ABSTRACT
This chapter focuses on the final link of the oxygen cascade that began with the inspiration of air, the diffusion of oxygen from the peripheral capillaries to the mitochondria, and its subsequent utilization by these organelles. This link is particularly important in skeletal muscle, which represents more than 40% of our body weight, is heavily relied upon for the performance of physical activity following ascent to high altitude, and is involved in many other important physiological functions including glucose homeostasis regulation. All of the changes in peripheral tissue are intimately influenced by the extent of exercise training or detraining while at high altitude. For example, exercise training at sea level increases muscle capillarity including both the capillary/fiber ratio and number of capillaries per square millimeter within several weeks. The chapter discusses the idea that muscle atrophy might in fact be part of the beginning of an adaptive process since native populations at high altitude also present smaller myofibers.
