The microcirculation of skeletal muscle in aging.

Microvascular structure and function are key aspects of tissue and organ health. At approximately 40% of total body mass, skeletal muscle contains more microvessels than any other organ system in the body. Moreover, skeletal muscle is the most dynamic tissue in the body with the capacity to increase blood flow and metabolic rate 30- to 50- fold. Aging is associated with decrements in microvascular function and exercise tolerance that are poorly understood. Here, experts in their respective fields of microvascular structure and function are brought together to review the current state of knowledge regarding microvascular adaptations to aging. Reviews are drawn from human and animal studies and focus on age-related changes in sympathetic nervous system control of microvessels, capillary hemodynamics and oxygen pressure, microvascular network structure and functional integration, microvascular reactivity, whole muscle perfusion, and cellular contacts and inflammation.