Live heart rate record time interval - WatchOS - swift

Question

I have created a watch app with live heart rate record, for that i have used the workout session and HKAnchoredObjectQuery to fetch the results. In this apple has mentioned that, every 5 seconds will update the heart rate value, but in my case it will take upto 5-10 sec to update. I am using watch serious 3 and i need to collect the value for exactly every 5 seconds.
func startWorkout() {
if (session != nil) {
return
}
let workoutConfiguration = HKWorkoutConfiguration()
workoutConfiguration.activityType = .walking
workoutConfiguration.locationType = .outdoor
do {
session = try HKWorkoutSession(healthStore: healthStore, configuration: workoutConfiguration)
session?.delegate = self
} catch {
print("Unable to create the workout session!")
}
session?.startActivity(with: Date())
}
func startHeartRateStreamingQuery(_ workoutStartDate: Date){
guard let quantityType = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier.heartRate) else { return nil }
let datePredicate = HKQuery.predicateForSamples(withStart: workoutStartDate, end: nil, options: .strictEndDate )
let predicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate])
let heartRateQuery = HKAnchoredObjectQuery(type: quantityType, predicate: predicate, anchor: nil, limit: Int(HKObjectQueryNoLimit)) { (query, sampleObjects, deletedObjects, newAnchor, error) -> Void in
self.updateHeartRate(sampleObjects)
}
heartRateQuery.updateHandler = {(query, samples, deleteObjects, newAnchor, error) -> Void in
self.updateHeartRate(samples)
}
healthStore.execute(heartRateQuery)
}
func updateHeartRate(_ samples: [HKSample]?) {
guard let heartRateSamples = samples as? [HKQuantitySample] else {return}
for sample in heartRateSamples {
let timeStamp = sample.startDate
let value = sample.quantity
print("\(timeStamp)_\(value)")
}
}