A brief bout of exercise in hypoxia reduces ventricular filling rate and stroke volume response during muscle metaboreflex activation.

Autor: Mulliri G; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy.; International PhD in Innovation Sciences and Technologies, University of Cagliari, Cagliari, Italy., Magnani S; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy.; International PhD in Innovation Sciences and Technologies, University of Cagliari, Cagliari, Italy., Roberto S; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Sechi F; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Ghiani G; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Sainas G; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Nughedu G; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Hosseini Kakhak SA; Faculty of Physical Education and Sport Sciences, Hakim Sabzevari University, Sabzevar, Iran., Bassareo PP; University College of Dublin, Mater Misericordiae University Teaching Hospital, Dublin, Ireland., Crisafulli A; Sports Physiology Laboratory, Department of Medical Sciences and Public Health, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy. crisafulli@tiscali.it.; International PhD in Innovation Sciences and Technologies, University of Cagliari, Cagliari, Italy. crisafulli@tiscali.it.
Jazyk: angličtina
Zdroj: European journal of applied physiology [Eur J Appl Physiol] 2020 Sep; Vol. 120 (9), pp. 2115-2126. Date of Electronic Publication: 2020 Jul 19.
DOI: 10.1007/s00421-020-04435-0
Abstrakt: Purpose: The hemodynamic consequences of exercise in hypoxia have not been completely investigated. The present investigation aimed at studying the hemodynamic effects of contemporary normobaric hypoxia and metaboreflex activation.
Methods: Eleven physically active, healthy males (age 32.7 ± 7.2 years) completed a cardiopulmonary test on an electromagnetically braked cycle-ergometer to determine their maximum workload (W max ). On separate days, participants performed two randomly assigned exercise sessions (3 minutes pedalling at 30% of W max ): (1) one in normoxia (NORMO), and (2) one in normobaric hypoxia with FiO 2 set to 13.5% (HYPO). After each session, the following protocol was randomly assigned: either (1) post-exercise muscle ischemia (PEMI) to study the metaboreflex, or (2) a control exercise recovery session, i.e., without metaboreflex activation. Hemodynamics were assessed with impedance cardiography.
Results: The main result was that the HYPO session impaired the ventricular filling rate (measured as stroke volume/diastolic time) response during PEMI versus control condition in comparison to the NORMO test (31.33 ± 68.03 vs. 81.52 ± 49.23 ml·s -1 ,respectively, p = 0.003). This caused a reduction in the stroke volume response (1.45 ± 9.49 vs. 10.68 ± 8.21 ml, p = 0.020). As a consequence, cardiac output response was impaired during the HYPO test.
Conclusions: The present investigation suggests that a brief exercise bout in hypoxia is capable of impairing cardiac filling rate as well as stroke volume during the metaboreflex. These results are in good accordance with recent findings showing that among hemodynamic modulators, ventricular filling is the most sensible variable to hypoxic stimuli.
Databáze: MEDLINE
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