heartRateVariabilitySDNN
A quantity sample type that measures the standard deviation of heartbeat intervals.
Declaration
static let heartRateVariabilitySDNN: HKQuantityTypeIdentifierDiscussion
These samples use time units (described in HKUnit) and measure discrete values (described in HKQuantityAggregationStyle).
HealthKit calculates the Heart rate variability (HRV) by measuring the variation between individual heartbeats. While there are multiple ways of computing HRV, HealthKit uses SDNN heart rate variability, which uses the standard deviation of the inter-beat (RR) intervals between normal heartbeats (typically measured in milliseconds). The system automatically records samples on Apple Watch.
Topics
Metadata
See Also
Vital signs
heartRatelowHeartRateEventhighHeartRateEventirregularHeartRhythmEventrestingHeartRateheartRateRecoveryOneMinuteatrialFibrillationBurdenwalkingHeartRateAverageHKDataTypeIdentifierHeartbeatSeriesHKElectrocardiogramTypeoxygenSaturationbodyTemperaturebloodPressurebloodPressureSystolicbloodPressureDiastolic