Here’s What All Your Apple Watch Health Trackers Actually Do

WatchOS 8 brings even more features.

A woman runs while her Apple Watch tracks her workout and heart rate. All the health trackers on you...
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Whether you’re a biker, Pilates fiend, or couch surfer, you’re probably at least a little familiar with the rings on your Apple Watch, a hallmark of the device since it came out in 2015. But those three recognizable rings are far from the only health trackers on your watch. There are over 20 wellness and fitness trackers you can play with on that compact device on your wrist.

What’s more, in WatchOS 8 and iOS 15, which were released for download on Sept. 20, users got two new features to stay on top of their health: Trends and Health Sharing. Trends chart your wellness data over weeks and months to highlight potential patterns, while Health Sharing lets you send your health info to your contacts or doctor.

Dr. Sumbul Desai, M.D., Apple’s vice president of health, tells Bustle that the new Trends and Health Sharing features are designed to empower users “to be engaged and educated about your health.”

“This is just another way for an individual to share more information with their doctor,” Desai says. “We want to make sure you're having a rich conversation [with your doctor] so that you can share the key things that go on in your life that you may actually not think are important, but really are helpful.”

The idea is that these health trackers can identify possible weirdnesses — say, an unusually high resting heart rate — and then bring that exact info to your doctor to figure out if you need treatment. But doctors caution that trying to understand this data on your own can be confusing.

“I do think it's valuable that these devices are creating patient engagement, that patients are taking more interest in their health,” says Dr. Neel Chokshi, M.D., associate professor of clinical medicine at the University of Pennsylvania and director of Penn Medicine’s Center for Digital Cardiology. He’s seen patients catch health abnormalities like atrial fibrillation on their watches during lockdown, when many Americans put off seeing the doctor.

That said, plain old data “is probably not going to be valuable” out of context for patients or clinicians, he says. Suppose you notice your heart rate is pretty high; you might worry that something’s wrong. But if you were exercising, Chokshi says, then you’re probably fine — unless you’re also experiencing other symptoms. “There’s a lot of potential to improve patients’ health and to serve as a diagnostic tool,” Chokshi notes, adding that these devices need to be paired with clinical context to be genuinely useful.

TL;DR? A watch can’t replace a routine doctor’s visit, but health trackers can give you and your provider useful info — especially over time. Read on to learn how the many, many health trackers on the Apple Watch work.

For Keeping Tabs On Your Internal Health

Heart Rate: Your Apple Watch measures your heart rate with an optical heart sensor that flashes LED lights hundreds of times per second, calculating your heart rate when you’re resting, walking, or exercising. Most healthy adults have a resting heart rate between 60 to 100 beats per minute; the lower, the more protection against heart disease. While exercising, your heart rate should top out at 76% of your maximum heart rate — which, per the CDC, you can calculate by subtracting your age from 220 (so 195 if you’re 25) — during moderate activity or 93% for more intense activity. Your watch also tracks heart rate variability (HRV), or the difference in time between each heartbeat. A doctor can use HRV for insight into your stress reactions and cardiovascular fitness.

ECG App: With the Apple Watch Series 4 or later, you can take your own electrocardiogram (ECG/EKG) on your watch. There are a few possible results you could get: sinus rhythm (meaning everything’s normal), inconclusive or poor recording (the results couldn’t be classified properly), low or high heart rate, or atrial fibrillation (which implies irregular rhythm or rate, and that you should see your doctor). The goal of the ECG app is to alert users to an irregular heartbeat, which could be a sign of atrial fibrillation. But if you have concerns about your heart health, or if you’re experiencing symptoms like chest tightness or unusual fatigue, you should visit your doctor as soon as possible.

Oxygen Saturation: With the Apple Watch Series 6 or later, you can use the Blood Oxygen app to see how much oxygen your red blood cells are transporting around your body. This figure typically falls between 95 and 100%. Below that, it doesn’t always mean you need to worry — just as you would with the ECG feature, talk to your doctor if you have any concerns and make note of any other symptoms.

Cycle Tracking: The menstrual cycle tracking feature on your Apple Watch uses self-reported data like flow level, PMS symptoms, and dates of past periods to offer data and predictions about upcoming periods and fertility.

For Maintaining A Healthy Environment

Automatic Handwashing Detection: Washing your hands with soap and water for at least 20 seconds is one of the best ways to protect yourself from getting sick. To help, the Apple Watch introduced automatic handwashing detection in 2020. If you turn on this feature, your watch uses audio and motion sensors to detect that you’ve started washing your hands, and buzzes when 20 seconds are up.

Noise App: The Noise app on your Apple Watch uses a microphone to assess nearby noise levels. Your watch will send you notifications if it detects a decibel level high enough to harm your hearing — say, if you finally snagged those front-row Phoebe Bridgers tickets — suggesting it’s time to put in earplugs.

Fall Detection: If you have an Apple Watch Series 4 or later, your watch can detect if you’ve taken a hard fall — and if you have WatchOS 8, that includes while biking — and prompt an alert. If you don’t move for at least a minute, your watch will automatically contact emergency services and notify selected contacts.

For Meeting Your Workout & Wellness Goals

Sleep App: The sleep app on your watch lets you manage your bedtime schedule. You can set goals for how many Zzz’s you want to get, log sleep and wake-up times, set alarms, and turn off distractions. If you have an Apple Watch Series 3 or later running WatchOS 8, you can track your breaths per minute while you sleep. According to Healthline, a typical rate falls between 12 to 20 breaths per minute. If you notice that you’re consistently outside that range, you’ll want to talk to your doctor.

Cardio Fitness: This feature estimates your VO2 max, which is the maximum rate of oxygen your body can consume during exercise, based on your workout data and info you give the watch. If you get a notification that your VO2 max is low, you can likely improve it over time with more frequent and intense cardio workouts. According to Healthline, a healthy VO2 max depends on several factors, including age, fitness level, and even elevation.

Mindfulness: WatchOS 8 takes “Breathe” sessions to the next level with the redesigned Mindfulness app. In this app, you can “Reflect” — which prompts you to focus on a specific theme for one minute — or “Breathe,” which is what it sounds like. Once you’re done, you’ll be able to view your heart rate from the session. Trends will track how many minutes you spend on mindful sessions over time to help you integrate more mindfulness into your routine.

Workouts: You can log more than 15 different types of workouts on your watch, like running, yoga, or, with WatchOS 8, Pilates and tai chi. Your watch tracks distance, pace, heart rate, elevation, and calories burned during different workouts. There are also workouts specific to wheelchair users. If you don’t see your favorite workout listed, whether it’s wheelchair basketball or table tennis, you can log it under “other.”

Active Energy: This feature tracks the number of calories you burn during periods of activity, which will help you close your red Move ring. You can set your Move ring yourself, based on your personal fitness goals, and adjust it at any time.

Exercise Minutes: The green Exercise ring on your watch logs how many minutes you spend working out each day. While you’re trying to earn minutes toward your daily exercise goal — which you can set yourself and change at any time — your Apple Watch uses your cardio fitness levels to assess the intensity of your activities. If your movements correspond to at least a brisk walk — or brisk pushes in a wheelchair — then they will count toward closing this ring.

Stand Hours: The blue Stand ring is the last ring on your Apple Watch. To earn an hour toward your daily Stand goal — which you set yourself, just like your other rings — you need to stand up and move around for at least one minute per hour. For wheelchair users, the Stand ring becomes a Roll ring.

Step Count & Flights Climbed: As you try to close your rings every day, you can also check your daily activity on your watch. This feature tells you how many steps you’ve taken and flights of stairs you’ve climbed, and you can track improvement over time in Trends.

Wheelchair Pushes & Distance: If you use a wheelchair, you can turn on the wheelchair setting in your watch’s accessibility options. Your watch and iPhone will log pushes instead of steps, and you’ll also have access to wheelchair-specific workouts. These workouts also document different speeds, terrains, heart rate, and distance.

Distance Walking & Running: You can see how much distance you’ve traveled during a workout by logging an indoor or outdoor walk or run. Once you’re done, you’ll see how much distance you’ve traveled and a map of your workout on the Health app on your iPhone.


Dr. Sumbul Desai, M.D., Apple’s vice president of health

Dr. Neel Chokshi, M.D., associate professor of clinical medicine at the University of Pennsylvania and director of Penn Medicine’s Center for Digital Cardiology