Heart Rate Zones for Running: A Practical Guide

Heart rate zones divide your effort into ranges, each with a different training effect. Understanding your zones means you can train with purpose — spending the right amount of time at the right intensity, instead of running at the same moderate effort every day and wondering why you're not improving.

The 5 Heart Rate Zones

Most zone models divide heart rate into five zones based on a percentage of your maximum heart rate (max HR). Here's what each zone means and what it does for your running:

Zone 1: Recovery (50-60% of max HR)

Very easy effort. Walking pace or gentle jogging. Used for warm-ups, cool-downs, and active recovery between hard sessions. You should be able to hold a full conversation effortlessly. Almost no aerobic training stimulus at this intensity — the purpose is recovery, not development.

Zone 2: Aerobic Base (60-70% of max HR)

Easy, comfortable effort. You can talk in full sentences. This is the Zone 2 training that everyone talks about. It builds mitochondria, improves fat oxidation, increases capillary density, and strengthens your heart. Most of your weekly running should be here.

Zone 3: Tempo / Moderate (70-80% of max HR)

"Comfortably hard" — you can speak in short sentences but not hold a real conversation. This zone improves aerobic capacity and teaches your body to clear lactate more efficiently. Useful for tempo runs and longer intervals. The risk: spending too much time here creates fatigue without the specific benefits of Zone 2 (base building) or Zone 4+ (VO2max / speed).

Zone 4: Threshold (80-90% of max HR)

Hard effort. You can only manage a few words at a time. This is close to your lactate threshold — the intensity where lactate production starts exceeding your body's ability to clear it. Training here improves your threshold pace, which is one of the strongest predictors of distance running performance.

Zone 5: VO2max / Maximum (90-100% of max HR)

Maximum or near-maximum effort. You can't speak. This is the intensity of hard intervals, sprints, and race finishes. Training here improves your VO2max — the maximum amount of oxygen your body can use. Effective but very fatiguing; small doses go a long way.

How to Calculate Your Zones

Zones are only useful if they're based on your actual maximum heart rate. Here's how to find it:

Method 1: Observed Max HR (Best)

Your true max HR is the highest heart rate you've ever recorded during an all-out effort. Check your watch data from:

• A hard parkrun or race finish
• The last rep of a hill sprint session
• Any maximal effort where you were truly going as hard as possible

This is the most accurate method. Use the highest number you've seen — max HR doesn't change with fitness (it decreases slowly with age, but not with training status).

Method 2: Field Test

After a thorough warm-up, run 3 × 3-minute intervals up a moderate hill at maximum effort, with 2 minutes of easy jogging between. Your peak HR on the last interval is a good estimate of your max HR.

Method 3: 220 Minus Age (Avoid If Possible)

The formula "220 − age" is widely known but notoriously inaccurate. It's a population average with a standard deviation of about 12 bpm. A 40-year-old runner could have a max HR anywhere from 158 to 202 bpm. If your zones are based on a wrong max HR, all your training is calibrated wrong.

Use the 220 formula only as a starting point if you have no observed data. Replace it as soon as you have a real max HR from a hard effort.

Example Zone Calculation

For a runner with an observed max HR of 185 bpm:

How to Use Zones in Your Training

The key insight from decades of research on elite endurance athletes is the polarised distribution: spend most of your time easy (Zone 1-2), some time very hard (Zone 4-5), and very little in the moderate middle (Zone 3).

The 80/20 Rule

Aim for roughly 80% of your weekly training time in Zone 1-2 and 20% in Zone 4-5. In practice, for someone running 5 days a week:

• 3-4 easy runs — all in Zone 1-2
• 1 hard session — intervals or tempo in Zone 4-5
• 1 long run — mostly Zone 2, maybe finishing slightly harder

What About Zone 3?

Zone 3 — the "grey zone" — is where many self-coached runners spend most of their time. It feels like you're working, but it's too easy to build speed and too hard to build your base efficiently. Some Zone 3 is fine (tempo runs, for example), but if most of your running is in Zone 3, you're likely under-training both your aerobic base and your top-end speed.

Common Mistakes with Heart Rate Zone Training

• Using the wrong max HR — the most common problem. If your max HR is wrong, all five zones are wrong. Use observed data, not a formula.
• Ignoring cardiac drift — your heart rate will rise during a run even at a constant effort. A run that starts in Zone 2 might drift into Zone 3. This is normal — learn more in our cardiac drift guide.
• Day-to-day HR variation — stress, sleep, caffeine, heat, and illness all affect heart rate. A "Zone 2 run" in 30-degree heat might have you going very slowly. That's fine — the training effect comes from the physiological stress, not the pace on your watch.
• Wrist HR sensor lag — optical HR sensors on your wrist can lag behind actual heart rate, especially during interval starts and stops. A chest strap is more accurate for zone-based training.
• Never checking your zones — if you set zones once and never look at them, they provide no value. Review your zone distribution weekly to see if you're actually training the way you think you are.

Zone Distribution: Are You Training Right?

One of the most valuable things you can do is look at your weekly zone distribution — how much time you spent in each zone across all your runs. Most runners are surprised to find they spend far less time in Zone 2 and far more in Zone 3 than they thought.

AeroBase calculates your zone distribution automatically from your Garmin heart rate data, using per-second samples for accuracy. You can see at a glance whether your easy runs are actually easy and whether your intensity balance matches the 80/20 target.

Beyond Heart Rate: Other Ways to Gauge Intensity

Heart rate zones are useful but not the only tool. Use them alongside:

• Perceived effort (RPE) — how hard does it feel on a 1-10 scale? Zone 2 should feel like a 3-4.
• Talk test — full sentences = Zone 1-2. Short phrases = Zone 3. A few words = Zone 4. Can't speak = Zone 5.
• Pace — useful for track workouts, less useful for hilly terrain or varied conditions.

When heart rate and perceived effort disagree, trust perceived effort — your HR might be elevated by heat, stress, or poor sleep, but the right training intensity is still the one that feels appropriate for the session's purpose.