Effects of exercise in normobaric hypoxia on hemodynamics during muscle metaboreflex activation in normoxia.

Autor: Mulliri G; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy.; International PhD in Innovation Sciences and Technologies, University of Cagliari, Cagliari, Italy., Sainas G; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Magnani S; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Roberto S; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Ghiani G; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Mannoni M; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Pinna V; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy.; International PhD in Innovation Sciences and Technologies, University of Cagliari, Cagliari, Italy., Willis SJ; Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland., Millet GP; Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland., Doneddu A; Department of Medical Sciences and Public Health, Sports Physiology Lab, University of Cagliari, Via Porcell 4, 09124, Cagliari, Italy., Crisafulli A; Department of Medical Sciences and Public Health, Sports Physiology Lab, 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] 2019 May; Vol. 119 (5), pp. 1137-1148. Date of Electronic Publication: 2019 Feb 19.
DOI: 10.1007/s00421-019-04103-y
Abstrakt: Purpose: Little is known about the cardiovascular effects of the transition from exercise in hypoxia (EH) to normoxia. This investigation aimed to assess hemodynamics during the metaboreflex elicited in normoxia after EH.
Methods: Ten trained athletes (four females and six males, age 35.6 ± 8.4 years) completed a cardiopulmonary test to determine the workload at anaerobic threshold (AT). On separate days, participants performed three randomly assigned exercise sessions (10 min pedalling at 80% of AT): (1) one in normoxia (EN); (2) one in normobaric hypoxia with FiO 2 15.5% (EH15.5%); and (3) one in normobaric hypoxia with FiO 2 13.5% (EH13.5%). After each session, the following protocol was randomly assigned: either (1) post-exercise muscle ischemia after cycling for 3 min, to study the metaboreflex, or (2) a control exercise recovery (CER) session, without any metaboreflex stimulation.
Results: The main result were that both EH15.5% and EH13.5% impaired (p < 0.05) the ventricular filling rate response during the metaboreflex (- 18 ± 32 and - 20 ± 27 ml s -1 ), when compared to EN (+ 29 ± 32 ml s -1 ), thereby causing a reduction in stroke volume response (- 9.1 ± 3.2, - 10.6 ± 8.7, and + 5 ± 5.7 ml for EH15.5%, EH13.5% and EN test, respectively, p < 0.05). Moreover, systemic vascular resistance was increased after the EH15.5% and the EH13.5% in comparison with the EN test.
Conclusions: These data demonstrate that moderate exercise in hypoxia impairs the capacity to enhance venous return during the metaboreflex stimulated in normoxia. Overall, there is a functional shift from a flow to vasoconstriction-mediated mechanism for maintaining the target blood pressure during the metaboreflex.
Databáze: MEDLINE
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