Zone 2 cardio — sustained, conversational-pace aerobic exercise — has emerged as the most consistently supported longevity intervention in exercise science. Unlike high-intensity training, Zone 2 specifically targets mitochondrial biogenesis: the creation of new, healthy mitochondria in your muscle cells.
Your mitochondria are the energy factories of every cell. As they decline in number and efficiency with age, so does your metabolic health, cardiovascular function, and cognitive sharpness. Zone 2 training reverses this decline.
How to find your Zone 2: You should be able to hold a full conversation without gasping. On a 1–10 exertion scale, it's a 4–5. For most people over 60, this means a brisk walk, easy cycling, or light swimming — not a jog.
The research prescription: 150–180 minutes per week of Zone 2 training, spread across 3–5 sessions. Stanford's longevity research shows this volume produces the greatest gains in VO2 max — the single strongest predictor of all-cause mortality.
Practical tip: Use a heart rate monitor. Zone 2 for most adults over 60 falls between 100–130 bpm. The Maffetone Method (180 minus your age) gives a reliable upper ceiling for your Zone 2 heart rate.