralysis of the trunk and lower limbs in combination with blunted hemodynamic responses to exercise following high thoracic SCI makes this type of rehabilitation difficult in the SCI community (Van Loan et al 1987).…”