Heart Rate Zones Explained: A Plain-English Guide
You bought the smartwatch, it beeps at you about “zone 4” halfway up Highgate Hill, and you have no idea whether that is good or bad. Most parents I coach in Archway have the same question: what do the numbers actually mean, and do I need to care? This is my plain-English guide to heart rate zones, how to work out rough numbers for yourself, and when it is simpler to ignore the watch and use the talk test instead.
Short answer: zones are a useful map, not a rule book. For a busy parent who trains two or three times a week, a rough idea of easy, moderate and hard is enough to make real progress.
What heart rate zones actually are
Your heart rate rises as you work harder. Heart rate zones simply split that range, from resting to flat out, into bands. Each band roughly matches a type of effort and a type of training benefit. Most watches use five zones based on a percentage of your maximum heart rate:
| Zone | % of max heart rate | How it feels |
|---|---|---|
| Zone 1 | 50 to 60% | Very easy. A stroll with the buggy. |
| Zone 2 | 60 to 70% | Easy but purposeful. You can chat in full sentences. |
| Zone 3 | 70 to 80% | Moderate to steady. Talking in shorter sentences. |
| Zone 4 | 80 to 90% | Hard. A few words at a time. |
| Zone 5 | 90 to 100% | All out. You can only keep it up for seconds. |
How to estimate your heart rate zones
The quickest method is the old formula: 220 minus your age gives a rough maximum heart rate. If you are 40, that is about 180 beats per minute. Zone 2 would then be roughly 108 to 126, and zone 4 roughly 144 to 162.
Be honest with yourself about what this is: an estimate. Real maximum heart rates vary a lot between people of the same age, sometimes by 10 to 20 beats either way.
A slightly better method, if you have a resting heart rate from your watch, is the heart rate reserve approach:
- Take your estimated max (220 minus age).
- Subtract your resting heart rate (measured first thing in the morning, sitting quietly). That gap is your reserve.
- Multiply the reserve by the zone percentage, then add your resting heart rate back on.
Example: a 40-year-old with a resting heart rate of 60. Reserve is 180 minus 60, which is 120. For 60% you get 72, plus 60, so about 132. It tends to give slightly higher, more realistic easy-zone numbers for fitter people.
Important: some medicines, especially beta blockers used for blood pressure and heart conditions, keep your heart rate lower. If you take any heart or blood pressure medication, the formulas will not work for you. Speak to your GP before you start training by numbers, and use the talk test below instead. The NHS page on high blood pressure is a good starting point, and Blood Pressure UK has clear guidance on exercise and blood pressure. I have also written about exercise and blood pressure for parents.
The talk test: zones without a watch
This is what I use most in class, because nobody has to look at their wrist. The NHS describes moderate activity as raising your heart rate so you can still talk but not sing, and vigorous activity as hard enough that you cannot say more than a few words without pausing for breath (see the NHS physical activity guidelines).
- Easy (zones 1 to 2): you could hold a full conversation, even sing a line or two.
- Moderate (zone 3): you can talk, but singing is out.
- Hard (zones 4 to 5): a few words, then you need a breath.
The talk test is free, works with any medication and adjusts to how you feel on the day. After a night of a toddler climbing into your bed, your heart rate will run higher at the same pace. The talk test picks that up. A formula does not.
How to use zones in a busy week
The NHS recommends adults get at least 150 minutes of moderate activity or 75 minutes of vigorous activity a week, plus strength work on two days. Here is a simple way to spread that across a parent’s week using zones:
- Most of your cardio easy (zone 2): brisk walks on the school run, a gentle cycle, a steady jog where you could chat. Aim for 2 or 3 sessions of 20 to 40 minutes. If you want to go deeper, see my guide to zone 2 training.
- One harder session (zones 4 to 5): short intervals, for example 6 rounds of 30 seconds hard, 90 seconds easy. My HIIT for beginners post has a gentle starting plan.
- Two strength sessions: heart rate jumps around during lifting, and that is fine. Do not judge a strength session by its zone.
The common mistake I see is people doing everything in zone 3. Every run is “quite hard”, so they are always a bit tired but never push hard enough to improve their top end. Make the easy days properly easy and the hard days genuinely hard.
Heart rate zones in a bootcamp class
In a 45-minute bootcamp, your heart rate will move through most zones. The warm-up sits in zones 1 to 2, strength blocks hover around zone 3, and short finishers might touch zone 4 or 5 for a minute. That mix is the point. You get a bit of everything in one session.
My SYP Recharge energy and focus class is built around this kind of wave: moderate work, short hard bursts, then recovery. Every exercise has an easier and harder option, so if your heart rate is climbing too high, you drop to the easier version and stay in it. Nobody needs to know your numbers.
FAQs
What is a good heart rate zone to burn fat?
Watches often label zone 2 the “fat burning zone” because your body uses a higher proportion of fat for fuel at easy efforts. But what matters for body composition over time is your overall activity, strength training, food and sleep, not the zone of one session. Pick the effort you can keep doing week after week.
Is it dangerous to be in zone 5?
For a healthy adult, short bursts near maximum are normal during hard intervals. If you have a heart condition, high blood pressure, or any chest pain, dizziness or unusual breathlessness, stop and get checked by your GP before doing hard work. Build up to intense efforts gradually if you are new to exercise.
Are wrist heart rate monitors accurate?
They are decent at steady efforts like walking and jogging, and less reliable during fast changes, boxing or lifting where your wrist is moving and flexing. A chest strap is more accurate. For most parents, the wrist plus the talk test is good enough.
Book your first class
If you want to feel what easy, moderate and hard should be like without staring at a watch, come and train with me. SYP Bootcamp runs 45-minute small-group classes indoors in a church hall in Archway N19, with a maximum of 10 people and £15 a class. I will coach your effort level in real time. Book your £15 class here or call or WhatsApp me on 07301 512215. If you would rather have a plan built around your own numbers, you can see how 1-1 personal training works at SYP Fitness.
About the author
Artem Olekhnovych is a personal trainer in Archway and the founder of SYP Fitness and SYP Bootcamp. He has coached clients in Archway, Highgate and across North London for over 10 years, and runs small-group bootcamp classes for busy mums and dads. Read reviews from his 1-1 clients.
