The best way to monitor your heart rate with a smartwatch

Wearables are getting serious about health, and the use of health and wellness features, such as heart-rate monitoring and pulse-oximeter tracking, has become increasingly popular.

But why measure your heart rate, and can you rely on your wearable to track it accurately? 

We reveal the fitness trackers and smartwatches that offer more sophisticated heart-health features and explain more about how they work.

Browse the best smartwatches to see which come out on top, or check our guide to the best smart rings.

Why monitor your heart rate?

If you have any concerns about your heart, you should, of course, see your doctor. Assuming your interest is more casual, a heart-rate-monitoring wearable can be a big help in helping you get the most from your workouts.

By monitoring your heart rate, you can make sure you're pushing yourself hard enough during bouts of high-intensity exercise and recovering enough afterwards.

Longer term, keeping an eye on your heart-rate patterns can help you notice what may be causing spikes during everyday life and tell you a lot about your cardiovascular health.

Wearables that collect data on your heart rate can also give you more accurate feedback on other aspects of your health - for example, your sleep, calorie burn, stress levels and VO2 max (an estimate of the maximum amount of oxygen that you use during exercise - and therefore, a measure of your aerobic fitness).

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Best fitness tracker with heart-rate monitor

If you don't want a smartwatch, there are plenty of lightweight fitness trackers that offer great heart-rate monitoring.

Best smartwatches with heart-rate monitor

If you’re looking for something a little more advanced, it’s worth considering a smartwatch. These usually offer all of the same features as fitness trackers as well as having the ability to link together notifications from your smartphone - and often on a much bigger screen.

We see big differences in how accurately wearables can measure your heart rate, though. Some manage this very poorly, while others only manage to report accurately in certain conditions (such as struggling during low-intensity exercise, but getting more accurate at higher intensities). These include wearables at the cheaper end of the market, as well as more expensive models.

Apple Watch and other smartwatches with advanced heart-rate features

Released in 2018, the Apple Watch Series 4 was the first smartwatch to offer ECG (electrocardiogram) readings directly from your wrist via an electrical heart-rate sensor.

The sensor measures the electrical signals in your heart to check for atrial fibrillation, or AFib (irregular heart-rate rhythms), which can put you more at risk of stroke. You can download readings into a PDF to share with your doctor.

It also has an optical heart-rate sensor (light from the sensor penetrates the skin to estimate heart rate). This measures your heart rate throughout the day and calculates various metrics for you, including the average heart rate while you're walking, your Heart Rate Variability (HRV) and heart rate during a workout, and Breathe (guided breathing) sessions.

You can also check your heart rate at any given moment by opening the Heart Rate app, and you can turn on the option to get notifications if your heart rate goes above or below a chosen beats per minute (BPM).

The more recent Apple Watch Series 9 and Series 10 also offer all of these features - some earlier models have some, but not all (not the ECG feature, for example). However, the Apple Watch is expensive compared with other smartwatches. 

Compare all Apple Watch models in our Best Apple Watch to buy guide.

Other smartwatches for tracking heart health

If you’re an Android user, a Samsung Galaxy Watch or Google Pixel smartwatch might catch your eye. Alongside the usual heart-rate monitoring, they have the ability to monitor your blood pressure or perform an ECG test on your heart rhythms. They can estimate your VO2 max (a measure of your aerobic fitness) too.

See how well Android-compatible smartwatches fare in our rigorous performance tests.

Specialist heart health wristwatch: Omron HeartGuide

Some wearables go beyond this, making heart health their USP. The Omron HeartGuide (£499) is one such device and was marketed as the world's first clinically validated wearable blood pressure monitor.

It promises to monitor your blood pressure, steps, distance, calories and sleep, and it displays some (limited) notifications from your smartphone. Omron says the HeartGuide can also measure your heart rate, but it will do so only when you ask it to measure your blood pressure.

You'll need nimble fingers to take it on and off, though, which you'll need to do each time you want to do the washing up or go for a swim. It can survive being splashed with water while you wash your hands, if you're careful, but it can't survive being submerged in water. The watch also feels heavy and cumbersome.

Note that Omron says you shouldn't use the Heart Guide if you've had a mastectomy. Traditional blood pressure monitors can carry similar warnings.

Head to our guide on the best blood pressure monitors for more handy hints and tips to get the most for your money.

How to make sure you're tracking your heart rate accurately

There are a few things you can do to give your wearable the best chance of tracking your heart rate accurately.

• Make sure your smartwatch or tracker is sitting snugly but comfortably on your arm, with the sensors flat against your skin above the wrist bone
• Keep the smartwatch or tracker clean (following the manufacturer instructions, to avoid damaging it). Sweat can also interfere with readings
• If you have poor circulation or you just feel cold, warm up a little before taking a reading
• Smoking or drinking alcohol before taking a measurement can cause your heart rate to differ from your normal readings. Try taking a measurement again later.

Read more about the best Android smartwatches

Tattoos and heart-rate sensors

A number of manufacturers say that having tattooed wrists can interfere with heart-rate monitoring. For example, Apple states that “the ink, pattern, and saturation of some tattoos can block light from the sensor, making it difficult to get reliable readings”. Garmin has a similar statement on its website. 

If you have one heavily tattooed wrist, wear your wearable on the other one if it's clear for everyday use. Most smartwatches and fitness trackers have settings so you can select what wrist you’re wearing it on, so it shouldn’t matter if it’s your dominant or non-dominant hand. 

See all our smartwatch reviews and fitness tracker reviews.