Zone 2 Aerobic Training — Exercise & Movement
Low-intensity steady-state cardio targeting mitochondrial fat oxidation capacity, considered the cornerstone of Peter Attia's longevity exercise prescription.
Overview
Zone 2 training is defined as exercise performed at the highest intensity where lactate remains below 2 mmol/L, typically 60-70% of VO2 max or where one can maintain a conversation but with some effort. This intensity uniquely targets mitochondrial biogenesis and fat oxidation capacity in type I muscle fibers. The HUNT study (n=55,000+) and extensive work by Iñigo San-Millán demonstrate that mitochondrial dysfunction in zone 2 is a hallmark of metabolic disease and that consistent zone 2 training reverses this dysfunction. Peter Attia considers zone 2 the single most important exercise modality for longevity, prescribing 3-4 hours per week.
Indications
- Mitochondrial biogenesis and function
- Fat oxidation and metabolic flexibility
- Cardiovascular health and endurance base
- Insulin sensitivity improvement
- Lactate clearance capacity
- All-cause mortality risk reduction
Mechanism of Action
Zone 2 intensity activates PGC-1α via AMPK signaling, stimulating creation of new mitochondria in type I muscle fibers
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Zone 2 Cardio | 45-60 min per session | 3-4x/week (180-240 min total) | Heart rate at 60-70% max or RPE 3-4/10 |
| Zone 2 Cardio (Beginner) | 20-30 min per session | 3x/week | Build to 45+ min over 4-8 weeks |
Safety & Contraindications
- Very low injury risk; appropriate for nearly all fitness levels
- Start with shorter sessions (20-30 min) if sedentary
- Monitor heart rate to avoid exceeding zone 2 threshold
- Individuals on beta-blockers may need RPE-based intensity guidance rather than heart rate
- Ensure adequate hydration during longer sessions