Reputable runs decentralized clinical studies on wearable-derived endpoints. Every study standardizes on a single wearable, worn by every participant, so that measurement is identical across the cohort. This menu sets out every metric we can capture, in plain language, and shows which device delivers it, so you can select the one device that supports the endpoints your study needs.
Apple Health KitGarminOura RingWHOOPFitbit
5
Device platforms
47
Continuous signals
6
Metric families
80+
Study-ready endpoints
1
Unified data model
Every provider is different. The five platforms use different sensors, algorithms, field names and units, and the same metric name can mean different things on different devices. That is why device selection is a design decision made before enrollment opens, and why one device is then used for the entire cohort. Reputable normalizes every platform into a single schema, so endpoint definitions and analysis methods stay consistent from study to study. Where a metric is not delivered directly by a device, we state whether we can derive it and how.
How to read this menu
Each metric below is scored against all five platforms. One symbol per device tells you whether that metric is available, and if so how it reaches your dataset. Symbols are colored by device.
Native
The device measures and reports this directly. No processing on our side.
Derived
Available, but Reputable calculates or unit-converts it from the fields the device does provide.
Not available
This platform does not report the metric. A study needing it should select a different device.
n/r
Not reviewed
Outside the scope of this review round; availability not yet confirmed either way.
88 / 88 metrics
01
Sleep
18
The richest family of metrics across all five platforms and the most common primary endpoint in supplement, device and wellness studies. Every provider reports sleep stages; they differ most in whether they expose the underlying timeline and the overnight cardiovascular signals.
Total sleep time
Minutes actually asleep across the night
Time in bed
Total time between lights-out and final wake
Sleep stages
Minutes in light, deep, REM and awake
Sleep efficiency
Share of time in bed spent asleep
Sleep latency
How long it took to fall asleep
Time awake after falling asleep
Total minutes awake mid-night (WASO)
Awakenings / disturbances
Count of interruptions during the night
Sleep cycles completed
Number of full sleep cycles
Overall sleep score
Device's own 0–100 nightly quality score
Lowest heart rate overnight
Resting HR proxy, a key recovery marker
Average heart rate overnight
Mean HR across the sleep period
Overnight HRV
Autonomic recovery marker; see the HRV design note
Respiratory rate
Average breaths per minute while asleep
Skin temperature change
Nightly deviation from personal baseline
Full stage timeline (hypnogram)
Stage-by-stage record across the night
Overnight HR & HRV timeline
Readings every 5 minutes through the night
Nap detection
Daytime sleep captured separately from the night
30-day stage baselines
Participant's own rolling average per stage
02
Daily activity & movement
16
Day-level totals used for adherence monitoring, covariate adjustment and energy-balance endpoints. Note that WHOOP does not report steps or distance at all. If either is an endpoint, WHOOP is not the right device to build the study on.
Daily step count
Total steps taken across the day
Distance traveled
Meters walked and run over the day
Active calories burned
Energy burned above resting metabolism
Total calories burned
Active plus resting energy expenditure
Resting metabolic burn (BMR)
Baseline calories burned at rest
Floors climbed
Elevation gain expressed as flights
Minutes at low / moderate / high intensity
Time split by activity intensity band
n/r
Sedentary time
Minutes spent inactive while awake
n/r
Device non-wear time
Minutes off the body; our primary wear-compliance signal
n/r
Daily activity score
Device's own 0–100 daily movement score
n/r
Training strain (0–21)
WHOOP's cardiovascular load score for the day
n/r
MET-minutes by intensity
Metabolic-equivalent workload, four bands
n/r
Daily heart rate summary
Min, mean and max HR across the day
n/r
Time in heart rate zones
Minutes in fat-burn, cardio and peak zones
n/r
Inactivity alerts
Count of prolonged sitting prompts
n/r
Goal attainment
Progress against the participant's own targets
n/r
03
Workouts & training sessions
15
Session-level data for exercise, performance and sports-nutrition studies. Every platform records session timing and distance; they diverge sharply on heart rate detail and on how reliably the sport type is labelled.
Session start, end & duration
When the workout happened and how long it lasted
Sport / activity type
What kind of workout it was
n/r
Distance covered
Meters traveled during the session
Calories burned in session
Energy expenditure for the workout
n/r
Average heart rate
Mean HR across the session
n/r
Peak heart rate
Highest HR reached during the workout
n/r
Time in heart rate zones
Seconds spent in each training zone
n/r
Training strain (0–21)
Cardiovascular load for the session
n/r
Perceived intensity label
Easy / moderate / hard classification
n/r
Elevation gain
Meters climbed during the session
n/r
Steps & average speed
Step count and pace within the workout
n/r
Swim stroke count
Strokes recorded in pool sessions
Auto-detected vs manually logged
Whether the participant entered it themselves
n/r
Recording completeness
Share of the session with valid sensor data
n/r
GPS-tracked flag
Whether location data backed the session
n/r
04
Continuous physiological signals
20
Beyond daily summaries, we can pull time-stamped readings throughout the day. Forty-seven distinct signal types are supported in total, though coverage varies enormously by platform. Apple Health Kit reaches into clinical territory that no other consumer wearable does.
Heart rate
Continuous beat-to-beat readings
Heart rate variability
Beat-interval variation, in milliseconds
Respiratory rate
Breaths per minute through the day
Blood oxygen (SpO₂)
Peripheral oxygen saturation
Stress level
Device-computed physiological stress score
Body temperature
Absolute reading and deviation from baseline
VO₂ max
Estimated cardiorespiratory fitness
One-minute heart rate recovery
How fast HR drops after peak exertion
Weight & body composition
Weight, body fat %, BMI, lean mass
Daylight exposure
Time-weighted light exposure; useful for circadian endpoints
Standing time & stand hours
Time upright and hours with movement
Water intake
Logged hydration volume
Sleep breathing disturbance
Breathing irregularity events per hour asleep
Blood pressure
Systolic and diastolic from a paired cuff
Blood glucose
Readings from a paired CGM or meter
ECG voltage & AFib burden
Single-lead ECG trace and rhythm burden
Lung function
FEV1, forced vital capacity, peak flow, inhaler use
Nutrition logging
Carbohydrates and caffeine intake
Mindfulness minutes
Logged meditation and breathing sessions
Safety events
Falls, irregular-rhythm and sleep-apnea alerts
05
Recovery & readiness
10
Day-level composite scores that roll sleep, HRV and resting heart rate into a single number. Useful for tracking day-to-day fluctuation within a participant, but the scores are proprietary and not directly comparable across platforms — a WHOOP recovery of 62 and an Oura readiness of 62 mean different things.
Recovery score (0–100)
Device's overnight recovery composite
Readiness score
Aggregated readiness-to-perform indicator
Body battery
Garmin's daily energy reserve, 0–100
Daytime stress score
Continuous physiological stress estimate
Strain vs recovery balance
Whether the day's load exceeded recovery capacity
Sleep need vs actual
Recommended sleep minus what was achieved
HRV baseline deviation
Today's HRV against a personal rolling baseline
Daily resting heart rate
Lowest resting HR recorded for the day
Recovery time recommendation
Hours advised before the next hard effort
Autonomic balance
Sympathetic vs parasympathetic dominance
06
Women's health & cycle
9
Cycle and reproductive-health tracking. Apple, Fitbit and Garmin offer dedicated cycle logging; Oura infers cycle phase from temperature trends. WHOOP surfaces no cycle data at all, which rules it out for any study with a cycle-related endpoint.
Menstrual cycle logging
Period start, end and flow level
Cycle phase prediction
Current phase of the menstrual cycle
Ovulation prediction
Estimated ovulation date
Fertility window
Days of peak fertility in the cycle
Cycle regularity
Variability in cycle length over time
Basal body temperature
Morning waking temperature
Symptom & mood logging
Cramps, mood and sex-drive entries
Pregnancy tracking
Weeks gestation and milestones
Contraceptive logging
Method and adherence tracking
Coverage
Platform coverage at a glance
Share of the 47 continuous signal types each platform supports. Breadth is not the same as fitness for purpose. Oura supports fewer signal types than Fitbit but delivers the most detailed overnight data of any device on this list.
Apple Health Kit45 / 47
Garmin22 / 47
Fitbit21 / 47
Oura Ring16 / 47
WHOOP9 / 47
Availability also depends on device model and on the permissions each participant grants at enrollment. We confirm both during onboarding and report actual capture rates in every study report.
Design
What this means for your study design
Selecting the device for your endpoints
As every participant in a Reputable study wears the same device, device selection is an endpoint decision, made before enrollment opens and fixed for the duration of the study. We work backward from the claim: list the endpoints the study has to support, identify which platforms deliver all of them, then choose among those on participant burden, cost and expected compliance. A metric that only one platform reports can absolutely carry a primary analysis, provided that platform is the one the study is built on.
HRV is not one measurement
Apple Health Kit reports HRV as SDNN; Garmin, Oura and WHOOP report RMSSD. These are different calculations on the same underlying signal and produce different absolute values. Running one device per study removes this problem inside the study, but it still shapes what the numbers can be compared against. Published reference ranges, competitor benchmarks and results from any prior study only apply if the HRV method matches. We confirm which method the selected device uses and pre-specify it in the protocol.
Wear compliance is measured, not assumed
Missing data in a wearable study is rarely random. We track device non-wear and per-metric capture rates for every participant, pre-specify the minimum wear threshold for a valid day, and report attrition transparently in the study report.
Quality control on incoming data
Consumer wearable feeds contain occasional implausible values: out-of-range heart rates, corrupted duration fields, unit mismatches. Every incoming record passes automated range and consistency checks before it enters a locked analysis dataset, and any field that fails validation is excluded with the exclusion documented in the study report rather than silently repaired.
Next step
Building a study around these metrics?
Tell us the claim you want to support and we will map it back to the endpoints, device and sample size that can actually support it, then design, run and report the study end to end.