150+ min Zone 2 cardio weekly

Estimated longevity benefit: +3.3 years. Evidence score: 100/100.

Zone 2 cardio — sustained aerobic exercise at 60–70% of maximum heart rate — is the intensity where fat oxidation peaks, mitochondrial density increases, and cardiovascular adaptations accumulate without excessive recovery cost. VO2 max, the primary adaptation driven by Zone 2 training, is the single strongest modifiable predictor of lifespan identified in large-scale mortality research, with risk reductions that rival or exceed quitting smoking.