Zone 2 Cardio why it matters, and how to easily implement it

To understand why Zone 2 is so powerful, it helps to know how your body actually makes energy and how this connects to the food you eat and your everyday energy.  Your body has two main energy systems that switch on depending on how hard you’re working: Aerobic vs Anaerobic.

Aerobic exercise is a low-intensity, long-duration activity that uses oxygen to produce energy, while anaerobic exercise is a high-intensity, short-burst activity that generates energy without oxygen. The main difference is the use of oxygen: aerobic means “with oxygen,” and anaerobic means “without oxygen”. Examples of aerobic exercise include jogging or cycling, and examples of anaerobic exercise include sprinting or weightlifting.

The Aerobic System: Your “Long-Life Engine” vs. The Anaerobic System: “Your Quick-Power Engine”

Aerobic
Anaerobic
Oxygen use
Uses oxygen to create energy
Does not use oxygen to create energy
Energy source
Primarily uses carbohydrates, fats, and proteins
Primarily uses stored glucose
Duration
Long-duration, steady-state activities
Short-duration, high-intensity bursts
Examples
Jogging, cycling, walking, swimming, elliptical trainers
Sprinting, weightlifting, jump squats, high-intensity interval training (HIIT)
Benefit
Increases endurance and cardiovascular health
Improves strength and power
By-product
Releases carbon dioxide and water
Produces lactic acid (causing the “burning” sensation)

Zone 2 Cardio is Your Aerobic System

When you train in Zone 2, you’re working primarily with your aerobic energy system, the pathway your body uses to produce energy with oxygen. This is the system that supports sustained, steady effort over longer periods, whether it’s a long walk, a bike ride, or a light jog. Peter Attia describes Zone 2 cardio as a moderate-intensity aerobic exercise crucial for longevity and metabolic health, defined specifically as the highest metabolic output a person can sustain while keeping their blood lactate levels below 2 millimoles per liter. This effort level primarily stimulates mitochondrial function and fat oxidation.

How to Estimate Your Zone 2
Step 1: Calculate Max Heart Rate: Max HR ≈ 220 – your age

✅ Example: Age 50 → 220 – 50 = 170 bpm (maximum heart rate)

Step 2: Find Your Zone 2 Range: Zone 2 is typically 65–75% of Max HR
Lower end: 170 × 0.65 ≈ 111 bpm
Upper end: 170 × 0.75 ≈ 128 bpm

✅ Example: A 50-year-old, Zone 2 heart rate is roughly 111–128 bpm.

Step 3: Check How It Feels (Talk Test)

  • You can speak in full sentences.
  • Breathing is deeper than rest but still comfortable.
  • You could maintain this effort for 20–60 minutes without exhaustion.

How to Implement Zone 2: In the Studio

  • Stationary bike, light-to-moderate effort.
  • Reformer sessions with continuous, steady effort
  • Low-impact cardio days focused on aerobic efficiency

How to Implement Zone 2: Outdoors

  • Brisk walking
  • Light cycling
  • Easy jogging
  • Up to 50 minutes, 2–3 times per week, but start with 10-15min