How to Train Your Cardiovascular Fitness | Peter Attia

Cardiorespiratory fitness optimization relies on maximizing the area of a triangle defined by a Zone 2 base and a VO2 max peak. Elite athletes and general populations alike benefit from an 80-20 training distribution, where the vast majority of volume focuses on Zone 2 to build mitochondrial efficiency. While heart rate is a common metric, it often fails to capture true steady-state physiological demands; lactate or RPE provide more accurate indicators. VO2 max training, ideally performed in three-to-eight-minute intervals, complements this base by pushing oxidative phosphorylation to its limit. Practical implementation requires consistent, steady-state modalities like cycling, rowing, or incline walking, structured to allow for adequate recovery between high-intensity efforts. Maintaining this balance ensures long-term metabolic health and performance, regardless of individual time constraints or specific athletic goals.