Zone 2 cardio: the boring habit that adds years
Peter Attia, Iñigo San Millán and most longevity-focused clinicians point to Zone 2 as the highest-leverage piece of cardio you can do.
What is Zone 2?
Zone 2 is the intensity at which your body burns fat efficiently while keeping lactate production low. Practically: you can hold a conversation but not sing. Heart rate roughly 60–70% of your max.
It builds mitochondrial density — the cellular engines that convert oxygen into energy. More mitochondria = better metabolic health, lower heart-disease risk, better cognitive aging.
How much is enough?
- Three to four sessions of 45–60 minutes per week.
- Walking briskly uphill, easy cycling, slow jogging — anything that keeps you in the conversational pace.
- Skip the high-intensity ego trips for now. Build the aerobic base first.
Why most people skip it
It feels too easy. That's the trap. The body adapts most when you stay just below your anaerobic threshold for long stretches — not when you go all-out for 20 minutes.
Open Vitality, look at your weekly steps and resting heart rate. Trends moving in the right direction? Zone 2 is doing its job.