GymKit enables two-way synchronization of fitness data between an Apple Watch and gym equipment. In this case, the Apple Watch sends specific calorie and heart rate measurements to the elliptical, and the elliptical forwards metrics like level, distance, and workout duration to the Apple Watch.
At the end of a workout, data from the equipment appears in the Activity app on the user's Apple Watch and iPhone. No data is stored on the Octane machines.
Octane Fitness equipment is available at a variety of gyms and athletic clubs, including select 24-Hour Fitness, Anytime Fitness, Crunch Fitness, Equinox, Gold's Gym, GoodLife Fitness, Life Time Fitness, Retro Fitness, Snap Fitness, UFC Gym, Wellbridge, and YMCA locations, according to its website.
Octane Fitness says its equipment is also used by companies like Facebook and Google, colleges like Duke and Columbia, some NFL and MLB teams, the CIA and FBI, various fire and police departments, and many others.
It will likely take some time for the GymKit-enabled ellipticals to make their way to all of the locations listed above, as gyms and other commercial establishments gradually renew and replace their equipment over time.
GymKit was introduced in watchOS 4.1 in October 2017.