How does Apple health calculate resting heart rate?


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Page last updated: 28/09/2022

How does Apple health calculate resting heart rate?

In this guide, we will discuss How does Apple health calculate resting heart rate, how Apple Watch measures your heart rate and some tips in getting a better or more accurate reading. Additionally, we make a few recommendations on the data you might get and how it could be influenced by many factors. 

How does Apple health calculate resting heart rate?

If you wonder how Apple health calculates resting heart rate, here we have the answer. The Apple Watch has LED lights that keep flashing hundreds of times per second calculating the number of times your heart beats each minute (bpm). Moreover, the optical sensor supports a range of 30 to 120 beats per minute.

For many users, checking their heart rate is a must and for others, it is simply a way to keep track during workout sessions, overall health. If you want to check your heart rate, simply open the Heart Rate app and wait for your Apple Watch to measure your heart rate. However, you can also monitor your resting, walking, breathe, workout and recovery states throughout the day. 

Finally, you can easily open the app, add the Heart Rate monitor to your watch face or add the Heart Rate app to the Dock. Also, you can turn on the heart rate notifications, so you get an alert when your heart rate remains above or below a chosen beats per minute, or to check if you have an irregular heart rhythm. 

When does my Apple Watch measure my heart rate?

When using the Workout app, your Apple Watch measured your HR continuously during the workout session and for 3 minutes after you have finished so it can determine your recovery rate. If you are not able to see your HR check the settings.

Additionally, the recorded information helps Apple Watch estimate how many calories you have burned. Also, the Apple Watch will measure your HR throughout the day when you are still and periodically when you are walking. However, since the Apple Watch takes these background readings based on your activity, the time between these measurements may vary. 

Therefore, the Apple Watch will also calculate your daily resting rate and your walking average by correlating background HR readings with accelerometer data when sufficient background readings are available. 

How does Apple health calculate resting heart rate?

How does Apple Watch measure my heart rate?

Just as we have discussed, the optical sensor uses what is known as photoplethysmography. As indicated on, “This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment”.

When your heart beats, the blood flow that goes through your wrist is greater but between beats, it’s less. The optical heart sensor is designed to compensate for low signal levels by increasing both LED brightness and sampling rate. 

Moreover, Apple indicates, “The optical heart sensor can also use infrared light. This mode is what Apple Watch uses when it measures your heart rate in the background, and for heart rate notifications. Apple Watch uses green LED lights to measure your heart rate during workouts and Breathe sessions, and to calculate walking average and Heart Rate Variability (HRV)”.

For better results 

Make sure your watch is not too tight or loose, however, consider that even under the best or ideal conscious, your Apple Watch may not be able to get a reliable heart rate reading every time for everyone. 

Moreover, for a small percentage of users, there may be various factors that may make it impossible to get any heartbeat reading at all. But there are a few things you can do to help your Apple Watch get the most consistent and accurate reading possible. To learn more on what else could affect the readings, click here.

Resting Heart Rate

The resting heart rate reading will tell you how many times is your heart beating per minute while at rest. Consider that your heart rate tends to beat slower when you are sleeping so if you are wearing the watch at night, while you sleep, you may get a lower reading than the ones you would normally get during the day. No need to be alarmed but if you are, always consult with a physician. 

As indicated by, “the more athletic you are, the stronger your heart will be. A strong heart doesn’t need to beat very many times per minute to keep your body full of fresh blood. Really fit people tend to see lower numbers here than people who don’t work out. And as you get more fit, you may see your resting heart rate drop over time”.

However, if your heart rate at rest increases, something may be wrong as a result of overtraining or you could be sick. The number reflected should be a bit lower than what you would see while you are up and about, so maybe between 60 to 80 bpm for most of us but it could be lower than that if you are really fit. 

Walking Average

This is the heart rate the watch detects when you’re walking around. This number should be more than your resting heart rate but not especially high. For most of us, if you are at home walking from the bed to the fridge, it is between 70 to 80 bpm but if you do a lot of brisk walking, it could increase to 110-120 bpm. 

What if I am concerned about some of the readings?

Remember that your Apple Watch is not meant to help diagnose any medical conditions. However, we know how frequent it is to get alarmed by a reading we considered to be too high or too low and the best thing we do at that moment is google our heart rate. However, we strongly recommend to avoid doing that and instead, seek medical advice.

Why is this blog about How does Apple health calculate resting heart rate important?

Knowing how does apple health calculate heart rate might seem important to many users because they would like to keep monitoring their heart rate for health purposes. However, remember that the readings may not be accurate and there are several factors that could have influenced it. If you have concerns, always consult with a physician or health professional about it. 

Moreover, avoid googling a certain reading because it might alarm you more than it really should. Remember that the reading may vary from one person to another and it doesn’t mean there is something wrong with them. 

Please feel free to leave any comments or thoughts about the content of this article!

Frequently Asked Questions (FAQs) about How does Apple health calculate resting heart rate

Is Apple resting heart rate accurate?

The Apple Watch Heart Rate monitor may be accurate for detecting atrial fibrillation in older people. However, researchers have found that the accuracy rate is only about 34% overall, and further studies may be needed to confirm how accurate is the Apple Watch heart rate monitor.

How does a health app measure heart rate?

The Health app can measure your heart rate and all you need to do is place your fingertip on your phone’s camera lens and the app will detect the colour change on your fingertip each time your heart beats (iPhone 6). Then, it uses the information collected to calculate your heart rate but if you are using the Apple Watch it may measure your heart rate automatically.

What is the most accurate way to find your resting heart rate?

It is believed that the most accurate way to measure your resting state is using a wireless monitor strapped around your chest. It reads out to a fitness tracker worn on your wrist but a smartwatch may also do the trick. Digital fitness trackers worn on the wrist such as at-home blood pressure machines or smartphone apps are believed to be less accurate than checking your heart rate manually.

Is 55 a good resting heart rate?

A normal range when resting is 50 to 100 beats per minute. If your resting heart rate is higher than 100, it is known as tachycardia and below 60 is known as bradycardia. Increasingly, experts pin an ideal resting heart rate between 50 and 70 bpm.

How accurate is Fitbit heart rate?

The Apple Watch 3 and Fitbit Charge 2 were generally highly accurate across the 24-hour condition. Specifically, the Apple Watch 3 had a mean difference of −1.80 beats per minute (bpm), a mean absolute error percent of 5.86%, and a mean agreement of 95% when compared with the ECG across 24 hours.