Mitochondrial density

Mitochondrial density refers to the number and volume of mitochondria per unit of muscle tissue. Higher density expands oxidative capacity, allowing more fatty acids and pyruvate to be burned aerobically and improving endurance and metabolic flexibility. Aerobic and Zone 2 training stimulate mitochondrial biogenesis via PGC-1α, while age and inactivity reduce it. Maintaining mitochondrial density is considered central to healthy aging and cardiorespiratory fitness.