Geert Kleinnibbelink

Summary 11 225 resulted in adaptations in RV mechanics, with less uncoupling and lessening of the systolic and diastolic slopes of the RV strain-area loop. Second, we found that pre-training augmentation in RV fractional area change to acute hypoxic exercise was inversely related to cardiac remodelling of the RV following 12 weeks of hypoxic endurance training in healthy individuals. Taken together, our results demonstrate that acute cardiac responses of the RV to hypoxic exercise are related to subsequent RV remodelling upon 12-weeks of hypoxic exercise training in healthy, relatively untrained individuals. In Chapter 4 , we evaluated the impact of an increase inTraining volume (across 9-months) in elite rowers on left- and right-sided cardiac structure, function and mechanics. We showed that an increase training volume in elite rowers across 9-months resulted in significant structural adaptation of the left ventricle and atrium, with no adaptations observed on the right side. Left-sided structural cardiac adaptation was accompanied by an increase in LV twist, but no other left- or right-sided functional adaptations. This highlights the plasticity of the heart for remodelling in response to exercise training, even in elite athletes. The finding that left-sided cardiac remodelling was found in elite athletes across 9-months training, and the observation from Chapter 3 that right-sided remodelling is present in untrained individuals, suggests a time-dependent adaptation of the heart to exercise training (see Chapter 10 ). In Chapter 5 , we investigated the impact of hypoxia on PEH, and whether the magnitude of PEH relates to the BP-lowering effect of 12-week hypoxic endurance exercise-training. We demonstrated that the magnitude of PEH does not differ when exercise, matched at relative intensity, is performed under hypoxia or normoxia. The magnitude of PEH during the first exercise bout was positively related to the magnitude of the BP-lowering effect of 12-weeks high-intensity running exercise training under hypoxia. Taken together, our results demonstrate that hypoxia does not alter the PEH response, whilst we reveal the close relationship between acute and chronic changes in BP in response to high-intensity running exercise in healthy individuals.