---
title: HKMetadataKeyVO2MaxValue
framework: healthkit
role: symbol
role_heading: Global Variable
path: healthkit/hkmetadatakeyvo2maxvalue
---

# HKMetadataKeyVO2MaxValue

The maximum oxygen consumption rate during exercise of increasing intensity.

## Declaration

```swift
let HKMetadataKeyVO2MaxValue: String
```

## Discussion

Discussion The system sets this key on lowCardioFitnessEvent samples. It contains the value of the VO2 max measurement that triggered the event. The value of this key is an HKQuantity object with a unit of ml/kg/min. For more information on working with complex units, see unitMultiplied(by:), unitDivided(by:), and init(from:).

## See Also

### Cardio Fitness Keys

- [HKMetadataKeyLowCardioFitnessEventThreshold](healthkit/hkmetadatakeylowcardiofitnesseventthreshold.md)