Effect of high-altitude exposure on skeletal muscle mitochondrial subcellular distribution, ultrastructure, and respiration in sea-level residents

Skeletal muscle mitochondrial networks may adapt to high altitude by improving respiratory efficiency. We show that despite an increased mitochondrial volume density following a 28-day sojourn at 3,454 m, the surface area of the infoldings of the inner mitochondrial membrane (cristae) decreased within the muscle fiber due to a decline in the mitochondrial cristae density. However, respiration per cristae surface area increased following 7 and 28 days, suggesting intrinsic adjustments.