Apple Watch heart rate zones, explained
What the built-in zones do, how to set them, and where a dedicated app adds something.
Recent versions of watchOS show five heart-rate zones inside the Workout app. During a run you can swipe to a zones screen and see which of the five you're in. It's a genuinely useful addition, and for a lot of people it's enough. It helps to know how those zones are worked out — and where their limits are.
How Apple calculates your zones
By default the Watch sets your zones automatically from your personal data, using an estimate of your heart-rate reserve (the span between your resting and maximum heart rate). Because it leans on your resting rate, the automatic zones adapt as your fitness changes. You can also switch to manual and set the boundaries yourself.
How to set them yourself
- On iPhone, open the Watch app → Workout → Heart Rate Zones (the exact path shifts slightly between watchOS versions).
- Choose Automatic, or switch to Manual to type your own boundaries.
- If you go manual, base it on a good maximum-heart-rate number — why 220 − age usually isn't it.
Where the built-in zones stop
None of this is a knock on Apple — it's just the difference between a general feature and a purpose-built one:
- You still have to look. The Watch tells you your zone when you raise your wrist and swipe to it. Mid-stride, or on a treadmill three feet away, that's a lot of looking.
- It won't nudge you back. There's no "hold Zone 2 and tap me when I drift" — with a distinct pattern for too-hard versus too-easy — so the most common mistake, quietly leaving your target zone, goes uncaught.
- It's a Watch feature. Training on iPhone alone with a chest strap sits outside it.
- The method is hidden. Percentage-of-maximum and heart-rate-reserve give different numbers at the same percentage; it's not always clear which you're looking at.
Where a dedicated app fits
A zone-focused app fills exactly those gaps: a whole-screen colour you read at a glance, a wrist tap the instant you drift out of a target zone, spoken zone callouts, iPhone-plus-chest-strap support, and clarity about which calculation method is in play. If you mostly want to glance at a zone now and then, the built-in feature is fine. If holding a zone is the workout, the extra help earns its place.
That's what In The Zone is. Your screen becomes your zone's colour, your watch taps you when you drift, and it works with an Apple Watch or with any Bluetooth chest strap on iPhone alone — always showing which zone method it's using. See what it does →
In The Zone is a training aid, not a medical device. Heart-rate zones are estimates. If something feels wrong while exercising, stop and speak to a doctor.