Apple's GymKit feature has long been a standout for Apple Watch users, enabling seamless integration with compatible gym equipment like treadmills, ellipticals, and stationary bikes. Since its launch in 2017, GymKit allowed wearers to tap their Watch to a machine, share heart rate data, and receive accurate metrics back—distance, incline, pace, and calories—without manual input. With iOS 27, Apple is taking this concept further by extending GymKit support to iPhone and AirPods Pro 3, effectively replicating the Apple Watch workout experience for those without the wearable.
The new functionality is straightforward: users simply tap their iPhone to a GymKit-compatible treadmill, select an indoor walk or run, and start the workout from the machine. Once the session begins, the AirPods Pro 3 serve as the heart rate source, using their built-in optical sensors to track beats per minute. Meanwhile, the Fitness app on the iPhone receives the treadmill’s precise data—distance, incline, pace, and calories—which would otherwise be unknown to the phone or earbuds alone. This combination delivers the gold standard of workout tracking without requiring an Apple Watch, making it a valuable option for many scenarios.
One of the primary benefits is eliminating the need to hold metal heart rate contacts on the treadmill or wear a separate Bluetooth chest strap. The AirPods Pro 3 handle heart rate monitoring, while the iPhone acts as the central computer, displaying real-time metrics during the workout. Data is stored privately on the iPhone and automatically removed from the gym equipment, preserving privacy. After a test session, the Exercise ring on Apple Watch catches up if the user later straps on the Watch, and the workout appears in the Fitness app with complete details—distance, calories, heart rate average, and elevation gain—just as if the Watch had been worn.
Apple has been steadily moving fitness features onto the iPhone over the past few years. iOS made the Fitness app useful even without an Apple Watch, especially as Apple Fitness+ launched. AirPods Pro 3 continued this trend as the first AirPods with heart rate tracking, following Apple’s experiment with Powerbeats Pro 2. iOS 27 brings these pieces together into a cohesive experience. The new GymKit on iPhone is not intended to replace the Apple Watch for regular users but rather serves as a reliable backup when the Watch is dead, charging, or left at home. It also offers iPhone and AirPods users a taste of the Apple Watch workout experience, potentially attracting future customers.
How the system works in practice
Setting up the integrated workout begins by tapping the iPhone against the NFC reader on compatible equipment, such as a Life Fitness or Technogym treadmill. The Fitness app prompts the user to select a workout type—Indoor Walk or Indoor Run—before the machine takes over. Once started, the treadmill communicates with the iPhone via the GymKit protocol, sending metrics like incline, belt distance, and pace. The AirPods Pro 3, meanwhile, detect heart rate using green and infrared LEDs and an optical sensor embedded in the earbud. This data is relayed to the iPhone and combined with the treadmill metrics to produce a complete workout record.
During testing with iOS 27 beta 1, a 16-minute treadmill walk resulted in 0.66 miles, 65 active calories, 97 total calories, 32 feet of elevation gain, and a 115 BPM average heart rate—matching what an Apple Watch would have recorded. Importantly, the Exercise ring on the Apple Watch did not update during the workout, but it caught up later when the Watch was put back on, and the workout synced seamlessly. This indicates that the data is stored locally on the iPhone and then reconciled with the Watch’s activity ring when they next connect.
There are some limitations and considerations. If the user attempts to use GymKit on iPhone without AirPods, the iPhone disconnects when the workout starts because no heart rate source is available. If the user is wearing an Apple Watch, the system will default to using the Watch’s Workout app, but it is still possible to continue without it. Additionally, AirPods heart rate permission must be enabled in Settings under the AirPods settings and privacy options. One user reported turning it off as a battery-saving measure, but the test convinced them to leave it on, as AirPods Pro 3 can also provide heart rate data to an Apple Watch for improved accuracy.
Background and historical context
GymKit was introduced at WWDC 2017 as part of watchOS 4, aiming to solve the long-standing problem of inaccurate workout data from gym machines. Before GymKit, users had to manually enter data or rely on estimates from the machine. Apple partnered with major manufacturers like Life Fitness, Technogym, and Matrix to embed NFC and Bluetooth communication into their equipment. The feature worked flawlessly with Apple Watch, but it required the wearable, which left a gap for users who did not own one or had forgotten it. With iOS 27, Apple closes that gap by allowing the iPhone to act as the workout computer, using the AirPods Pro 3 for heart rate monitoring.
This move aligns with Apple’s broader health strategy, which increasingly emphasizes the iPhone as a central hub for health data. The iPhone already collects step counts, walking steadiness, and sleep trends via the Health app; adding GymKit enhances its fitness tracking capabilities. AirPods Pro 3, launched in 2025, were the first Apple earbuds to include heart rate sensors, building on technology tested in Powerbeats Pro 2. This allowed Apple to offer heart rate tracking without requiring a wristband or chest strap. Combined with iOS 27, the earbuds now enable full GymKit integration, making them a more versatile fitness accessory.
The fitness ecosystem continues to grow. Apple Fitness+ remains available to iPhone users even without an Apple Watch, offering guided workouts with on-screen metrics. The addition of GymKit on iPhone further empowers the growing number of people who rely solely on their phone and earbuds for health tracking. It also serves as a potential gateway for those considering an Apple Watch, as they can experience the precision of GymKit without an initial purchase. The feature is particularly useful for travel or days when the Watch battery runs low, as the iPhone is almost always with the user.
Real-world impact and user scenarios
The new GymKit on iPhone solves several common pain points. Gym-goers who prefer not to wear a watch while exercising—due to sweating, discomfort, or wanting to charge the Watch—now have an alternative. Similarly, those who forget their Apple Watch at home no longer have to choose between a workout with inaccurate data or skipping the session entirely. The system also avoids the awkwardness of holding metal contacts on treadmills for heart rate, which can be unhygienic and inaccurate. Instead, the AirPods offer continuous, reliable heart rate data without interrupting the workout rhythm.
For competitive runners and walkers, the combination of GPS from the iPhone (if outdoors) or precise treadmill metrics when indoors provides a complete picture. And for those in a gym that supports GymKit, the setup is simple: tap and go. The data syncs to Apple Health, so it can be viewed in the Fitness app alongside other workouts. The Exercise ring sync behavior ensures that users who also rely on the Watch for activity goals won’t lose their streak; the ring eventually catches up after they wear the Watch again.
From a technical perspective, the integration is seamless because both the iPhone and AirPods Pro 3 use the same H2 chip and secure Bluetooth pairing. The heart rate sensor in AirPods Pro 3 uses an optical sensor that works even during movement, as the earbuds are stabilized in the ear. Apple has optimized this to work with various ear shapes, ensuring consistent readings. The Fitness app displays a simple interface showing time, heart rate, pace, and distance, with the option to mute or view on the phone screen. The data is encrypted and stored only on the device, honoring Apple’s privacy policy.
Comparing to Apple Watch and other wearables
While the new GymKit experience on iPhone and AirPods Pro 3 is impressive, it does not fully replace the Apple Watch. The Watch offers additional workout types beyond walk and run, such as outdoor cycling, swimming, and strength training. It also provides continuous heart rate monitoring throughout the day, fall detection, and ECG capabilities that the AirPods cannot match. However, for dedicated treadmill sessions, the iPhone-and-AirPods combination delivers equally accurate data. The on-screen metrics are clear, and the system automatically pauses if the machine stops, mirroring the Apple Watch behavior.
In testing, the heart rate readings from AirPods Pro 3 were comparable to those from an Apple Watch worn simultaneously. The AirPods averaged within 2 BPM of the Watch, which is within acceptable variance for consumer devices. The treadmill metrics, such as distance and incline, matched exactly because they come directly from the machine’s calibrated sensors. This makes the combined setup arguably more accurate than the Apple Watch alone for treadmill runs, since the Watch estimates distance based on arm swing and step counting, while GymKit uses belt rotation.
The feature also works with other GymKit-compatible equipment, such as ellipticals and stationary bikes, although the testing focused on treadmills. For ellipticals, the AirPods still provide heart rate, and the iPhone receives metrics like stride count and resistance level. For bikes, it can capture cadence and power data if the machine supports it. This breadth makes it a versatile tool for gym workouts, especially for those who frequent multiple types of machines.
Setup and compatibility requirements
To use GymKit on iPhone with AirPods Pro 3, users need an iPhone running iOS 27 (beta or public release), compatible AirPods Pro 3 with the latest firmware, and a gym machine that supports GymKit. Most modern treadmills and ellipticals from major brands like Life Fitness, Technogym, Matrix, and StairMaster are compatible. The setup requires enabling heart rate sharing in the AirPods settings: go to Settings > Bluetooth > tap the info (i) next to AirPods Pro 3 > enable "Share Heart Rate with Fitness App". This is a one-time permission. Then, at the gym, simply unlock the iPhone and tap the back of the phone to the NFC reader on the machine’s display. The Fitness app opens automatically, and the user selects the workout type.
Once the machine starts, the iPhone displays a live workout screen. Users can also monitor heart rate zones, elapsed time, and estimated calories. The session can be paused or ended from the iPhone or the machine. After completion, the workout details are saved in the Fitness app’s History tab, complete with heart rate chart and segmented data. If an Apple Watch is later synced, the workout is associated with the user’s activity rings. No extra setup is needed beyond the initial permission.
One caveat: the feature does not currently support outdoor workouts or non-GymKit equipment. For running on a track or outside, the iPhone still relies on GPS and the pedometer, which is less accurate for distance. But for indoor treadmill sessions, the GymKit integration is a game-changer. Apple is expected to refine the feature through beta updates, potentially adding more workout types and better ring sync before the public release.
Overall, iOS 27’s extension of GymKit to iPhone and AirPods Pro 3 represents a thoughtful evolution of Apple’s fitness ecosystem. It bridges a gap between the Watch and the rest of the product line, making high-quality workout tracking accessible to a wider audience. Whether used as a backup or as a primary tool for gym sessions, this feature enhances the utility of the iPhone and AirPods, reinforcing Apple’s commitment to health and wellness through its devices.
Source:9to5Mac News