The One Thing We Don’t Do at Suffer City

And How You Can Use It for Your Next Breakthrough

Suffer City’s training program is almost a fully complete system.

Strength is your foundation — developing stability, durability, and resilience from the ground up.
Aerobics builds your base of oxygen utilization, improving lactate response and air-gas exchange.
Speed & Power advances run speed, work tempo, and power output.
Engine integrates all aspects of fitness into a single course of work to pressure-check total performance.

If you train consistently across these classes, your fitness will improve.

But there is still one critical component of health, fitness, and longevity that we intentionally do not program inside our group classes.

And ironically, it may be one of the most powerful tools available for improving performance, metabolic health, recovery capacity, and long-term wellbeing.

That component is Zone 2 training.

What Is Zone 2 Training?

Zone 2 is steady-state, low-intensity, long-duration aerobic exercise.

Steady-state means the work is continuous — no intervals, no stops, no spikes. Low-intensity refers to how hard the effort feels. Long-duration means long enough for deeper metabolic and physiological systems to activate. I generally prescribe 50 to 90 minutes.

This type of training is widely endorsed across endurance sports, medicine, and longevity research. Physicians and performance scientists consistently point to Zone 2 as one of the most effective ways to improve cardiovascular health, metabolic efficiency, and mitochondrial function.

Dr. Iñigo San Millán, a leading researcher in endurance physiology, often refers to Zone 2 as the “FatMax” zone — the intensity at which fat oxidation is maximized and aerobic machinery is trained most effectively.

Why It’s Called “Zone 2”

Zone 2 isn’t just a feeling, nor is it your heart rate zone — it’s a physiological state defined by several metrics aligning at once.

When you’re truly in Zone 2:

• Heart rate sits in a specific range

• Breathing is heavy but controlled

• Perceived exertion feels “workable”

• Blood lactate remains low and stable

Approximate markers for most people:

• RPE: 3–4 out of 10 (err toward a 5 rather than a 2)

• Heart Rate: ~70–80% of max (individualized)

• Respiratory Rate: ~18–24 breaths per minute

• Blood Lactate: ~1.8–2.2 mmol/L

This is the intensity where you can sustain effort for a long time without drifting upward into harder zones.

You are working — but it's sustainable and you're not "hurting" -- you're in control.

What’s Actually Happening in the Body

Zone 2 training improves how efficiently your body:

• Consumes oxygen in high volume

• Uses fat as fuel

• Clears lactate

• Expels carbon dioxide

• Recovers between harder sessions

This happens through adaptations such as:

• Increased mitochondrial density and function

• Improved fat oxidation at submaximal workloads

• Better capillary perfusion to muscle tissue

• Enhanced cardiac efficiency (stroke volume)

Oxygen is the key molecule for life. It fuels energy production, tissue repair, immune function, and neurological health. When your aerobic system improves, everything else becomes easier.

Hard workouts feel more manageable. Recovery accelerates. Daily energy stabilizes.

How to Use Zone 2 with Suffer City Training

Zone 2 works best in addition to your existing schedule — not as a replacement.

Guidelines:

• 1–3 sessions per week

• 50–90 minutes per session

• Use running, fast walking, cycling, rowing, skiing — any low-resolution movement

• Keep effort steady and controlled

If you train hard in the morning, add Zone 2 later in the day. If you train in the evening, add Zone 2 on mornings you otherwise wouldn’t train.

This spacing allows Zone 2 to enhance recovery without interfering with high-intensity adaptation.

What to Expect If You Commit

If you apply Zone 2 consistently:

• Energy levels rise

• Sleep improves

• Recovery accelerates

• Hard workouts feel more efficient

• Aerobic capacity expands

• Fat metabolism improves

This isn’t flashy training. It’s foundational training.

And when layered properly with Strength, Aerobics, Speed & Power, and Engine, it becomes the missing link that allows everything else to work better — longer.

Train hard. Recover intelligently. Build capacity that lasts.

That’s the point.