Zone 2 Cardio: The Most Underrated Longevity Habit

VO2 max is the single strongest predictor of all-cause mortality we have. The most efficient way to build it is not sprinting; it is Zone 2, the low-intensity aerobic work that most people consider too easy to bother with. Iñigo San Millán's data shows Zone 2 is uniquely effective at increasing mitochondrial density. Peter Attia calls it the single most important exercise modality for patients over 40.