O_2 uptake kinetics, pyruvate dehydrogenase activity, and muscle deoxygenation in young and older adults during the transition to moderate-intensity exercise

摘要

In healthy older adults, the adaptation of Vo2P (and presumably muscle O2 consumption) is slowed during the transition to exercise (1, 6, 12, 16). However, what has not been established is whether this slower response is a result of control imposed by impaired O2 delivery or metabolic inertia. There is evidence that muscle O2 delivery is attenuated in the older adult and may contribute to slower Vo2P kinetics [i.e., lower heart rate and/or slower heart rate kinetics (12, 16, 17, 42), lower steady-state limb blood flow (18, 34, 35), and indications of impaired local microvascular flow in both animals (5, 16, 30, 34, 40) and humans (16, 34)].