Work-Out - Zones change everything

Why zones change everything

and why coaches swear by them

There’s a moment almost every runner recognises. You lace up, you start “easy”… and somehow you’re already breathing harder than you planned. Ten minutes later you glance at your watch and think: “This doesn’t feel easy”

But you keep going anyway, because it’s training, and training is supposed to feel like effort… right? Well, that’s how most people train. Not intentionally, not out of stubbornness, just because they don’t have a clear framework.

And that’s exactly why heart rate zones matter.

Not because they’re fancy numbers, not because coaches love graphs. But because zones protect the thing that actually makes you fitter: the right effort, repeated consistently, over time.

The Invisible no-zone Problem

Here’s what happens when you train without zones:

Easy runs drift faster and faster
Hard sessions aren’t hard enough to truly stimulate improvement
Recovery gets compromised
You feel tired more often
Progress slows down, even though you’re training more

Many athletes end up living in the same intensity zone, that “grey area” where you’re working, sweating, and feeling productive… but not building the foundation you need.

It’s common, because it feels like training, but it doesn’t always produce training adaptations, and in endurance sport, it’s not effort that builds progress, but the right dose of that effort. And that is exactly what zones are.

What zones are based on

Zones are built around measurable physiological markers

Together, these values define both your internal load and your external output. Two athletes can run the same pace, but internally, they may be working in completely different zones. That’s why proper zones must be personal.

Generic formulas like “220 minus age” are averages and averages are not coaching.

Inside the Work-Out platform, your zones are calculated from your own data.

HEART RATE ZONES

INTERNAL LOAD

Heart rate zones show you what is happening inside your body when you train. They tell you how much physiological stress your system is under to produce a certain movement. That difference between what you see and what is happening internally is fundamental.

Two athletes can run at exactly the same pace. From the outside, they look identical. Internally, however, one may be comfortably running while the other feels like dying. The mechanical output is the same, the metabolic cost is not. Heart rate zones make that invisible difference visible.

Heart rate is also valuable because it adapts to context. Sleep, stress, dehydration and temperature all affect internal load. On a hot day, your heart rate will rise faster at the same pace. After a poor night of sleep, an easy run may feel harder than expected. Heart rate reflects that shift and helps you adjust accordingly.

Heart rate zones typically range from Zone 1 (very easy) to Zone 5 (maximum effort), and each zone trains a different physiological system:

The key is not that one zone is better than another. The key is that each has a role. When those roles blur, training becomes inefficient. When they are clearly defined, progress becomes measurable.

Calculation

Zones only work if they are personal. That is why Work-Out does not use generic “one-size-fits-all” formulas. Instead, your heart rate and pace zones are calculated from values that reflect your own body and current fitness.

To calculate your heart rate zones, the Work-Out platform uses three simple inputs: your resting heart rate, your maximum heart rate, and your threshold heart rate.

If you’re not sure where to find these values, don’t worry, you can usually get them from your wearable data, recent tests, or with the help of your coach. The important part is that the numbers are yours, not estimated from age.

Pace ZONES

external LOAD

Pace zones are slightly more complex than heart rate zones. Not because they are less useful, but because they require a clear reference point to be accurate.

While heart rate tells you how hard your body is working internally, pace tells you what you are producing externally. It reflects performance, output and real speed.

But pace only makes sense if it is anchored to something meaningful. That anchor is your threshold running pace: the fastest pace you can sustain for roughly 30 to 60 minutes at a controlled, hard effort.

Without that reference, pace zones are just numbers. Just like heart rate zones, pace zones are divided into five intensity ranges. Each zone aligns with a specific training purpose:

The purpose is not to chase speed every day. In fact, most endurance development happens in Zones 1 and 2. Pace zones simply help you see what “easy” and “hard” actually mean in real numbers.

The challenge with pace is context. Hills, wind, surface, heat and fatigue all influence how a pace feels. That is why pace zones work best when combined with heart rate. Heart rate protects your internal load. Pace sharpens your external performance.

Calculation

To calculate your pace zones, the Work-Out platform uses one key value: your threshold running pace.

Once you enter this pace in the Endurance section of the app, Work-Out automatically generates five personalised pace zones in min/km. These zones align with your heart rate structure and evolve as your fitness improves.

If your threshold pace becomes faster, your zones shift accordingly. That means your training always reflects your current capacity.

If you are unsure about your threshold pace, you can determine it through:

Again, the most important rule applies: your zones must be based on your own data.

WHERE TO SET THIS IN THE WORK-OUT APP

You can set everything up in your profile, under the ‘Endurance section’ of the Work-Out app. Enter your values once, then tap ‘Auto Calculate’ and your zones will appear immediately. Here’s what you’ll fill in:

Once your zones are set, you can train with clarity. Your sessions stop being vague (“easy”, “steady”, “hard”) and start becoming intentional (“Zone 2 endurance”, “Zone 4 threshold”, “Zone 1 recovery”).

WHERE TO FIND THESE VALUES

Resting heart rate
Open Garmin Connect.
Tap More (the three dots).
Go to Health Stats.
Select Heart Rate.
In the bottom left corner, you will find your resting heart rate.

Maximum heart rate
Open Garmin Connect.
Tap More (the three dots).
Select Garmin Devices.
Choose your device.
Go to User Profile → Heart Rate & Power Zones → Heart Rate.
At the top, you will find your maximum heart rate.

Threshold heart rate and threshold pace
Open Garmin Connect.
Tap More (the three dots).
Go to Performance Stats.
Select Lactate Threshold (Running).
Here you will find your threshold heart rate and threshold running pace.

Heart Rate Zones
Open the Watch app on your iPhone
Go to Workout
Tap Heart Rate Zones
Select Automatic

View Heart Rate Zones
Open the Fitness app on your iPhone
Go to Workouts
Open a recent workout
Scroll to Heart Rate Zones
Here you will see Zone 1 to Zone 5.

Heart rate zones

Open the Polar Flow app.
Tap the menu icon (three lines) in the top left corner.
Go to Sport Profiles.
Select Running.
Tap Edit.

Here you can view:
Heart Rate Zone Limits
Pace Zone Limits

Every wearable works a little differently. Some devices automatically calculate and display your heart rate or pace zones in their own app. While convenient, these calculations vary by brand and are not always based on your personal test values.

That’s why it’s important to manually enter your correct values in the Work-Out app. This ensures your training zones are calculated accurately and fully aligned with your personal coaching.

For the most accurate zones, we strongly recommend structured testing and guidance from a coach. Personalized testing remains the most reliable way to determine your true training thresholds. If you have any questions about your zones, reach out to your coach for support and clarification.

WHEN to UPDATE YOUR ZONES

Zones are not a one-time setup. As you get fitter, your threshold changes, and that means your zones should change too. A good habit is to review them when:

Small updates keep your training accurate and keep progress moving.

Zones aren’t there to complicate your runs, but to give them purpose. Take a few minutes to set your values in the Work-Out app. Press Auto Calculate. See your zones, understand them.

Then lace up, workout with intention and trust the process.

Good luck, and most importantly, have fun.

Calculate your zones on Apple

Calculate your zones on Android

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