Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/6519
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dc.contributor.authorGonzález-Alonso, J.-
dc.contributor.authorCalbet, JAL-
dc.contributor.otherCalbet, Jose A
dc.date.accessioned2011-10-26T02:31:00Z-
dc.date.accessioned2018-03-08T13:11:38Z-
dc.date.available2011-10-26T13:16:52Z-
dc.date.available2018-03-08T13:11:38Z-
dc.date.issued2003-
dc.identifier.issn0009-7322-
dc.identifier.urihttp://hdl.handle.net/10553/6519-
dc.description.abstractBACKGROUND: A classic, unresolved physiological question is whether central cardiorespiratory and/or local skeletal muscle circulatory factors limit maximal aerobic capacity (VO2max) in humans. Severe heat stress drastically reduces VO2max, but the mechanisms have never been studied. METHODS AND RESULTS: To determine the main contributing factor that limits VO2max with and without heat stress, we measured hemodynamics in 8 healthy males performing intense upright cycling exercise until exhaustion starting with either high or normal skin and core temperatures (+10 degrees C and +1 degrees C). Heat stress reduced VO2max, 2-legged VO2, and time to fatigue by 0.4+/-0.1 L/min (8%), 0.5+/-0.2 L/min (11%), and 2.2+/-0.4 minutes (28%), respectively (all P<0.05), despite heart rate and core temperature reaching similar peak values. However, before exhaustion in both heat stress and normal conditions, cardiac output, leg blood flow, mean arterial pressure, and systemic and leg O2 delivery declined significantly (all 5% to 11%, P<0.05), yet arterial O2 content and leg vascular conductance remained unchanged. Despite increasing leg O2 extraction, leg VO2 declined 5% to 6% before exhaustion in both heat stress and normal conditions, accompanied by enhanced muscle lactate accumulation and ATP and creatine phosphate hydrolysis. CONCLUSIONS: These results demonstrate that in trained humans, severe heat stress reduces VO2max by accelerating the declines in cardiac output and mean arterial pressure that lead to decrements in exercising muscle blood flow, O2 delivery, and O2 uptake. Furthermore, the impaired systemic and skeletal muscle aerobic capacity that precedes fatigue with or without heat stress is largely related to the failure of the heart to maintain cardiac output and O2 delivery to locomotive muscle.es
dc.languageenges
dc.relation.ispartofCirculation (New York, N.Y.)es-ES
dc.sourceCirculation[ISSN 0009-7322],v. 107 (6), p. 824-830es
dc.subject241106 Fisiología del ejercicioes
dc.subject.otherCardiac outputes
dc.subject.otherExercisees
dc.subject.otherFatiguees
dc.titleReductions in systemic and skeletal muscle blood flow and oxygen delivery limit maximal aerobic capacity in humanses
dc.typeinfo:eu-repo/semantics/Articlees
dc.typeinfo:eu-repo/semantics/Articlees
dc.typeArticlees
dc.identifier.doi10.1161/01.CIR.0000049746.29175.3F
dc.identifier.scopus0037448790-
dc.identifier.isi000181298600010
dcterms.isPartOfCirculation
dcterms.sourceCirculation[ISSN 0009-7322],v. 107 (6), p. 824-830
dc.contributor.authorscopusid7004397216
dc.contributor.authorscopusid7004323423
dc.identifier.absysnet641228-
dc.identifier.crisid475-
dc.identifier.eissn1524-4539-
dc.description.lastpage830
dc.description.firstpage824
dc.relation.volume107
dc.investigacionCiencias de la Saludes
dc.rights.accessrightsinfo:eu-repo/semantics/openAccesses
dc.type2Artículoes
dc.identifier.wosWOS:000181298600010-
dc.contributor.daisngid326233
dc.contributor.daisngid9620399
dc.contributor.daisngid90295
dc.identifier.investigatorRIDH-6693-2015
dc.contributor.wosstandardWOS:Gonzalez-Alonso, J
dc.contributor.wosstandardWOS:Calbet, JAL
dc.date.coverdateFebrero 2003
item.grantfulltextopen-
item.fulltextCon texto completo-
crisitem.author.deptDepartamento de Educación Física-
crisitem.author.deptRendimiento humano, ejercicio físico y salud-
crisitem.author.deptIU de Investigaciones Biomédicas y Sanitarias-
crisitem.author.orcid0000-0002-9215-6234-
crisitem.author.parentorgIU de Investigaciones Biomédicas y Sanitarias-
crisitem.author.fullNameLópez Calbet, José Antonio-
crisitem.author.departamentoEducación Física-
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Reductions in systemic and skeletal muscle blood flow and oxygen delivery limit maximal aerobic capacity in humans
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