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Titolo:
Evidence that a central governor regulates exercise performance during acute hypoxia and hyperoxia
Autore:
Noakes, TD; Peltonen, JE; Rusko, HK;
Indirizzi:
Univ Cape Town, Sports Sci Inst S Africa, Dept Human Biol, Res Unit Exercise Sci & Sports Med, ZA-7725 Newlands, South Africa Univ Cape Town Newlands South Africa ZA-7725 7725 Newlands, South Africa Univ Helsinki, Inst Clin Med, Unit Sports & Exercise Med, FIN-00250 Helsinki, Finland Univ Helsinki Helsinki Finland FIN-00250 ed, FIN-00250 Helsinki, Finland KIHU Res Inst Olymp Sports, FIN-40760 Jyvaskyla, Finland KIHU Res Inst Olymp Sports Jyvaskyla Finland FIN-40760 yvaskyla, Finland
Titolo Testata:
JOURNAL OF EXPERIMENTAL BIOLOGY
fascicolo: 18, volume: 204, anno: 2001,
pagine: 3225 - 3234
SICI:
0022-0949(200109)204:18<3225:ETACGR>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
OPERATION EVEREST-II; MAXIMAL OXYGEN-UPTAKE; BLOOD-FLOW; EXTREME ALTITUDE; CARDIAC-OUTPUT; SEA-LEVEL; CONTEMPORARY VIEWPOINTS; DIFFUSION LIMITATION; SIMULATED ALTITUDE; HYPOBARIC HYPOXIA;
Keywords:
central governor; altitude; cardiac output; hypoxia; hyperoxia; maximal rate of oxygen uptake; muscle recruitment;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
96
Recensione:
Indirizzi per estratti:
Indirizzo: Noakes, TD Univ Cape Town, Sports Sci Inst S Africa, Dept Human Biol, Res Unit Exercise Sci & Sports Med, POB 115, ZA-7725 Newlands, South Africa Univ Cape Town POB 115 Newlands South Africa ZA-7725 th Africa
Citazione:
T.D. Noakes et al., "Evidence that a central governor regulates exercise performance during acute hypoxia and hyperoxia", J EXP BIOL, 204(18), 2001, pp. 3225-3234

Abstract

An enduring hypothesis in exercise physiology holds that a limiting cardiorespiratory function determines maximal exercise performance as a result ofspecific metabolic changes in the exercising skeletal muscle, so-called peripheral fatigue. The origins of this classical hypothesis can be traced towork undertaken by Nobel Laureate A. V. Hill and his colleagues in London between 1923 and 1925. According to their classical model, peripheral fatigue occurs only after the onset of heart fatigue or failure. Thus, correctlyinterpreted, the Hill hypothesis predicts that it is the heart, not the skeletal muscle, that is at risk of anaerobiosis or ischaemia during maximal exercise. To prevent myocardial damage during maximal exercise, Hill proposed the existence of a 'governor' in either the heart or brain to limit heart work when myocardial ischaemia developed. Cardiorespiratory function during maximal exercise at different altitudes or at different oxygen fractionsof inspired air provides a definitive test for the presence of a governor and its function. If skeletal muscle anaerobiosis is the protected variablethen, under conditions in which arterial oxygen content is reduced, maximal exercise should terminate with peak cardiovascular function to ensure maximum delivery of oxygen to the active muscle. In contrast, if the function of the heart or some other oxygen-sensitive organ is to be protected, then peak cardiovascular function will be higher during hyperoxia and reduced during hypoxia compared with normoxia. This paper reviews the evidence that peak cardiovascular function is reduced during maximal exercise in both acute and chronic hypoxia with no evidence for any primary alterations in myocardial function. Since peak skeletal muscle electromyographic activity is also reduced during hypoxia, these data support a model in which a central, neural governor constrains the cardiac output by regulating the mass of skeletal muscle that can be activated during maximal exercise in both acute andchronic hypoxia.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 09:30:22