A higher heart rate doesn’t always mean a better workout. Depending on your goal, the smartest move might be to push harder – or to deliberately hold back.
Heart rate zones split exercise intensity into ranges based on how hard your cardiovascular system is working, and training across them can transform how you approach every session. Our Challenge tracks are built around specific goals, and they take the guesswork out of this – guiding you on exactly which heart rate zone to train in for the results you’re after.
Join us as we break down how to calculate your heart rate zones, what each one means, and how to put that knowledge to work at your local F45 studio.
What are heart rate zones?
Your heart rate is how many times your heart beats per minute (bpm). Heart rate zones, then, are simply bands of that number, each linked to a different training intensity1. There are five zones in total, ranging from light movement to maximal effort.
Instead of thinking about a workout in simply “easy” or “hard” terms, heart rate zones give you a more precise read on how hard your body and heart are working.
In an F45 workout, we use the LionHeart heart rate monitor for heart rate zone training. It’s a wearable band that streams your live effort onto our studio screens during a workout and syncs to your phone. It calculates your heart rate against a target zone set for each workout, so you can see in real time whether you’re in the right zone to hit your goals.
How to calculate heart rate zones
To work out your heart rate zones, you first need an estimate of your maximum heart rate. A commonly used formula is:
Maximum heart rate = 220 − your age2.
This gives you a rough estimate of the fastest your heart can beat during all-out effort – and it’s the baseline everything else is worked out from, since each zone is simply a percentage of it. For example, a 30-year-old’s estimated maximum heart rate is around 190 bpm².
From there, each zone is calculated as a percentage of that number:
- Zone 1: 50 to 60% of maximum heart rate
- Zone 2: 60 to 70%
- Zone 3: 70 to 80%
- Zone 4: 80 to 90%
- Zone 5: 90 to 100%
This is a rough, rather than exact, figure – as actual maximum heart rate varies from person to person – but it’s a solid starting point for understanding which zone you’re training in.
Numbers only tell part of the story, though, and it’s just as important to listen to what your body is trying to tell you. If you’re exhausted, sore, or running on empty, your heart rate won’t pick that up, but your rate of perceived exertion (RPE) will. RPE is simply how hard a workout feels to you, usually rated on a scale of 1 to 10, and it’s a useful gut-check against the numbers on your wrist.
Heart rate zones 1 to 5 explained
At F45, we use heart rate zones for exercise to give you a clear read on exactly how hard you’re working in any given session. Read on as we break down each of the five heart rate training zones – unpacking what they feel like, and what they’re doing for your fitness.
Zone 1 heart rate: very light intensity
Approximately 50 to 60% of maximum heart rate1.
This is the easiest of the five heart rate zones, and it should feel that way. Your breathing stays relaxed, holding a conversation is no effort at all, and the whole thing feels like something you could keep doing for a long time without strain.
Because it’s so low-effort, zone 1 is ideal for warm-ups, cool-downs, active recovery, and dynamic and static stretches.
Zone 2 heart rate: aerobic endurance
Approximately 60 to 70% of maximum heart rate1.
Zone 2 heart rate sits a step up from zone 1: moderate, but still sustainable. Breathing is elevated but controlled, conversation is still possible, and you can hold this intensity for a while without it feeling hard. A simple way to check you’re in zone 2 is that you should be able to talk in full sentences, but singing would be a stretch.
You’ll typically land in zone 2 heart rate during things like cycling or slow jogging. It’s why most marathon runners spend the bulk of their training here – the effort is sustainable enough to rack up serious distance without needing to stop, building the aerobic base crucial for improving your running endurance.
Zone 3 heart rate: moderate-to-hard conditioning
Approximately 70 to 80% of maximum heart rate1.
Push a little further and you’re into zone 3 – breathing gets noticeably harder, and holding a conversation becomes a struggle. The effort feels challenging but still controlled, sitting somewhere between “comfortable” and “all-out.”
Think tempo runs, strength training, or pushing up a flight of stairs or a hill. Zone 3 heart rate builds your ability to hold harder efforts for longer, bridging the gap between aerobic training and higher-intensity work.
Zone 4 heart rate: hard, high-intensity work
Approximately 80 to 90% of maximum heart rate1.
Zone 4 heart rate should feel challenging. It’ll become harder to catch your breath and make conversation, and the intensity will be tough to sustain for long. This is because you’re training toward the upper end of the cardiovascular scale.
It’s the zone behind hard interval training and metabolic conditioning – workouts that challenge your cardio and muscles at once. Time here builds your tolerance for sustained harder efforts – teaching your body to hold on longer before stopping.
Zone 5 heart rate: maximal or near-maximal effort
Approximately 90 to 100% of maximum heart rate1.
This is as hard as it gets. Conversation is essentially impossible, and the effort is so intense that you’ll only be able to hold it for short bursts of exercise – typically 30 seconds to three minutes at most. Zone 5 heart rate is reserved for maximal or near-maximal intervals: sprint efforts, hard rows, bike or ski-erg pushes, and other high-intensity conditioning work.
How to use heart rate zones for your F45 Challenge goal
The Challenge tracks are a guided 45-day program where you choose a goal-specific track – Power, Lean, or Athlete – and get structured programming, nutrition guidance, and coaching built around it. You still get all the benefits of group fitness classes, but with added direction on things like session pacing, recovery, and the heart rate zone you should be aiming for.
Read on to find out how each track uses heart rate zones differently.
Power: manage intensity so you can produce more force
The goal of the Power track is to build strength, with a weight-focused program designed to boost your muscle endurance – helping you set goals and track measurable progress as you begin to lift heavier.
Mariam Allen is our athlete lead for the Power track, and as she explains: “With strength training, your form is everything. If your heart rate creeps too high, it usually means you’re rushing – and rushing under load is when technique begins to break down and injuries start to creep in. I want most of my athletes sitting around zone 2 to 3 for the bulk of their session – and only pushing into zone 4 for the more dynamic, explosive efforts.”
Lean: maintain an elevated but sustainable effort
The Lean track focuses on maximizing your calorie burn to improve your body composition, with programming designed to reduce body fat while preserving lean muscle. This program is designed to be a sustainable workout that’s hard enough to make a real difference, without being so intense that you can’t hold your effort for the entire class.
Lean track athlete lead Nic Wilson puts it in perspective: “I’ve seen people try to fix their results by adding more and more cardio – chasing internet numbers like 10,000 steps a day or 45 minutes on the StairMaster on top of everything else. Good news – we’ve designed this program so you don’t have to do that! Get your heart rate into zone 4, push into zone 5 on the sprints, and you’re already getting a serious calorie burn in 45 minutes.”
Athlete: combine aerobic fitness with higher-intensity work
The Athlete track is designed to improve your athletic performance, helping you build power, speed, and agility with detailed data to track your progress along the way.
Athlete track lead Jordi Duff explains why this range is key: “If you look at HYROX, athletes are sitting in zone 3 to 4 for the best part of an hour. We want to get you used to training in that zone regularly, so your body gets better at sustaining effort without your pace dropping.”
Heart rate zone training can completely change the way you train – helping you push harder when it counts and recover smarter when it doesn’t. Explore our Challenge tracks and find the program built around your specific goals.
1 https://pubmed.ncbi.nlm.nih.gov/35750282/
2 https://my.clevelandclinic.org/health/articles/24649-heart-rate-reserve
