HKCategoryValue Enums by Type

A HealthKit category sample does not hold a measurement. It holds a value drawn from an enumeration, plus a start date and an end date — and that is the entire payload. 30 of the 240 identifiers in this dataset are category types, and the table on this page pairs each of them with the value enum it resolves to. 28 resolve. Two do not.

The distinction that matters when you write the reading code is between a type-specific enum and the generic one. sleepAnalysis resolves to HKCategoryValueSleepAnalysis, menstrualFlow to HKCategoryValueMenstrualFlow, appleStandHour to HKCategoryValueAppleStandHour, contraceptive to HKCategoryValueContraceptive, ovulationTestResult to HKCategoryValueOvulationTestResult, lowCardioFitnessEvent to HKCategoryValueLowCardioFitnessEvent. Each of those carries real alternatives: a sleep sample says which stage, a menstrual flow sample says how heavy, a stand-hour sample says stood or idle. The value is information.

Then there is plain HKCategoryValue, which is what a type resolves to when its value has nothing to say. mindfulSession, handwashingEvent, toothbrushingEvent, sexualActivity, pregnancy, lactation and intermenstrualBleeding all land here, as do the heart-event types highHeartRateEvent, lowHeartRateEvent and irregularHeartRhythmEvent, and the iOS 16.0 cycle-deviation types irregularMenstrualCycles, infrequentMenstrualCycles, persistentIntermenstrualBleeding and prolongedMenstrualPeriods. For these the sample's meaning lives entirely in its type and its time range: these are the .notApplicable types, and reading the value tells you nothing you did not already know from the query you ran. A mindfulSession sample means someone meditated, from here until there. There is no scale.

This is why averaging a category type is not a slightly wrong answer but a category error. The integer you can pull out of a category sample is an ordinal — a position in a list of alternatives — and arithmetic on ordinals produces a number that measures nothing. The mean of a week of menstrualFlow samples is not a flow. The mean of a month of sleepAnalysis values is not a sleep quality. What category data supports is counting occurrences, measuring elapsed time from the start and end dates, taking the latest value, and grouping by value. If you want a number out of a category type, derive it from the dates or from the count, never from the value.

Two category types have no value enum resolved in this dataset: bleedingAfterMenopause and hypertensionEvent. Both are null on purpose. Resolving these took three passes: taking the first HKCategoryValue* symbol mentioned on the page resolved 29 of 30 and was wrong, because a cross-linked symbol on the pregnancy page would have shipped the wrong enum for a type. Requiring an exact name match resolved far fewer and was structurally biased against every type whose value is .notApplicable. The rule that shipped accepts either the type's own matching enum name or the generic enum, which resolves 28 and leaves two honest nulls. A null here means Apple's page did not state it in a form the parser could stand behind — not that no enum exists. That choice, and why guessing the last two would have been worse than admitting the gap, is written up in building the HealthKit dataset.

Everything above was parsed from Apple's developer documentation on 2026-08-28 for the HealthKit identifier dataset. Which of these types are beta or otherwise unsettled is on HealthKit type status. For the two category types most products actually read, see sleep tracking APIs, what sleep stages are and the menstrual cycle API.