Knowing how to use a heart rate monitor can unlock a whole host of benefits for your training, performance and recovery.

Measuring your heart rate during workouts serves up some big benefits – whether you wear a heart rate monitor while running outdoors, or you connect your gadget to one of the best rowing machines or your favorite exercise bike or treadmill at home. Heart rate training helps you manage the intensity of your workouts better, provides personalised data for optimal training and gives you insights to avoid overexertion and injury. It can even provide added motivation and accountability when chasing your fitness goals.  

With most fitness trackers and GPS sports watches offering built-in optical heart rate sensors for tracking your heart’s beats per minute (BPM) during and outside of your workouts, you might wonder why you need another heart rate monitor.   

Heart rate monitor accuracy

The main reason to invest in one of the best heart rate monitors is increased accuracy over the optical sensors on fitness watches. Using medical-grade electrocardiogram technology, chest straps provide a more precise way to track heart rate and monitor intensity and progress. Optical sensors like the Polar Verity Sense just don’t provide the same fidelity. If your workout involves a lot of arm movement, fast and big shifts in intensity, or exposure to cold weather, they can often struggle.

Not only are chest strap heart rate monitors like the Garmin HRM-Pro Plus, Polar H10 or Wahoo TICKR X closer to the source, their method of measuring – via electrodes on the skin logging your heart’s electrical activity –  is more precise and immediate. Optical monitors rely on reflected light to measure your blood flow, and hence your heart rate, and it’s just not as quick.

The more accurate information you feed into the training insights tools we now see on the best fitness watches, the better. Those readouts like the training effect of your sessions, recovery time recommendations and fitness estimations all work off heart rate and they’re only as good as the data you feed them. You can often override the inbuilt optical sensors on sports watches like the Garmin Forerunner 955 by wirelessly connecting to a chest strap to increase that accuracy.

Heart rate monitor connectivity

Heart rate monitors wirelessly connect and sync with other gear in one of two ways – by Bluetooth and ANT+. Either one will let you connect with a device supporting the same protocol. The only real difference is ANT+ is a slightly slower, lower power way of transferring data over a shorter distance – the upside being devices can often support multiple, if not unlimited simultaneous ANT+ connections. Using Bluetooth you can often only connect to two or three other devices at best.

Using heart rate monitors to track your workouts

Heart rate monitors will let you assess your workout in various ways. Some arm-mounted optical sensors, like the Myzone MZ-Switch, give visual feedback as to what heart rate zone you are in via coloured LEDs – but that’s only useful if you’re not wearing layers over it. Pairing with your smartwatch will give easily accessible BPM and zone feedback on the fly.

If you’d rather not invest in a pricey sports watch, you can use the tech you already have and pair it with your phone – which is useful for post-workout analysis. Of course if you have access to ANT+ or Bluetooth enabled kit like rowers, e-bikes, exercise bikes like the AssaultBike Classic and other gym kit you can review heart rate data in real time there too.

A man holding a heart rate monitor and looking at workouts on a phone
Heart rate monitors like Polar display real-time date on accompanying apps

Heart rate training zones

The best way to get the most out of a heart rate monitor is to understand the five heart rate training zones and the benefits of each. Are you exercising to lose weight, improve fitness or maximise performance? Each goal will require spending most of your workout time in an certain zone. If you’re doing intervals you’ll be looking to track your heart rate between zones.

The first thing to do is to work out your maximum heart rate – from here you can calculate your training zones. The easiest way to get a rough figure is to subtract your age from 220 beats per minute (a 30-year-old’s maximum heart rate would be about 190bpm).

So using a 30-year-old as an example, these are the target heart rates for your training zones:

Zone 5Anaerobic zone90-100% effort176-190bpm
Zone 4Threshold zone80-90% effort162-176bpm
Zone 3Aerobic zone70-80% effort148-162bpm
Zone 2Endurance zone60-70% effort134-148bpm
Zone 1Recovery zone50-60% effort120-134bpm

Of course, those BPM ranges will differ depending on your age. If you’re 40, your max heart rate will be 180bpm, so your zone 1 will start from 90bpm (50%), your zone 2 from 108bpm (60%) and so on. It’s easy to figure out but most fitness trackers or sports watches will ask you for your age or maximum heart rate and work out your zones for you.

Heart rate zones for fat loss and recovery

If you’re looking to trim fat, you want to spend most of your workouts in zones 1 and 2. Zone 1 encourages the flow of blood and is where you want to be for warm-up and cool-down sessions. This is also where to concentrate for longer recovery workouts the day after hard sessions. Zone 2 enhances the efficiency with which you use fat and carbs as fuel. It’s also preparing your body for higher intensity training.

Heart rate zones for aerobic endurance

Zone 2 is the gateway to improving endurance and aerobic fitness. Moving into zone 3 enhances your lung capacity and lactate tolerance, and improves how efficient your body gets oxygen to your muscles. Zone 3 also helps strengthen your heart and helps you exercise longer before becoming fatigued.

Heart rate zones to maximise performance

If you’re looking to increase speed and performance then you need efforts in zone 4 and short bursts in zone 5. Zone 4 will help developing your high-speed endurance and will burn carbs, not body fat. Zone 5 develops maximum performance and speed – short bursts in this zone will help you go at your maximum effort for longer. Unless you’re already fit or a competitive athlete, you shouldn’t be looking to go into zone 5.

Trying to push all your sessions into zones 4 and 5 will put significant strain on your body and you won’t be able to sustain it for very long. You’re more likely to injure yourself, over-train and burn out. Conversely, spending all your workouts in the recovery zone won’t challenge your body enough to improve its efficiency.

How to use a heart rate monitor for aerobic endurance training

Essentially if you want to improve your cardiovascular fitness, you want to concentrate your efforts in the aerobic endurance zone – so that’s zones 2 and 3. This will get your heart and lungs working hard enough to improve oxygen intake and distribution.

So think of zones 2 and 3 as the sweet spot – the magic numbers. Concentrate your efforts here and you’ll see and feel your endurance and aerobic fitness improve, and your body fat will act as fuel. You’ll need to spend more time in zone 2 to burn the same calories as shorter efforts in higher zones, but more than 60% of those you do burn will be fat. Dip into zones 4 and 5 for high performance gains, but it’s carbs that fuel these efforts.