One of the first things new members ask us when they walk into the studio is what the numbers on the screen mean. Everyone gets a heart rate monitor, everyone’s name comes up on the wall, and within a few sessions most people are glancing up between rounds to see where they are. A few weeks in, the same people tell us it’s the thing that changed how they train.
That isn’t because the tech is clever. It’s because heart rate tells you something your brain is genuinely bad at judging on its own: how hard you are actually working. Here’s what the zones mean, why we train with them in every session at our Loughton studio, and why the goal is not to sit in the red for 45 minutes.
What Heart Rate Actually Tells You
Your heart rate is a live readout of how much work your body is doing. The harder your muscles are working, the more oxygen they need, and the faster your heart has to pump to deliver it. That makes it one of the most honest effort measures there is. It doesn’t care how you feel about the session or how much you slept. It just reports what is happening.
The problem with training on feel alone is that perceived effort is wildly unreliable. On a good day you think you’re working harder than you are. On a tired day a moderate effort feels brutal. Some people consistently underestimate what they’re capable of, and others go flat out on every exercise and wonder why they’re wiped out by Wednesday. A heart rate number takes the guesswork out of it.
The Five Heart Rate Zones in Plain English
Heart rate zones are usually worked out as a percentage of your maximum heart rate. A common starting estimate is 220 minus your age, so a 40 year old would have an estimated maximum of around 180 beats per minute. It is only an estimate and real maximums vary a lot from person to person, which is why your numbers get more accurate the more you train with a monitor.
Zone 1 (roughly 50 to 60 percent of max). Very light. Walking, warming up, recovering between efforts. You could hold a full conversation without thinking about it.
Zone 2 (60 to 70 percent). Comfortable and steady. You’re breathing a bit harder but could keep going for a long time. This is where a lot of your aerobic base and fat burning capacity is built.
Zone 3 (70 to 80 percent). Moderate to hard. Talking is possible but you’d rather not. This is where your general fitness improves and your heart gets better at pumping more blood per beat.
Zone 4 (80 to 90 percent). Hard. Short sentences only. This is the zone that drives the biggest improvements in fitness and is where good HIIT work spends a lot of its time.
Zone 5 (90 to 100 percent). All out. You can only hold it for short bursts before you have to back off. Brilliant in small doses, counterproductive if you try to live there.
Why Redlining Every Session Is Not the Goal
There’s a myth in fitness that if you’re not on the floor at the end of a session, it didn’t count. It’s one of the biggest reasons people burn out, pick up niggles and quit.
High intensity training works because of the contrast between hard efforts and recovery. You push into zone 4 or 5, then you let your heart rate come back down, then you go again. Those recovery periods aren’t wasted time. They’re what allow you to hit the next effort properly. If you never recover, every interval becomes a slightly worse version of the last one and you end up stuck in a grey middle ground where you feel exhausted but aren’t actually working at a high enough quality.
The other benefit of watching your heart rate come down between rounds is that it shows you your fitness improving in real time. One of the clearest signs of a fitter heart is how quickly it recovers after a hard effort. Members who start out taking a couple of minutes to settle often find that within a few months they’re recovering in half the time. That’s progress you can see on the screen, not just feel.
Training to Your Effort, Not Someone Else’s
This is the part we care about most, and it’s the reason we use heart rate monitoring in every single session rather than as an optional extra.
In a small group, you might have someone coming back after years away from exercise training next to someone who runs half marathons. Without heart rate data, the natural thing is for everyone to compare themselves to whoever is fastest. The beginner overdoes it trying to keep up. The fitter member coasts because they look like they’re doing well compared to the room.
Heart rate fixes that. If both of them are in zone 4, they are both working at the right level for their body, even if one is doing twice as many reps. Nobody is left behind and nobody gets to hide. It also means our coaches can see at a glance who needs pushing, who needs to ease off, and who is having an off day and needs a different version of the exercise.
It’s the closest thing to having a personal trainer watching your effort the whole time, in a group setting where you still get the energy and accountability of training with other people.
Health First, Then Intensity
Heart rate training is safe and effective for the vast majority of people, but if you have a heart condition, high blood pressure, take medication that affects your heart rate (beta blockers are the common one), or you’re returning to exercise after a long break with health concerns, speak to your GP before jumping into high intensity work. Some medications lower your heart rate, which means the standard zones won’t apply to you and need adjusting.
This is one of the reasons we offer GP led health assessments at the studio. Having a clear picture of your blood pressure, resting heart rate and general health before you start means your training can be set up around you from day one, rather than guessed at.
How to Use Heart Rate If You Train on Your Own
If you’ve got a smartwatch or chest strap, a few simple rules will help you get more out of it:
Use a chest strap for intervals if you can. Wrist based monitors are fine for steady exercise but tend to lag behind during fast changes in effort.
Don’t chase one number. Look at the shape of the whole session. Hard efforts should climb into zone 4 or above, and recoveries should come back down.
Mix your week. Not every session needs to be maximal. Two or three high intensity sessions a week, balanced with walking and lower intensity movement, is plenty for most people.
Track your resting heart rate. A resting heart rate that is creeping up over a few days can be a sign you’re under recovered, stressed or coming down with something. It’s a good cue to take it easier.
Want to See Your Own Numbers?
If you’d like to train with live heart rate monitoring and coaches who actually use the data to look after you, that’s exactly what we do at our Loughton studio. Small group HIIT sessions, every effort tracked, and a community that keeps you turning up.
We start everyone with a free goal setting consultation, where we talk through where you are now, what you want to achieve and how we would set your training up. No pressure and no obligation. Get in touch with the team and we’ll get it booked in.
Restarting your training this autumn? Read The September Reset: Why September Beats January for Getting Back in Shape. Or if you’re weighing up your options, have a look at HIIT vs Traditional Gym Training: What Actually Gets Results?
