The Apple Watch is capable of tracking many health-related aspects of your body, including heart rate. While it’s not as precise as the measurement a person would get in a hospital or medical setting, numerous studies over the past few years suggest the Apple Watch’s readings have a decent accuracy rate. The Apple Watch was first released in 2014, and it remains one of the most sought after smartwatches available.
Several smartwatches and fitness trackers on the market have the ability to track heart rate, but the Apple Watch remains one of the most commonly purchased products with heart rate tracking — and the most advanced on that front. It was even cleared by the FDA for its precision. However, there are factors that can affect the accuracy of its readings, and steps wearers can take to ensure they’re getting more reliable results.
Apple Watch's Different Heart-Monitoring Tools
The Apple Watch tracks heart rate using photoplethysmography. While this sounds complicated, it just means it uses light to track your heart rate. Red things, like blood, reflect red light and absorb green light. The Apple Watch uses green light to help detect how much light is being absorbed by the blood in the veins, and that fluctuation can be used to track heart rate.
The green LED lights flash hundreds of times each second in order to get an accurate reading. This is the type of reading it takes as someone is actively working out, and it s tracking heart rates that are 30–210 beats per minute. The heart rate sensor also uses infrared light to track heart rate in the background all the time, and to provide heart rate notifications.
More recent models of the Apple Watch (Series 4, Series 5, Series 6, Series 7, Series 8, Ultra 2) take heart monitoring a step further using electrodes to perform an electrocardiogram (ECG/EKG), or a reading of the heart’s electrical signals. These electrodes are built into the Digital Crown and the ring on the back of the Apple Watch surrounding the LEDs. “When you place your finger on the Digital Crown, it creates a closed circuit between your heart and both arms, capturing the electrical impulses across your chest,” Apple explains on its page. This feature can be used with Apple’s Heart rate app or the dedicated ECG app.
How To Increase The Accuracy Of Readings
The latter method of tracking heart rate using the Digital Crown on the side of the Apple Watch is much more accurate because of this closed circuit it creates. s will also get a much faster reading than what they'd experience with other methods. Still, the Apple Watch’s accuracy level can be different from person to person. There are things that can be done to help get a more accurate heart rate reading more consistently.
Making sure the Apple Watch fits well is one of the best ways to ensure an accurate reading. The watch should be not too tight or too loose, and it needs to remain on the top of the wrist at all times. Wrist detection also needs to be turned on in order to have heart rate detection whatsoever. Anytime the Low Power Mode is turned on, the heart rate sensor will also stop tracking background heart rate and providing heart rate notifications. Tattoos, skin perfusion, and the type of movement may also affect the accuracy of the Apple Watch readings. You can also pair an external heart rate monitor to the Apple Watch via Bluetooth to get more accurate readings.
How Often Does Apple Watch Track Heart Rate?
The Apple Watch measures heart rate continuously during a workout, and for three minutes after it ends to determine recovery. The purpose of this is to not only monitor heart rate levels, but also to calculate calories burned during a workout. While some workouts like running or cycling provide better results due to their rhythmic nature, others like tennis or boxing might not be as accurate. Either way, Apple recommends always choosing the right workout on the Watch to get the best results.
Apart from this, the Apple Watch tracks your heart rate through the day – basically the entire time it's strapped to your wrist. It's advisable to set up heart rate notifications because of this. If your heart rate goes higher or lower than a chosen BPM, Apple Watch will send you a notification. Additionally, the watch will continue to check for irregular heart rate notifications through the day to check for signs of atrial fibrillation (Afib). While the Apple Watch's heart rate readings can't be compared to a medical device, it is a useful baseline monitor for keeping continuous tabs on heart rate, and has provided life-saving alerts to s on multiple occasions.
Source: Apple