Zone 2 Cardio Training
Zone 2 cardio (conversational pace, 60-70% max HR) for 3-4 sessions of 45-60 min/week builds mitochondrial density and is the foundation of metabolic health and longevity.
Dosage & Timing
Evidence Strength
5/5 — Very StrongVery strong evidence. Decades of exercise physiology research confirm Zone 2 training improves mitochondrial density, fat oxidation, and cardiovascular health. Endorsed by Iñigo San Millán and Peter Attia.
Overview
Perform 150-180 minutes per week of Zone 2 cardiovascular exercise — the intensity at which you can maintain a conversation but are breathing noticeably harder than at rest. Zone 2 corresponds to roughly 60-70% of max heart rate. This intensity maximally trains mitochondrial function and fat oxidation, forming the aerobic base that supports all other fitness domains.
How To Do It
Determine your Zone 2
Zone 2 ≈ 60-70% max HR. A practical test: you can hold a conversation but prefer not to. Use the MAF formula (180 - age) as a starting estimate.
Choose your modality
Walking uphill, cycling, rowing, swimming, or elliptical. Choose something sustainable and low-injury-risk.
Start with 3x 30 min
If you're new, begin with three 30-minute sessions per week and build toward 45-60 min sessions.
Stay in zone
Resist the urge to go harder. The benefit is in sustained moderate effort. If you can't talk, slow down.
Progress gradually
Build to 150-180+ min/week over 4-8 weeks. Add duration before frequency.
The Evidence
Each claim is linked to its source study. Confidence reflects the study design — systematic reviews and RCTs rank highest.
Cardiorespiratory fitness as a quantitative predictor of mortality and cardiovascular events↗
Higher cardiorespiratory fitness strongly predicted lower mortality and cardiovascular events.
Primary Literature
Who Popularized This
Interactions & Warnings
Contraindications
- ⚠Uncontrolled cardiovascular disease
- ⚠Severe joint issues (choose low-impact modality)
Interactions
- •Complements high-intensity interval training
- •Supports recovery between strength sessions
Measurable Outcomes
Equipment Needed
- • Heart rate monitor (recommended)
- • Any cardio equipment or outdoor space
Related Protocols
Grip Strength Training
Train grip 2-3x/week with dead hangs, farmer carries, and crush exercises. Grip strength is a top biomarker for longevity and functional independence.
Deload Week
Reduce training volume by 40-60% every 4-6 weeks. Strategic recovery prevents overtraining, reduces injury risk, and enables long-term progress.
VO2 Max Interval Training
4x4 minute intervals at 90-95% max HR, 1-2x/week. VO2 max is the strongest cardiorespiratory fitness marker for longevity. High-intensity intervals are the most efficient way to improve it.
Postmenopause Strength Training
Train major muscle groups 2-3 times per week with progressive loads, enough recovery, and symptom-aware progression. This is a high-value protocol for postmenopausal strength and healthspan.