Xcode – How to get WCSession to continue streaming data after WatchKit app falls asleep?

Make sure you have enabled background mode both in Apple watch and iPhone

Example

And you can try the HKLiveWorkoutBuilderDelegate like this:

extension WorkoutManager: HKLiveWorkoutBuilderDelegate {
    func workoutBuilderDidCollectEvent(_ workoutBuilder: HKLiveWorkoutBuilder) {
        
    }
    
    func workoutBuilder(_ workoutBuilder: HKLiveWorkoutBuilder, didCollectDataOf collectedTypes: Set<HKSampleType>) {
        for type in collectedTypes {
            guard let quantityType = type as? HKQuantityType else {
                return // Nothing to do.
            }
            
            let statistics = workoutBuilder.statistics(for: quantityType)
            
            // Update the published values.
            if workoutState == .running {
                updateForStatistics(statistics)
            }
        }
    }
}