THE EFFECT OF ACUTE NORMOBARIC HYPOXIA ON LEFT VENTRICULAR FUNCTION DURING MODERATE INTENSITY EXERCISE
Cardiff Metropolitan University
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Acute normobaric hypoxia is a potent stimuli of cardiac response. At rest, hypoxia induces tachycardia and increases stroke volume (SV) alongside left ventricular (LV) twist and untwist. During moderate exercise hypoxia increases basal and apical circumferential strain rates. It is unknown whether LV twist mechanics are altered by hypoxia during moderate intensity exercise. To test this hypothesis 18 healthy young males performed incremental supine cycling up to 40% of peak power (PP) exercise intensity at normoxic and hypoxic condtions. 2-dimesional speckle tracking derived data showed a small but insignificant increase in LV twist and untwisting velocity in hypoxia. Basal (p<0.0001) and apical (p<0.0001) circumferential strain rates and heart rate increased in normobaric hypoxia. In conclusion by significantly increasing heart rate and contractility acute normobaric is a potent stimuli of cardiac response. However hypoxia has minimal effect of LV twist function at 40% of PP.
DEGREE OF BACHELOR OF SCIENCE (HONOURS) INTERCALATED SPORT AND EXERCISE SCIENCE
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Rigby, James Patrick Clark (Cardiff Metropolitan University, 2016)Substrate metabolism fluctuates at rest and during exercise, with further changes as exercise intensity increases. During hypoxia, the reduction in available oxygen (O2) will cause further alterations to substrate metabolism ...
Hypoxia, not pulmonary vascular pressure induces blood flow through intrapulmonary arteriovenous anastomoses Tremblay, Joshua; Lovering, Andrew T.; Ainslie, Philip; Stembridge, Mike; Burgess, Keith R.; Bakker, Akke; Donnelly, Joseph; Lucas, Samuel J.E.; Lewis, Nia C. S.; Dominelli, Paolo B.; Henderson, William R.; Dominelli, Giulio S.; Sheel, A. William; Foster, Glen (The Physiological Society, 2014-12-23)Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased with exposure to acute hypoxia and has been associated with pulmonary artery systolic pressure (PASP). We aimed to determine the direct ...
Impaired myocardial function does not explain reduced left ventricular filling and stroke volume at rest or during exercise at high altitude Stembridge, Mike; Ainslie, Philip; Hughes, Michael G.; Stöhr, Eric J.; Cotter, James D.; Tymko, Michael M.; Day, Trevor A.; Bakker, Akke; Shave, Rob (American Physiological Society, 2015-11-15)Impaired myocardial systolic contraction and diastolic relaxation have been suggested as possible mechanisms contributing to the decreased stroke volume (SV) observed at high altitude (HA). To determine whether intrinsic ...