When Apple Watch Measures Your Heart Rate
When you use the Workout app, Apple Watch measures your heart rate continuously during the workout and for 3 minutes after the workout ends to determine a workout recovery rate. If you don’t see your heart rate, check your settings.
This information, as well as other data it collects, helps Apple Watch estimate how many calories youve burned. In addition, Apple Watch measures your heart rate throughout the day when youre still, and periodically when youre walking . Since Apple Watch takes these background readings based on your activity, the time between these measurements will vary. Apple Watch also calculates a daily resting rate and walking average by correlating background heart rate readings with accelerometer data when sufficient background readings are available.1 You can control which third-party apps have access to your health data from the Health app in Sources.
The Choice Between Chest Straps And Optical Monitors Is More Complex Than It Seems
by Valentina Palladino – Apr 2, 2017 1:00 pm UTC
If you want to get a fitness tracker, you have to decide is if you want one that’s compatible with a heart-rate monitor. Learning your heart-rate patterns, both during a workout and during daily activity, can show you a lot about your health. According to Harvard’s Health blog, your resting heart rate is a key factor to determining your overall current and future health, and monitoring heart-rate changes over time can give you more of the information you need to lead a healthy life.
Chest straps and optical heart-rate monitors are the two most common types of pulse trackers available for modern wearables, and they both use similar methods to measure your pulse. However, their key differences in methodology and design will dictate which device you choose when picking a workout companion.
How Heart Rate Sensors Work
The optical heart-rate sensor found in most fitness trackers and smartwatches today uses photoplethysmography , which projects a green light on the skin. The light that isn’t absorbed by the tissue beneath the skin is reflected back to the sensor, which then measures the variations to calculate your heart rate.
Chest-worn monitors, including the Polar H10 we tested the wrist-worn trackers against, use electrodes to measure your pulse, which is more accurate than PPG technology. The strap is worn closer to the heart and is less prone to sliding around while exercising, which leads to more accurate heart-rate readings.
There are pros and cons to both. I prefer a wrist-worn tracker to a chest strap because I find chest straps to be uncomfortable and awkward to wear. But fitness trackers and smartwatches have to fit just so to take accurate readings. I wore the wrong-size band to initially test the Samsung Gear Sport, and the results were wildly inaccurate.
MORE: Fitness Tracker Buying Guide
“We know from our studies that the accuracy of any one of those devices can vary substantially based on the fit,” said Dr. Gregory Marcus, director of clinical research for the University of California, San Franciscoâs Division of Cardiology. “Sometimes to get the most accurate measurements, it needs to be quite tight â to the point where it can be uncomfortable. It’s not necessarily the sophisticated technology inside the PPG sensor sometimes it’s about the fit.”
Also Check: How To Find Resting Heart Rate
Testing Optical Heart Rate Monitors
To evaluate the accuracy in a more quantifiable manner I’ve analyzed the heart rate of readings of several optical heart rate monitors compared with a chest strap based monitor. I’ve spent months gathering over 1 million data points, and developing analysis software defined patterns in the data. I found two factors that influence the accuracy temperature and rate of change of heart rate . I’m defining ÎHR as the difference between the highest and lowest heart rate values recorded using the chest strap in the preceding 60 seconds, so a ÎHR of 5 could come from a heart rate range of 130 to 135.
- About 78% of readings across all of the optical heart rate monitors is within 3 BPM of the correct reading. That’s pretty grim in my opinion.
- When the temperature is warm about 83% of readings across all of the optical heart rate monitors is within 3 BPM of the correct reading.
- When the ÎHR is 5 BPM or less, about 85% of readings across all of the optical heart rate monitors is within three BPM of the correct reading.
- When the temperature is warm and ÎHR is 5 BPM or less, about 90% of readings across all of the optical heart rate monitors is within three BPM of the correct reading.
What Is A Heart Rate Monitor
Heart rate monitors measure your heart rate while working out, which may help you reach your target rate safely and efficiently without exceeding your maximum heart rate.
You can use heart rate data to adjust your intensity, maintain an appropriate pace, and boost your cardiorespiratory endurance. Over time, you may be able to sustain higher intensities for longer durations with a lower heart rate.
Some heart rate monitors track only your heart rate, while others provide additional workout metrics such as speed, distance, and breathing rate.
Keep reading for our picks of the 9 best heart rate monitors, plus tips on how to choose the best monitor for you.
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What Are Heart Rate Monitors
Heart rate monitors are devices that detect and measure your heart or pulse rate. Thanks to advances in technology, these devices are small, wearable and many use sensors that are very accurate. However, while these devices are excellent for personal use, theyre no substitute for medical devices that are much more accurate.
Optical Heart Rate Measurement: Measure Heart Rate During Workouts
Optical heart rate sensors are especially useful during exercise. They tell you how your heart rate develops during a workout, but also give recovery advice. Some smartwatches offer the possibility to train in heart rate zones. This way, you know exactly when to slow down or take an extra step during a workout to maintain the right heart rate.
Also Check: Guideline Directed Medical Therapy Heart Failure
How To Choose The Best Heart Rate Monitor
There are many great heart rate monitors on the market. However, to find one thats right for you, its important to think about which metrics youre interested in and what type of monitor you need.
For example, some monitors only keep an eye on heart rate, while others offer additional fitness metrics, such as stride length, cadence, or blood pressure.
While some heart rate monitors are in the form of a chest band, armband, or watch, other options include hats and earbuds.
In general, chest straps tend to be the most accurate, as they use electrode sensors and are tightly pressed against your body.
In contrast, armbands and watches use optical sensors, which may be less precise but offer greater convenience and are more comfortable for all-day wear.
Youll also want to think about any additional features you might need. For example, some of the monitors on our list offer features designed for swimmers or cyclists, such as water resistance, GPS navigation, and internal memory for offline workouts.
If you want to pair your data with your smartphone, youll want to look for a monitor with Bluetooth or ANT+ capabilities.
When considering your budget, make sure to factor in any additional costs, such as subscription fees.
Heres a quick look at how our picks compare:
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What To Look For In A Heart Rate Monitoring Device
For a truly effective device, youll want to make sure your optical heart rate monitor has a high sampling rate. This indicates how many times per second the device can capture information from your pulse. The typical range is anywhere from 20 to 200 beats per second. A higher sampling rate usually means a more accurate reading.
Additionally, when looking at optical heart monitors, users need to understand that they are not medical devices or intended for diagnosis of any conditions like undiagnosed chest pain that could be a symptom of coronary artery disease but rather are designed to get you up and to move, track steps taken, and calories burned during your workout.
Remember, you can always use a chest strap if you need more accurate information. But if all you want is a computer that will help motivate you to stay fit and healthy, then an optical heart monitor will do the trick.
When it comes to picking a fitness tracker for a specific activity like running or cardio equipment at home like a treadmill, elliptical machine, or exercise bike, look for one with a heart rate monitor in-built into the device itself rather than purchase another accessory for measurement at the wrist.
Also Check: Normal Heart Rate When Standing And Walking
Optical Heart Rate Monitoring
Optical Heart Rate Monitoring detects the changes in blood flow that occur with each heartbeat. Most optical heart rate monitors for use while exercising shine a green light into the skin and use a receptor to detect the changes in the reflected light. This approach has been used for decades, and I had an early version back in the 1980s. The latest optical heart rate monitors are vastly superior, but still have many accuracy issues. The most accurate form of heart rate monitoring is to use a chest strap that picks up the electrical signal from the heart. While a chest strap is not perfect, it works remarkably well as long as it has good contact with your skin, the battery is not flat, and the strap is not damaged. The accuracy of Optical Heart Rate Monitoring will depend on a number of factors:
What Type Of Results Do You Get And What Do The Results Mean
Depending on the device youre using, the results might have slightly different meanings.
- Electrical-detection devices: These are the only devices that truly detect your heart rate. Thats because they are picking up the electrical activity of your heart itself.
- Optical-detection devices: These devices detect your pulse rate, not your heart rate.
Regardless of whether or not they measure your heart rate or your pulse rate, the results try to convey the same thing: How many times your heart beats per minute. Depending on the device, they may also measure and display other metrics, like heart rate variability. Some also use apps that offer you that data in ways that you can tailor to your uses and needs.
Read Also: Echelon Heart Rate Monitor
How Does Optical Heart Rate Monitoring Work
Most wearables with heart rate monitors today use a method called to measure heart rate. PPG is a technical term for shining light into the skin and measuring the amount of light that is scattered by blood flow. Thats an oversimplification, but PPG sensors are based on the fact that light entering the body will scatter in a predictable manner as the blood flow dynamics change, such as with changes in blood pulse rates or with changes in blood volume .
Why Train With A Heart Rate Monitor
Finding your personal heart rate zone and training with heart rate intervals allows you to maximize your workout. Simply put, if you train at lower heart rates it will require you to workout longer to achieve benefits. If you work out at BPMs that are too high for a prolonged period, you will burn out too fast, before you’ve reached your workout goals. Rhythm+ has advanced optical sensors that will give you a precise BPM reading so you can stay in your zones and receive the maximum benefit from your workout! Train Smart, Get Fit. This chart illustrates the relationship between heart rate levels and workout efficiency during interval training. Please consult your physician before starting any exercise routine to ensure that you are healthy enough to engage in a training regiment. Heart rate zones vary by a person’s age, consider consulting a personal trainer regarding the appropriate heart rate zones for you.
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What Is The Best Way To Track Heart Rate
The best way to track your heart rate is with a chest strap heart rate monitor, because this type of monitor provides the most accurate results .
You can also use a wearable device such as an armband, smartwatch, or wrist fitness tracker. Other options include earphones, exercise machines, and blood pressure machines.
While you can manually measure your heart rate by taking your pulse, a wearable device will provide more accurate results and allow you to track your heart rate over a set period or during an activity.
Some devices provide additional metrics that give you valuable insight into your heart health, fitness level, and overall health.
Your Wrist Heart Rate Monitor Data Seems Wrong It Probably Is
If you train with a wrist-based optical heart rate monitor, chances are its not always giving you the right readings.
Have you ever been in the middle of a workout and looked down at your watch to find an unexpected number in the heart rate data field? I know I have.
Theres no way Im beating at 180, Ill think. And it turns out, my thoughts were probably right. Data from your wrist heart rate monitor is not always reliable.
Tracking your heart rate data is interesting because it can tell you a lot about your fitness and general health.
Especially when you exercise, knowing your heart rate can tell you whether youre working close to your maximum or if you could push a little harder. Conversely, it can also tell you if youre working too hard during a training session that was meant to be easy.
While your heart rate is affected by variables such as sleep and stress, it is still a very reliable metric to measure exercise intensity at any given time. Only applicable, though, if the data is accurate.
Read Also: What Should Your Heart Rate Be When Running
What Metrics Can You Get From Ppg Sensors
Its really easy to make a bad PPG-based wearable. While PPG is really hard to get right, when you do get it right, it can be very powerful. A high-quality PPG signal is foundational to a wealth of biometrics that the marketplace is demanding today. For example, heres a list of some of the biometrics you can derive from highly accurate, motion-tolerant PPG:
You can see below a simplified PPG signal and where each of the biometrics is measured within that signal.
Read this: How Accuracy Happens in Biometric Wearables and Why It Matters
How To Check Your Heart Rate
You can check your heart rate any time using the Heart Rate app. Open the app, then wait for Apple Watch to measure your heart rate. You can also view your resting, walking, breathe, workout, and recovery rates throughout the day. To easily open the app, add the Heart Rate complication to your watch face or add the Heart Rate app to the Dock.
You can also turn on heart rate notifications, so you know if your heart rate remains above or below a chosen beats per minute , or to occasionally check for an irregular heart rhythm.
Irregular rhythm notifications are available only with watchOS 5.1.2 or later. To enable irregular rhythm notifications, the notifications must be available in your country or region and you must be in the country or region where you purchased your device. Learn where irregular rhythm notifications are available.
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Cons Of Optical Heart Rate Tracking
There are none.
Just kidding. Like we said in the beginning, what you want to do affects how you should do it.
Heres a seemingly bold statement from the pioneers of wearable sports technology : optical heart rate tracking is more prone to errors than chest-strap based heart rate.
Before you call the press , heres what that means: its easier to get erroneous measurements from an optical heart rate sensor than it is to get erroneous measurements from a chest strap HR sensor. There are ways you can cheat an optical heart rate sensor for whatever reason simply by constricting blood flow to the measurement location. And even if youre not consciously trying to confuse the OHR sensor, there are occasions during which you might do so inadvertently .
The key point here is that the sensor should be touching your skin and it shouldnt be moving about much.
Another possible source of error is as usual ourselves. You can get bad results simply by wearing it in a suboptimal position, also known as wearing it wrong.
If youre wearing a wrist-based optical heart rate tracker, like a sports watch, it should be worn snugly behind the wrist bone, towards your elbow . See picture for placement.
If youre wearing Polar Verity Sense, you should wear it on your lower or upper arm for the best results. The key point here is that the sensor should be touching your skin and it shouldnt be moving about much.
Ecg Heart Rate Measurement: Make Accurate Cardiograms
Smartwatches with an ECG heart rate sensor often also have an optical heart rate monitor. The big advantage of an ECG sensor is that it monitors your heart rate even more accurately. With an ECG sensor, you can make cardiograms that show you whether your heart rate is calm or irregular. If the sensor detects an irregular heart rate, it will send you a notification. This way, you have enough time to take action, for example by going to the doctor. In addition, you also have the advantages of a regular optical heart rate sensor.
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