Boushel 2013 Int J Biochem Cell Biol
|Boushel RC, Saltin B (2013) Ex vivo measures of muscle mitochondrial capacity reveal quantitative limits of oxygen delivery by the circulation during exercise. Int J Biochem Cell Biol 45:68-75.|
Abstract: Muscle mitochondrial respiratory capacity measured ex vivo provides a physiological reference to assess cellular oxidative capacity as a component in the oxygen cascade in vivo. In this article, the magnitude of muscle blood flow and oxygen uptake during exercise involving a small-to-large fraction of the body mass will be discussed in relation to mitochondrial capacity measured ex vivo. These analyses reveal that as the mass of muscle engaged in exercise increases from one-leg knee extension, to 2-arm cranking, to 2-leg cycling and x-country skiing, the magnitude of blood flow and oxygen delivery decrease. Accordingly, a 2-fold higher oxygen delivery and oxygen uptake per unit muscle mass are seen in vivo during 1-leg exercise compared to 2-leg cycling indicating a significant limitation of the circulation during exercise with a large muscle mass. This analysis also reveals that mitochondrial capacity measured ex vivo underestimates the maximal in vivo oxygen uptake of muscle by up to ∼2-fold. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy.
• Keywords: O2 delivery; Oxidative phosphorylation; Exercise
• O2k-Network Lab: CA Vancouver Boushel RC
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Organism: Human Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue
Regulation: ADP Coupling state: OXPHOS Pathway: N, NS