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On your iPhone, open Health > Browse > Heart > Cardio Fitness to find your Apple Watch VO₂ max estimate. Read the number alongside its age- and sex-based category and its trend over time: it is an estimate, not a laboratory measurement or diagnosis.
What Apple Watch Cardio Fitness measures
Cardio Fitness is Apple’s estimate of VO₂ max: the maximum amount of oxygen your body can consume during exercise. Apple Watch uses heart and motion sensor data recorded during supported outdoor workouts to estimate it. Apple documents an estimate range of 14–65 mL/kg/min; that is the feature’s supported range, not a target or a universal health cutoff. Apple Support explains the estimate and its range.
The feature is available on Apple Watch Series 3 or later. It uses workouts recorded in the Workout app: Outdoor Walk, Outdoor Run, or Hiking. Indoor workouts, including workouts on gym equipment, do not contribute. Apple also says push workouts are not supported.
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- Open Health on your iPhone. Tap Browse. On iPad, use the sidebar instead.
- Tap Heart > Cardio Fitness.
- Choose D, W, M, 6M, or Y to view a day, week, month, six months, or year.
- Tap Show All Cardio Fitness Levels to view the available levels, then select one to compare results in the age- and sex-based groupings.
Apple also offers average levels for Female, Male, or All. The available views and comparison options are described in Apple’s Cardio Fitness instructions.
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- A FULL-FEATURED HEALTH TRACKER—Apple Watch Series 11 gives you invaluable insights about your body, right from your wrist. Take an ECG anytime* and get alerts for a high and low heart rate or an irregular rhythm*—so you can stay closer to your heart. You can also view your overnight health tracking metrics with the Vitals app* and be notified of possible sleep apnea.*
- KNOW YOUR SLEEP SCORE—With advanced sleep tracking, Series 11 gives you a daily sleep score. It’s an easy way to help measure and understand the quality of your sleep, so you can make it more restorative.
- GET HYPERTENSION NOTIFICATIONS—Did you know that Series 11 can spot signs of chronic high blood pressure? By analyzing how your blood vessels respond to beats of the heart, it can notify you of possible hypertension.*
- SAFETY FEATURES—A smartwatch that puts your safety first. Series 11 can detect a hard fall or severe car crash, automatically help connect you with emergency services, and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
What the number and category tell you
Health displays a VO₂ max estimate and a category: Low, Below Average, Above Average, or High. The comparison is based on age and sex; Apple says classifications are available to users aged 20 or older. Apple also takes age, sex, weight, height, and medications that can affect heart rate into account.
For personal tracking, look at the pattern across weeks or months as well as the category, rather than treating one reading as a verdict. Apple’s cited support guidance does not establish a universal clinical cutoff for an individual, and its categories are not a substitute for individualized medical assessment. The displayed value is an estimate, not a direct laboratory measurement.
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- A FULL-FEATURED HEALTH TRACKER—Apple Watch Series 11 gives you invaluable insights about your body, right from your wrist. Take an ECG anytime* and get alerts for a high and low heart rate or an irregular rhythm*—so you can stay closer to your heart. You can also view your overnight health tracking metrics with the Vitals app* and be notified of possible sleep apnea.*
- KNOW YOUR SLEEP SCORE—With advanced sleep tracking, Series 11 gives you a daily sleep score. It’s an easy way to help measure and understand the quality of your sleep, so you can make it more restorative.
- GET HYPERTENSION NOTIFICATIONS—Did you know that Series 11 can spot signs of chronic high blood pressure? By analyzing how your blood vessels respond to beats of the heart, it can notify you of possible hypertension.*
- SAFETY FEATURES—A smartwatch that puts your safety first. Series 11 can detect a hard fall or severe car crash, automatically help connect you with emergency services, and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
If no estimate appears
An initial estimate may take time. Apple says you may need to wear the watch for at least 24 hours, complete several supported outdoor workouts, and allow passive measurements before a result appears. Record an Outdoor Walk, Outdoor Run, or Hiking workout in the Workout app; an indoor workout will not generate this estimate.
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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Check that your Health profile details are current and that the watch sits snugly on top of your wrist during a workout. Apple says a good fit helps the sensors work and recommends choosing the workout type that best matches your activity. See Apple’s setup and measurement guidance.
Rank #3
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- GET SMARTER HEALTH INSIGHTS—Apple Watch SE 3 is an advanced health tracker that helps you better understand your body. The smartwatch sends alerts for an irregular heart rhythm, or an unusually high or low heart rate.* You can view your overnight health tracking metrics with the Vitals app,* track your sleep score, and get sleep apnea notifications.*
- A GREAT FITNESS TRACKER—SE 3 can track your workouts in a healthy number of ways—from running and strength training to simply achieving your 10K steps a day. With real-time metrics and Workout Buddy powered by Apple Intelligence from your nearby iPhone,* you’ll hit your goals like never before.
- KEEP HELP CLOSE AT HAND—SE 3 is a smartwatch that can detect a hard fall or severe car crash and automatically help connect you to emergency services and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- WOMEN’S HEALTH INSIGHTS—SE 3 has advanced sensors that track your wrist temperature while you sleep. With this smartwatch, you can log your periods and symptoms, get period predictions, and get notified of cycle deviations.*
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Limitations to keep in mind
Some health conditions or medications that limit heart rate can cause Apple Watch to overestimate VO₂ max. If a result seems inconsistent with how you feel or with other information about your health, do not use the watch category alone to assess your condition. Apple’s cited guidance provides no quantified laboratory-comparison accuracy figure for this estimate.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Manage low-fitness notifications
Apple Watch can notify you when cardio fitness is low for your age and sex. Apple’s watchOS guide says that if the result stays low, another notification may arrive every four months. To manage the setting, open the Watch app on your iPhone and go to My Watch > Apps > Heart, then turn Cardio Fitness Notifications on or off. Apple’s watchOS guide covers the notifications.
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![Apple Watch Series 11 [GPS 42mm] Smartwatch with Jet Black Aluminum Case with Black Sport Band - S/M. Sleep Score, Fitness Tracker, Health Monitoring, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/41s72HIk5TL._SL160_.jpg)
- A FULL-FEATURED HEALTH TRACKER—Apple Watch Series 11 gives you invaluable insights about your body, right from your wrist. Take an ECG anytime* and get alerts for a high and low heart rate or an irregular rhythm*—so you can stay closer to your heart. You can also view your overnight health tracking metrics with the Vitals app* and be notified of possible sleep apnea.*
- KNOW YOUR SLEEP SCORE—With advanced sleep tracking, Series 11 gives you a daily sleep score. It’s an easy way to help measure and understand the quality of your sleep, so you can make it more restorative.
- GET HYPERTENSION NOTIFICATIONS—Did you know that Series 11 can spot signs of chronic high blood pressure? By analyzing how your blood vessels respond to beats of the heart, it can notify you of possible hypertension.*
- SAFETY FEATURES—A smartwatch that puts your safety first. Series 11 can detect a hard fall or severe car crash, automatically help connect you with emergency services, and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- A POWERFUL FITNESS TRACKER—With advanced metrics and motivating features like Pacer, Heart Rate Zones, training load, and Workout Buddy powered by Apple Intelligence from your nearby iPhone*—Series 11 is made to help everyone stay active, from runners and hikers to strength-training enthusiasts.
Rank #4
![Apple Watch SE 3 [GPS 40mm] Smartwatch with Midnight Aluminum Case with Midnight Sport Band - S/M. Fitness and Sleep Trackers, Heart Rate Monitor, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/31Gq8SToFJL._SL160_.jpg)
- GET SMARTER HEALTH INSIGHTS—Apple Watch SE 3 is an advanced health tracker that helps you better understand your body. The smartwatch sends alerts for an irregular heart rhythm, or an unusually high or low heart rate.* You can view your overnight health tracking metrics with the Vitals app,* track your sleep score, and get sleep apnea notifications.*
- A GREAT FITNESS TRACKER—SE 3 can track your workouts in a healthy number of ways—from running and strength training to simply achieving your 10K steps a day. With real-time metrics and Workout Buddy powered by Apple Intelligence from your nearby iPhone,* you’ll hit your goals like never before.
- KEEP HELP CLOSE AT HAND—SE 3 is a smartwatch that can detect a hard fall or severe car crash and automatically help connect you to emergency services and notify your emergency contacts.* Check In can automatically notify a loved one when you’ve arrived at your destination.
- WOMEN’S HEALTH INSIGHTS—SE 3 has advanced sensors that track your wrist temperature while you sleep. With this smartwatch, you can log your periods and symptoms, get period predictions, and get notified of cycle deviations.*
- GREAT BATTERY LIFE AND FASTER CHARGING—Enjoy a smartwatch with all-day, 18-hour battery life* from sunup to sundown. Then charge up to twice as fast as SE 2* and get up to 8 hours of battery in just 15 minutes.*
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