Acute exposure to cold air and metabolic responses to exercise

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Bibliographische Detailangaben
Deutscher übersetzter Titel:Akute Kaelteexposition und Reaktionen des Energiestoffwechsels
Autor:Therminarias, A.
Erschienen in:International journal of sports medicine
Veröffentlicht:13 (1992), Suppl.1, S. S187-S190, Lit.
Format: Literatur (SPOLIT)
Publikationstyp: Zeitschriftenartikel
Medienart: Gedruckte Ressource
Sprache:Englisch
ISSN:0172-4622, 1439-3964
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Erfassungsnummer:PU199309061987
Quelle:BISp

Abstract

Acute exposure of the whole body to cold air activates thermoregulatory mechanisms which may influence the physiological responses to exercise. Interactions between cold stress and exercise greatly depend on the intensity of cold stimulation. During exposure to moderate cold (MC) peripheral vasoconstriction shifts part of the blood from the periphery to the core, increasing the central volume and the ventricular filling. When an incremental exercise is performed in MC, the persistence of cutaneous vasoconstriction alters the cardiovascular pattern. Moreover, a delayed onset of the increase in plasma lactate concentration (LA) is found and LA remains lower for submaximum exercise intensities. Simultaneously a greater plasma norepinephrine (NA) response is observed. In addition to cutaneous vasoconstriction shivering thermogenesis occurs during exposure to severe cold (SC) which increases heat production. During incremental exercise, the VO2 and the expired minute ventilation (VE) are higher for each exercise intensity. However the ventilatory equivalent (VCO2/VO2) does not change significantly. The increased ventilatory response seems to remain a pure reaction to increasing metabolic demand. The ventilatory threshold occurs at the same exercise intensity but at a higher VO2 and VE than in warm conditions. According to the intensity of cold stress the VO2 level may be similar, increased or decreased at exhaustion. The LA is higher for light exercise intensities, lower for heavy exercise intensities and recovery. Verf.-Referat (gekuerzt)