1,721,119 research outputs found
Oxygen uptake kinetics: old and recent lessons from experiments on isolated muscle in situ
No full textRegulation of oxygen consumption at exercise onset: Is it really controversial?
Full text linkThe conflicting hypotheses on the limiting factors for skeletal muscle Vo2 on-kinetics might be reconciled in a unifying scenario. Under "normal" conditions, during transitions to moderate-intensity exercise, the limiting factor appears to be an inertia of oxidative metabolism. During transitions to exercise of higher metabolic intensity, O2 delivery could play a relatively minor but significant role as a limiting factor
Skeletal muscle VO2 on-kinetics: set by O2 delivery or by O2 utilization? New insights into an old issue
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Time-delayed phases of V’O2 kinetics: evidences from an animal model and functional relevance
No full textDelayed metabolic activation of oxidative phosphorylation in skeletal muscle at exercise onset
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Oxygen uptake kinetics: why are they so slow? And what do they tell us?
No full textV̇O2 kinetics and O2 deficit are important determinants of exercise tolerance. In "normal" conditions convective and diffusive O2 delivery to skeletal muscle fibers do not represent important determinants of V̇O2 kinetics, whose limiting factors seem mainly located within muscle fibers. Whereas a limiting role by PDH has not been confirmed, the role of inhibition of mitochondrial respiration by NO needs further investigations. Important determinants of skeletal muscle V̇O 2 kinetics likely reside in the interplay between bioenergetic mechanisms at exercise onset. By acting as high-capacitance energy buffers, PCr hydrolysis and anaerobic glycolysis would delay or attenuate the increase in [ADP] within muscle fibers following rapid increases in ATP demand, preventing a more rapid activation of oxidative phosphorylation. The different "localization" of the main limiting factors for V̇O2 kinetics and V̇O2max offers the opportunity to perform a functional evaluation of oxidative metabolism at two different levels of the pathway for O2, from ambient air to mitochondria. Whereas V̇O2max is mainly limited by the capacity of the cardiovascular system to deliver O2 to exercising muscles, by analysis of V̇O2 kinetics the functional evaluation is mainly related to skeletal muscle. In pathological conditions the situation may be less clear, and warrants further investigations
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