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Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →In a company-conducted September 2026 comparison, Apple Watch Series 12 recorded heart rates more accurately overall than Garmin Forerunner 970 against a Polar H10 chest-strap reference. That is the clearest current head-to-head evidence for these two models, but it is not a personal test or an independent replication—and it does not establish that every Apple Watch outperforms every Garmin.
What did the Apple Watch vs. Garmin heart-rate comparison find?
Apple reported that Series 12 had statistically better overall workout and daily-living heart-rate accuracy than Forerunner 970 on both mean absolute error (MAE) and root mean square error (RMSE). The comparison used a Polar H10 ECG chest strap as its reference. The study did not provide a simple standalone MAE figure for the Apple-versus-Garmin headline in its text, so a precise beats-per-minute error should not be inferred from the reported overall result. Apple’s September 2026 study was conducted by Apple, the manufacturer of one of the watches being evaluated.
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The result applies to these exact models and the study’s protocols. It is meaningful direct evidence, but it is not proof that all Apple Watch models are more accurate than all Garmin watches, or that the finding will hold for every wearer and activity.
How was the study conducted?
Apple enrolled 1,460 people; 1,254 contributed at least one paired Apple-versus-comparator measurement. Participants wore an Apple Watch and a comparison wrist device simultaneously, with wrist assignment randomized. The Apple Watch was worn on the dominant wrist about half the time. Devices were fitted snugly according to manufacturers’ guidance, and the Polar H10 supplied the reference heart-rate data.
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![Apple Watch Series 11 [GPS 46mm] Smartwatch with Jet Black Aluminum Case with Black Sport Band - M/L. Sleep Score, Fitness Tracker, Health Monitoring, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/416RQ0rtsUL._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.
Testing took place in July and August 2026 at five sites in California, Texas, and Malaysia. The study included outdoor running at different speeds, indoor interval treadmill running, outdoor cycling, HIIT, strength training, and a daily-living protocol with rest, desk work, meal preparation, and walking. Workout activities lasted 15–20 minutes. Apple analyzed user-facing device data using per-session MAE and RMSE, paired comparisons, and 99% confidence intervals.
Apple reported that 59% of participants enrolled at third-party contract-research sites, 20% of analysis contributors had Fitzpatrick skin tone V or VI, and 35% were female. Mean age was 39 ± 12 years and mean BMI was 26 ± 5 kg/m². People taking beta blockers and people with tattoos or large moles at device sites were excluded. Those exclusions, along with the healthy-adult exercise protocol, limit how confidently the results can be extended to people outside the study population.
Did Apple outperform every comparison watch in every workout?
No. Across all 159 activity-by-measure comparisons, Apple reported a statistically better result in 139, an indeterminate result in 18, and a better result for the comparison device in 2. The point estimates favored Apple in 155 of the 159 comparisons. For session-average heart rate, Apple reported better accuracy in 11 of 12 overall comparisons; the exception was Huawei Watch 5 during workouts, where Apple’s numeric result was better but not statistically significant. For individual workouts, Apple reported better MAE and RMSE in all activity-device comparisons except Pixel Watch 4 during cycling, where the result was indeterminate. These figures span all comparator devices in the study, not just Garmin.
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![Apple Watch Series 11 [GPS 42mm] Smartwatch with Rose Gold Aluminum Case with Light Blush Sport Band - S/M. Sleep Score, Fitness Tracker, Health Monitoring, Always-On Display, Water Resistant](https://m.media-amazon.com/images/I/31caPPnRysL._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.
What does older independent evidence say?
A prospective 2019 study of 50 healthy athletic adults compared Apple Watch III, Garmin Vivosmart HR, Fitbit Ionic, and TomTom Spark 3 during treadmill running at six speeds. A three-lead ECG and Polar H7 chest strap served as references. The study reported ECG concordance of 0.96 for Apple Watch III and 0.89 for Garmin Vivosmart HR; Polar H7’s concordance was 0.98. Accuracy fell at high intensity. This is independent evidence for the older models tested, not a validation of Series 12 against Forerunner 970. The 2019 Journal of Sports Sciences study concluded that a chest strap or Apple Watch may be the best choice for endurance athletes and coaches under its protocol.
A 2025 living systematic review and meta-analysis of Apple Watch validation studies found pooled heart-rate limits of agreement of about −7.19 to 6.64 bpm across all conditions. Its exploratory subgroup for third-generation optical sensors—Series 6 onward, including Ultra—reported narrower limits, −3.68 to 2.59 bpm, based on eight studies. These pooled estimates combine varied protocols and reference methods; they are not a direct comparison of Series 12 and Forerunner 970. The review also notes that many included devices were discontinued. Read the review in npj Digital Medicine.
A 2026 validation study of other wearable models also found that accuracy differed by device and activity, with intermittent walking increasing error for multiple devices. Its tested climate conditions did not significantly affect accuracy under that study’s protocol. It did not include either Series 12 or Forerunner 970, so it offers context about activity effects rather than a verdict on these models. See the 2026 wearable validation study.
Rank #3
![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.
Why can wrist heart-rate readings differ from a chest strap?
Apple’s optical heart sensor uses photoplethysmography: green LEDs illuminate the wrist, and light-sensitive photodiodes detect changes in blood flow. The watch estimates heart rate from those signals. Apple lists an optical heart-rate range of 30–210 beats per minute and cautions that a reliable reading is not available every time for every person. Series 4 and later and all Ultra models also have electrical electrodes for the Heart Rate and ECG apps, but that is distinct from continuous optical monitoring during exercise. Apple explains its heart-rate sensors and readings here.
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Fit, movement, exercise type, and how quickly heart rate changes can all matter to a wrist reading. A steady run and rapid intervals do not present the same measurement conditions; cycling, lifting, and HIIT can also produce different results. A session average can look close to a reference even when some moment-to-moment readings differ, so point-by-point performance and session-average accuracy are not interchangeable.
There is also a difference between accuracy and availability. Apple’s 2024 technical paper says Apple Watch algorithms prioritize accuracy over availability and may withhold readings when sensor signals do not support a reliable result. A gap in displayed data therefore does not show that the watch measured a specific incorrect value; it may mean the algorithm did not report a value. Reporting intervals also differ by device, and Apple’s 2026 study analyzed what each product presented to users. Apple’s technical paper describes its heart-rate algorithms.
Rank #4
![Apple Watch Ultra 3 [GPS + Cellular 49mm] Running & Multisport Smartwatch w/Rugged Titanium Case w/Blue/Bright Blue Trail Loop - M/L. Satellite Communications, Advanced Health & Fitness Tracking](https://m.media-amazon.com/images/I/51SKumOyv8L._SL160_.jpg)
- RUGGED AND READY TO GO—The ultimate sports and adventure smartwatch is built to last with an extremely tough titanium case and a strong sapphire crystal display. Water resistant up to 100m—it’s great for swimmers, divers, and fans of high-speed water sports.*
- A FULL-FEATURED HEALTH TRACKER—Ultra 3 can take an ECG* and check your heart rhythm for signs of AFib—right from your wrist. The smartwatch sends alerts for possible hypertension,* 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 take readings of your blood oxygen.*
- ULTIMATE RUNNING AND WORKOUT COMPANION—A superior fitness tracker for marathoners, triathletes, mountain bikers, backcountry hikers, and mountain climbers, Ultra 3 provides precision dual-frequency GPS, Pacer, Heart Rate Zones, Custom Workouts, running power, Workout Buddy powered by Apple Intelligence from your nearby iPhone,* training load, and more.
- KEEP HELP CLOSE AT HAND—Ultra 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.
- MULTIDAY BATTERY LIFE—Ultra 3 is a smartwatch that’s engineered to give you even longer battery life. It’s perfect for trail runners—with up to 42 hours of normal use and up to 72 hours in Low Power Mode.* Track a workout with full GPS and heart rate monitoring for up to 20 hours in Low Power Mode.*
Should you use a chest strap instead of wrist heart rate?
If you need a closer ECG-based reference for structured training, a chest strap is a reasonable option; Apple’s current comparison itself used the Polar H10 as its reference, and the older athlete study found the Polar H7 closest to ECG among the devices it tested. That does not make a strap necessary for every workout. A wrist watch is more convenient for everyday tracking, while a strap may be worth considering when you care about training data and want a separate reference source.
For choosing between the two current watches, the most accurate reading of the evidence is: Apple’s 2026 company-conducted comparison favors Series 12 over Forerunner 970 overall, while independent current-model confirmation is not established by the cited studies. Treat either watch’s heart-rate feature as a fitness measurement, not a medical diagnosis.
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