Since its launch in 2017, GymKit has been one of the Apple Watch's smartest fitness features. It allows users to tap their watch to compatible gym equipment, sharing heart rate data from the watch while receiving metrics like distance, incline, pace, and calories from the machine. This seamless integration eliminated the need for manual data entry and improved workout accuracy. However, it required wearing an Apple Watch. Now, with iOS 27, Apple is extending that capability beyond the watch, making GymKit available to iPhone and AirPods Pro 3 users for the first time.
This new functionality essentially gives you the Apple Watch GymKit workout tracking experience without actually wearing the watch. The setup is straightforward: tap your iPhone to the NFC reader on compatible gym equipment—such as a treadmill—select your workout type (like Indoor Walk or Indoor Run), and start the session from the machine. The iPhone handles the workout computer role, while AirPods Pro 3 become the heart rate source. The treadmill provides precise data such as belt distance, incline, and machine-calculated calories, which the iPhone records and displays in the Fitness app. This combination delivers data that a phone or earphones alone could never capture accurately.
One of the most compelling aspects is that all workout data is stored privately on the iPhone and automatically removed from the gym equipment after the session ends, maintaining privacy standards similar to Apple Watch. For users who typically rely on their Apple Watch but find themselves without it—because the battery died, it's charging, or it was accidentally left at home—this feature acts as a powerful backup. It also serves as an enticing preview for current iPhone and AirPods owners who have not yet purchased an Apple Watch, potentially converting them into future customers.
In testing with the iOS 27 beta, the integration proved robust. The treadmill instantly recognized the iPhone tap, and the Fitness app began receiving real-time metrics. AirPods Pro 3 continuously streamed heart rate data, which the system used to calculate active calories and total calories. After a 16-minute treadmill walk, the recorded data showed 0.66 miles, 65 active calories, 97 total calories, 32 feet of elevation gain, and an average heart rate of 115 BPM—identical to what an Apple Watch would have logged. Notably, the Exercise ring on the watch did not update during the workout, but once the user put the watch back on, the ring caught up and the workout appeared in Fitness with all correct information.
How GymKit on iPhone Works Without Apple Watch
The underlying technology is a natural evolution of Apple's fitness ecosystem. iOS has been gradually moving more fitness features onto iPhone, starting with making the Fitness app useful without an Apple Watch for Apple Fitness+ subscribers. AirPods Pro 3 pushed this further by introducing built-in heart rate tracking, following a trial with Powerbeats Pro 2. iOS 27 ties these pieces together into a cohesive experience. The process eliminates two common gym annoyances: holding metal heart rate contacts on the treadmill handlebars and wearing a separate Bluetooth heart rate strap. AirPods Pro 3 handle heart rate monitoring in the background while also serving as the audio source for music or podcasts.
If a user attempts to use GymKit on iPhone without wearing AirPods, the system disconnects at workout start because no heart rate source is available. Similarly, if the user wears an Apple Watch and tries to start GymKit from iPhone, iOS redirects them to the Workout app on the watch, though it still allows continuing without the watch. This intelligent routing ensures the best possible data source is used. AirPods heart rate permissions can be managed in Settings under the AirPods section and privacy options; turning this off can save battery but disables the GymKit integration. Testers found it worthwhile to keep the permission on, as AirPods Pro 3 can also provide heart rate data directly to an Apple Watch for even more accurate readings.
Background and Historical Context
GymKit was introduced alongside watchOS 4 in 2017, initially supported on select Life Fitness, Technogym, and Matrix machines. The protocol uses NFC for initial pairing and Bluetooth for ongoing data exchange. Apple designed it to solve a persistent problem: machine-calculated calories are often inaccurate because they rely on generic formulas that don't account for the user's heart rate, age, weight, or fitness level. With GymKit, the Apple Watch's heart rate data allows the equipment to adjust calorie calculations in real time, making them far more precise. Over the years, GymKit has expanded to thousands of gyms worldwide, including popular chains like Equinox and Planet Fitness. The feature has remained exclusive to Apple Watch until now.
The inclusion of heart rate tracking in AirPods Pro 3 marked a significant step. The sensors use photoplethysmography (PPG) similar to Apple Watch but are positioned in the ear canal, which can sometimes offer comparable accuracy for steady-state exercise. Apple's testing with Powerbeats Pro 2 validated the concept, leading to the AirPods Pro 3 implementation. This hardware capability, combined with iOS 27's software updates, unlocks the GymKit extension. It is a prime example of Apple's ecosystem integration—each device contributes its strengths: the treadmill provides machine data, AirPods provide biometrics, and iPhone acts as the central processor and display.
Comparison to Apple Watch Accuracy
While the iPhone-plus-AirPods combination delivers impressive results, it is not identical to wearing an Apple Watch. Apple Watch has its own motion sensors (accelerometer and gyroscope) that can detect arm swing and pace, which helps calibrate treadmill workouts even without GymKit. With watchOS 27, Apple improved these algorithms further, making Apple Watch treadmill tracking more accurate on its own. However, GymKit still remains the gold standard because it receives direct data from the machine's belt sensors and incline measurement, eliminating estimation errors. For users who prioritize precision, using GymKit with Apple Watch is ideal, but the new iPhone setup comes remarkably close.
One limitation noted in testing is that the Exercise ring on Apple Watch does not update during a GymKit session started from iPhone, even if the watch is worn later. The ring only retroactively updates after the workout ends and the watch syncs with iPhone. This is a minor hiccup for those who rely on ring-closing motivation. Apple may address this in future beta updates or introduce a workaround that allows the watch to passively track movement while the iPhone handles GymKit. Until then, users should plan accordingly if they want real-time ring progress.
Do More with Your Apple Products
The expansion of GymKit is part of Apple's broader strategy to make fitness tracking accessible to a wider audience. By decoupling the experience from the Apple Watch, the company encourages users to explore the fitness features of iOS and AirPods, which may lead to increased adoption of Apple Watch as an upgrade path. It also strengthens the value proposition of AirPods Pro 3, which already offer top-tier audio and noise cancellation. For gyms, it means more members can take advantage of GymKit without needing a watch, potentially increasing usage of connected equipment.
Looking ahead, it is possible that Apple will extend GymKit compatibility to other AirPods models with heart rate sensors, or even to third-party earphones through the Made for iPhone program. The same NFC-based pairing could work with other devices like the iPad or even Apple TV for home gyms. As Apple continues to refine its fitness ecosystem, features like this blur the line between dedicated wearables and everyday devices, offering flexibility and convenience for all types of users.
Source: 9to5Mac News