---
title: peakExpiratoryFlowRate
framework: healthkit
role: symbol
role_heading: Type Property
path: healthkit/hkquantitytypeidentifier/peakexpiratoryflowrate
---

# peakExpiratoryFlowRate

A quantity sample type that measures the user’s maximum flow rate generated during a forceful exhalation.

## Declaration

```swift
static let peakExpiratoryFlowRate: HKQuantityTypeIdentifier
```

## Discussion

Discussion These samples use volume/time units (described in HKUnit) and measure discrete values (described in HKQuantityAggregationStyle).

## See Also

### Lab and test results

- [bloodAlcoholContent](healthkit/hkquantitytypeidentifier/bloodalcoholcontent.md)
- [bloodGlucose](healthkit/hkquantitytypeidentifier/bloodglucose.md)
- [electrodermalActivity](healthkit/hkquantitytypeidentifier/electrodermalactivity.md)
- [forcedExpiratoryVolume1](healthkit/hkquantitytypeidentifier/forcedexpiratoryvolume1.md)
- [forcedVitalCapacity](healthkit/hkquantitytypeidentifier/forcedvitalcapacity.md)
- [inhalerUsage](healthkit/hkquantitytypeidentifier/inhalerusage.md)
- [insulinDelivery](healthkit/hkquantitytypeidentifier/insulindelivery.md)
- [numberOfTimesFallen](healthkit/hkquantitytypeidentifier/numberoftimesfallen.md)
- [peripheralPerfusionIndex](healthkit/hkquantitytypeidentifier/peripheralperfusionindex.md)