adrenergic signaling is impaired in hypertensive cardiomyocytes via GRK2 (red arrows). Exercise training attenuates GRK2 and calcineurin abundance in hypertension (green arrows) thereby allowing greater phosphorylation of PKA targets (green ⁺) such as phospholamban (PLB), ryanodine receptor (RyR), and the L-type channel leading to improved systolic and diastolic functions during stress and exertion. Exercise also alters the agonist binding affinity for βAR receptors (green arrows). SR: sarcoplasmic reticulum; AC: adenylyl cyclase; NOS: nitric oxide synthase; Gs: G stimulatory protein; Gi: G inhibitory protein.