Get Apple watch heartRateVariabilitySDNN realtime?


I am using below function to get heartRateVariabilitySDNN, but its get only once and not calculate realtime like hearbeat does?

func HRVstart() { guard let quantityType = HKObjectType.quantityType(forIdentifier: .heartRateVariabilitySDNN) else { return }

self.healthStore.execute(self.HRVStreamingQuery()) // Create query to receive continiuous heart rate samples. let datePredicate = HKQuery.predicateForSamples(withStart: Date(), end: nil, options: .strictStartDate) let devicePredicate = HKQuery.predicateForObjects(from: [HKDevice.local()]) let queryPredicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate, devicePredicate]) let updateHandler: HKQueryUpdateHandler = { [weak self] query, samples, deletedObjects, queryAnchor, error in if let quantitySamples = samples as? [HKQuantitySample] { self?.HRVprocess(samples: quantitySamples) } } let query = HKAnchoredObjectQuery(type: quantityType, predicate: queryPredicate, anchor: nil, limit: HKObjectQueryNoLimit, resultsHandler: updateHandler) query.updateHandler = updateHandler // Execute the heart rate query. healthStore.execute(query) // Remember all active Queries to stop them later. self.HRVactiveQueries.append(query) } private func HRVStreamingQuery() -> HKQuery { let predicate = HKQuery.predicateForSamples(withStart: NSDate() as Date, end: nil, options: .strictStartDate) let query = HKAnchoredObjectQuery(type: self.heartRateVaribalityType, predicate: nil, anchor: nil, limit: Int(HKObjectQueryNoLimit)) { (query, samples, deletedObjects, anchor, error) -> Void in self.HRVformatSamples(samples: samples) } query.updateHandler = { (query, samples, deletedObjects, anchor, error) -> Void in self.HRVformatSamples(samples: samples) } self.HRVactiveQueries.append(query) return query } private func HRVformatSamples(samples: [HKSample]?) { guard let samples = samples as? [HKQuantitySample] else { return } guard let quantity = samples.last?.quantity else { return } let beats = quantity.doubleValue(for: HKUnit.secondUnit(with: .milli)) let timestamp = samples[0].endDate let newHeartRateVariablity = HeartRateVariablity(timestamp: timestamp, hrv: beats) delegate?.heartRateVariablity(didChangeTo: newHeartRateVariablity) print("HeartRateVariablity: \(beats)") } </li> </ul>



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