Apple's GymKit feature, initially introduced alongside the Apple Watch in 2017, has long been praised for its seamless integration with compatible fitness equipment. By tapping an Apple Watch to a treadmill, elliptical, or bike, users could share heart rate data with the machine while receiving precise metrics like distance, incline, pace, and calories burned. This eliminated the need for manual calibration and provided workout data that was both accurate and private. However, until now, GymKit remained exclusive to Apple Watch users. With the release of iOS 27, Apple is changing that by bringing GymKit functionality to iPhone and AirPods Pro 3, effectively turning a combination of these devices into a capable fitness tracker for the gym.
This expansion marks a significant shift in Apple's fitness ecosystem. For years, the company has been gradually extending fitness-related features to iPhone, even without an Apple Watch. iOS 14 introduced a redesigned Fitness app that allowed users to see their iPhone's motion data, and later updates added support for Apple Fitness+ workouts directly on the phone. The introduction of heart rate monitoring in AirPods Pro 3, following a test with Powerbeats Pro 2, laid the groundwork for this new GymKit implementation. Now, with iOS 27, these pieces come together to form a compelling alternative for those who may not own an Apple Watch or who find themselves without it during a workout.
The setup process for GymKit on iPhone is straightforward, echoing the simplicity of the Apple Watch version. Users simply tap their iPhone against the NFC tag on a compatible piece of gym equipment, such as a treadmill. This triggers a prompt on the iPhone screen, offering workout types like Indoor Walk or Indoor Run. After selecting the appropriate activity, the workout begins from the machine itself. The iPhone then communicates with the equipment over a secure Bluetooth connection, ensuring that all data transmitted is encrypted and stored locally on the device. At the end of the session, the workout summary is saved in the Fitness app, with no residual data left on the equipment.
A crucial component of this new setup is the AirPods Pro 3, which serve as the heart rate source. These earbuds are the first from Apple to include optical sensors capable of measuring heart rate during exercise. When paired with an iPhone running iOS 27, they stream heart rate data directly to the Fitness app, allowing the system to monitor cardiovascular intensity in real time. This eliminates the need for the user to hold onto the metal contact pads commonly found on treadmill handles or wear a separate Bluetooth chest strap. The AirPods Pro 3 also double as an audio source for music, podcasts, or workout instructions, making them a single, convenient accessory for both entertainment and health tracking.
Once the workout is underway, the iPhone becomes the central hub for data collection and display. It receives information from the treadmill—such as distance covered, pace per mile or kilometer, incline percentage, and calorie expenditure—and combines it with the heart rate data from the AirPods. This composite data is then shown on the iPhone screen, with live metrics updating in real time. Users can glance at their phone during the workout to monitor progress, just as they would with an Apple Watch. Importantly, the treadmill’s measurements for distance and incline are far more accurate than any estimation that an iPhone or AirPods could provide on their own, as the machine knows exactly how much the belt has moved and its elevation angle.
Testing of the GymKit on iPhone feature during the iOS 27 beta revealed several nuances. A typical 16-minute treadmill walk recorded 0.66 miles, 65 active calories, 97 total calories, 32 feet of elevation gain, and an average heart rate of 115 beats per minute. These numbers matched what an Apple Watch would have recorded in the same scenario, demonstrating the reliability of the setup. However, one notable limitation emerged: during the workout, the Exercise ring on the iPhone did not update in real time if the user was not wearing an Apple Watch. Instead, the ring only caught up after the watch was put back on and the workout data synced. This indicates that the ring closure logic still relies on the watch’s own motion sensors and algorithms, though the GymKit data eventually integrates correctly.
Another interesting behavior is the interplay between devices. If a user attempts to start GymKit on an iPhone while an Apple Watch is also present and active, the system will default to suggesting the Workout app on the watch. Users can still choose to proceed with the iPhone-based workout, but the default encourages using the watch. Additionally, if no AirPods Pro 3 are available—for example, if the user relies on standard wired headphones or the iPhone’s built-in speakers—the GymKit session will disconnect shortly after starting, as there is no heart rate source. This confirms that AirPods Pro 3 are a mandatory component for the feature to function properly.
Privacy remains a cornerstone of the GymKit experience. Apple emphasizes that all workout data is stored locally on the iPhone and is deleted from the gym equipment after the session ends. There is no need to create an account with the equipment manufacturer or share personal health information. Users can also manage heart rate permissions for their AirPods in the Settings app, under the AirPods settings and privacy options. During testing, it was discovered that if heart rate sharing was turned off—perhaps as a battery-saving measure—the AirPods would not provide data, and the workout would fail. This setting is easily toggled back on, and Apple recommends leaving it enabled for fitness tracking.
The broader implications of this feature extend beyond mere convenience. For Apple, it serves as a potential gateway to attract more customers to the Apple Watch. Users who experience the GymKit-on-iPhone workflow may find the fitness tracking capabilities compelling enough to invest in a watch for continuous monitoring, heart health alerts, and additional sensors like blood oxygen and ECG. For existing Apple Watch owners, the new feature acts as a reliable fallback. If the watch is left on the charger, forgotten at home, or its battery dies before a workout, the iPhone and AirPods Pro 3 can step in and deliver comparable data. This flexibility reduces the friction of missing a workout or losing tracking continuity.
The expansion also underscores Apple’s commitment to making its ecosystem more inclusive. Not everyone wants or can afford an Apple Watch, but many already own an iPhone and perhaps a pair of AirPods. By enabling GymKit without requiring the watch, Apple lowers the barrier to entry for accurate treadmill training. This move aligns with the company’s long-standing strategy of adding health and fitness features to the iPhone, such as step counting, walking steadiness, and cycling cadence, making the phone a capable health hub on its own.
From a technical standpoint, the implementation relies on a combination of NFC for pairing and Bluetooth for data exchange. The NFC handshake is immediate, similar to Apple Pay, and the Bluetooth connection remains active throughout the workout. The iPhone must be unlocked and running the Fitness app or be in proximity to the equipment to establish the link. Once connected, the iPhone displays a simplified workout interface with key metrics. Users can pause or end the workout from either the machine or the iPhone, and the data is saved automatically.
One area where the GymKit-on-iPhone experience differs from Apple Watch is in its reliance on the AirPods for heart rate. The watch has its own optical sensor on the back, which continuously monitors heart rate without requiring any additional device. This makes the watch a more self-contained solution. However, the AirPods Pro 3 have the advantage of being worn in the ears, where they can also detect photoplethysmography (PPG) signals through the skin of the ear canal. This method is potentially less prone to motion artifacts than a wrist sensor during high-intensity activities like running, though both technologies have proven reliable in practice.
The psychological effect of not having to grasp metal handles or wear a chest strap cannot be underestimated. Many gym-goers find these requirements awkward or uncomfortable, especially when trying to maintain a natural running form. GymKit on iPhone, with AirPods providing heart rate, eliminates those distractions entirely. The user simply starts the machine, taps their phone, and begins their workout. This streamlined experience is likely to be welcomed by both fitness enthusiasts and casual exercisers alike.
Battery life considerations are worth noting. AirPods Pro 3 already offer excellent battery life for music listening, but continuous heart rate streaming during a workout will draw additional power. Apple has optimized the sensor to use low energy, but users should be aware that a long gym session may reduce the earbuds’ overall battery. Similarly, the iPhone’s battery will be used for display and data processing, but the impact is minimal for typical workouts lasting under an hour. For longer sessions, using the phone on a cradle or placing it on the treadmill’s accessory shelf could help preserve battery.
Looking ahead, it is plausible that Apple will extend GymKit on iPhone to other types of equipment beyond treadmills. Ellipticals, stationary bikes, and rowing machines are all common in GymKit-equipped gyms. The same core technology—NFC tap, heart rate from AirPods, machine data via Bluetooth—could apply to each. However, for now, the feature is demonstrated with treadmills, and support for other equipment may follow in future iOS 27 updates or subsequent versions.
In the context of Apple’s overall product strategy, this move reinforces the idea that the company views health and fitness as a seamless, integrated experience across devices. The iPhone remains the center of the Apple universe, but wearables like AirPods and the Apple Watch are becoming increasingly essential extensions. By allowing GymKit to function without the watch, Apple acknowledges that the sum of its parts can be greater than any single device. This philosophy is visible in other areas too, such as using an iPhone to set up an Apple Watch, or using AirPods to switch between devices via iCloud.
For consumers who are considering upgrading to AirPods Pro 3 or purchasing an iPhone 18 or later (since the feature is tied to iOS 27 compatibility), GymKit on iPhone adds another compelling reason to invest. It is not a headline-grabbing feature like a redesigned home screen or a new camera system, but it solves a real, everyday problem for fitness users. The ability to walk into a gym with only a phone and earbuds and walk out with a detailed, accurate workout log is a convenience that previous generations could only dream of.
The feedback from beta testers has been largely positive, with many noting the simplicity and reliability of the system. A few have pointed out that the heart rate reading from AirPods can sometimes be delayed by a few seconds compared to the watch, but the overall accuracy remains high. Apple is likely to refine the sensor algorithms in future firmware updates to improve responsiveness. Additionally, the requirement to have AirPods Pro 3 means that owners of earlier AirPods models—which lack heart rate sensors—cannot take advantage of GymKit on iPhone. This may encourage some users to upgrade, though Apple also offers the Powerbeats Pro 2 as an alternative with heart rate capability.
Another subtle benefit is that the workout data captured via GymKit on iPhone is fully compatible with Apple’s Health app and Fitness app. It contributes to your daily activity goals, stores historical data, and can be shared with third-party apps with permission. This stands in contrast to using a generic treadmill that might record calories incorrectly or not sync with Apple Health at all. GymKit ensures that every minute and every calorie is accounted for in the ecosystem you already use.
For those who travel frequently, the feature is especially valuable. A business traveler who forgets their Apple Watch at home can still maintain their workout routine at the hotel gym without losing data continuity. Similarly, a person who only works out occasionally and does not want to invest in a watch can still enjoy a premium tracking experience by leveraging their existing iPhone and AirPods. This democratization of advanced fitness tracking aligns with Apple’s mission to put health tools in more hands.
In testing, the integration with the treadmill was seamless. The machines recognized the iPhone tap instantly and displayed a confirmation message. The workout controls were responsive, and pausing or ending the session from either device worked without issues. The only minor hiccup was when the treadmill’s Bluetooth connection dropped momentarily due to distance—specifically when the user stepped away briefly—but the connection reestablished automatically. Apple recommends keeping the iPhone within arm’s reach to avoid such interruptions.
The security model also deserves praise. GymKit uses encryption and token-based authentication to ensure that no third party can access your health data. The machine does not store any personal information; it merely receives heart rate for real-time display on the console and sends back its own metrics. This is a stark contrast to many smart gyms that require logging into their own platforms and storing data on cloud servers. Apple’s approach preserves user privacy while still enabling rich functionality.
As the fitness industry continues to evolve, with more people working out at home and in commercial gyms, features like GymKit on iPhone will likely become more common. Apple’s early adoption of NFC-based pairing and localized data processing sets a standard that competitors may follow. For now, though, iOS 27 users who own AirPods Pro 3 have a powerful new tool at their disposal. Whether as a primary tracker or a backup, GymKit on iPhone makes the trip to the gym more productive and less reliant on multiple gadgets. The future of fitness tracking is clearly moving toward peripheral devices that complement the phone, and this update is a strong step in that direction.
Source: 9to5Mac News