The Reason VO₂ Max Declines with Age (gethealthspan.com)

The article explains that VO₂ max declines with age not only because the heart delivers less oxygen, but increasingly because muscles lose the ability to extract and use it efficiently. It quantifies that maximal cardiac output drops less than VO₂ max, shifting a larger share of the limitation to peripheral factors like mitochondrial changes, reduced capillaries, and sarcopenia. It argues these peripheral systems can still adapt—endurance training supports capillary growth, while HIIT/SIT can drive mitochondrial improvements efficiently—so long-term consistency in aerobic training matters.