Exercise-Induced Cardiac Fatigue after a 45-Minute Bout of High-Intensity Running Exercise Is Not Altered under Hypoxia

•High-intensity exercise for 45 min induces right- and left-sided cardiac fatigue.•EICF is more pronounced during stress echocardiography.•Exercise under hypoxia does not exaggerate EICF. BackgroundAcute promotes transient exercise-induced fatigue, which affects the right ventricle to a lesser extent left ventricle. Hypoxic exposure an additional increase in ventricular (RV) afterload. Therefore, may differently affect both ventricles. The aim of this study was investigate acute effects bout high-intensity versus normoxia healthy individuals on function mechanics.MethodsTwenty-one (mean age, 22.2 ± 0.6 years; 14 men) performed 45-min running (fraction inspired oxygen 14.5%) 20.9%) randomized order. Pre- post-exercise echocardiography, at rest low-to-moderate intensity recumbent (“stress”), assess RV (LV) mechanics. structure, function, mechanics were assessed using conventional two-dimensional, Doppler, tissue speckle-tracking echocardiographic, novel strain-area loops.ResultsIndices systolic (RV fractional area change, Tricuspid annular plane excursion, s?, free wall strain) LV (LV ejection fraction global longitudinal significantly reduced after (P < .01). These changes when echocardiography examined compared with baseline. responses indices altered > .05).ConclusionsThere no impact magnitude fatigue ventricles exercise. This finding suggests that any potential loading conditions automatically exacerbate setting. Acute Twenty-one loops. Indices .05). There