Beyond Zone 2

I have talked a lot about Zone 2 training, and for good reason. It’s the foundation of aerobic fitness, metabolic health, and longevity. But there’s a bigger picture. Heart rate training doesn’t stop at Zone 2. The other zones, 1, 3, 4, and 5, each serve a unique purpose and, when used correctly, can supercharge your fitness.

If Zone 2 is the reliable workhorse, think of the other zones as tools in a performance toolbox. Whether you're chasing better recovery, top-end speed, or a stronger threshold, understanding the full spectrum of training zones allows you to train smarter, not just harder.

Let’s break them down and learn how to find them.

How to Find Your Heart Rate Zones (the Right Way)

Forget the old-school "220 minus age" formula. It’s too simplistic and often wrong, especially for trained individuals. Instead, use one of these methods:

1. Lab Testing (Gold Standard)

• Lactate Threshold Testing or VO2 Max Testing at a sports science lab will give you precise zone breakpoints.

• Expensive, but highly accurate.

2. Field Testing (Reliable + Accessible)

• Maximum Heart Rate Field Test:

  • Warm up, then run or row hard for 2-3 minutes, rest briefly, then go even harder for another 2 minutes. The peak HR at the end is close to your actual max. Running works the best for this one.

• Threshold HR Test:

  • Perform a 30-minute time trial at your best sustainable pace.

  • Record your average HR for the last 20 minutes; that’s your Lactate Threshold Heart Rate (LTHR).

  • Use this to define training zones (see below).

3. Wearables + Apps

• Tools like Garmin, Whoop, or Polar estimate zones based on collected data over time.

• Not perfect, but helpful, especially when paired with perceived effort.

Now, onto the zones.

Zone 1: The Underestimated Recovery Zone

How it feels: Very easy, nose breathing only, completely conversational
Target HR: Below 85% of your aerobic threshold (or below ~65–70% of LTHR)

Zone 1 is often dismissed as “too easy to matter.” But that’s a mistake. Light movement, like a walk, slow spin, or easy row, has been shown to accelerate recovery by promoting circulation, reducing soreness, and rebalancing the nervous system.

Zone 1 stimulates the parasympathetic nervous system and supports mitochondrial repair after intense sessions. Elite athletes use this zone frequently between hard workouts.

Zone 2: The Base Builder (Quick Recap)

How it feels: Easy, you can talk in complete sentences
Target HR: Between the aerobic threshold and ~5–10 bpm below your lactate threshold
Field method: When you can breathe through your nose but feel like you're working just enough that long-term effort is sustainable

Zone 2 builds your aerobic engine. It increases mitochondrial density, improves fat oxidation, and enhances metabolic flexibility, all with minimal stress. For most people, Zone 2 should make up the bulk of endurance and health-focused training.

Zone 3: The Misunderstood Middle

How it feels: Moderate, you can talk but prefer not to
Target HR: Just below and up to your lactate threshold
Field method: A pace you could hold for 45–60 minutes, but not much longer

Zone 3 has long been labeled the “gray zone”: not easy enough for recovery, not hard enough for big breakthroughs. But that thinking is changing.

Newer studies show Zone 3 improves lactate clearance and builds aerobic endurance under fatigue, especially useful for events with prolonged effort. It mirrors the pacing found in sports like Hyrox, CrossFit metcons, and tempo-style running or rowing.

Use Zone 3 sparingly unless training specifically for sustained efforts.

Zone 4: The Threshold Zone

How it feels: Hard, breathing is deep and rhythmic, only short phrases are possible
Target HR: From your lactate threshold up to ~95% of max HR
Field method: Best pace or effort you could sustain for ~30–40 minutes max

Zone 4 is where adaptation kicks in. It improves VO2 max, raises your lactate threshold, and strengthens your cardiac output by pushing stroke volume to the max.

A classic Zone 4 workout is the 4x4 method: 4 minutes hard, 3 minutes recovery, repeated four times. This protocol has strong evidence for boosting aerobic power and is a time-efficient way to get results.

Zone 5: The Red Line

How it feels: All-out breathing is rapid and uncontrolled, and talking is impossible
Target HR: Near or at your true max heart rate
Field method: 20–60 second sprints with long rest, repeated 4–8 times

Zone 5 is for speed, explosiveness, and anaerobic capacity. It taps into the phosphocreatine and glycolytic systems, not just aerobic. Use it sparingly, 1 to 2 times per week, and make sure you’re well recovered before and after.

Short bursts of Zone 5 work have been shown to stimulate mitochondrial growth and enhance your “speed reserve,” even for endurance athletes.

Putting It All Together: A Smart Zone Strategy

You don’t need to train in all five zones every week. But knowing what each zone does helps you structure your week or season intentionally.

The three most common programming models:

• Polarized Training (great for most people)

  • ~80% in Zones 1–2

  • ~20% in Zones 4–5

  • Zone 3 is used sparingly, and is often avoided

• Pyramidal Training (for long-distance athletes)

  • Majority in Zone 2

  • Some in Zone 3

  • Small amounts in Zones 4–5

• Threshold-Focused (for sport-specific prep)

  • Emphasis on Zone 3

  • Useful for races or activities requiring sustained high effort

  • Requires careful monitoring to avoid overtraining

Final Thought: Don’t Guess—Test

If you’re serious about training, take the time to identify your true lactate threshold and aerobic base using a field test or a wearable platform that adapts with your performance. From there, build a weekly plan that includes easy base work, intentional high-effort intervals, and the recovery work to support it all.

Training by zones isn't just about tracking heartbeats—it’s about training with purpose, optimizing recovery, and getting better with every session.

See you in the Gym!