Health App Data

Feelmo fully discloses what data it exchanges with Apple's Health app (HealthKit). What we read, what we write, and what we don't touch — we believe trust begins right here.

Feelmo isn't an app that tries to guess your emotions. It's a daily companion that gently watches over the balance of your autonomic nervous system. That's exactly why we want to be as transparent as we can about how we handle the data that becomes the material for that watching-over. By the time you've read this page, you should have a clear picture of what data Feelmo needs, why it needs it, and how it keeps its hands off the things it doesn't.

What is HealthKit

HealthKit is the mechanism that gathers and stores the health data measured by your Apple Watch and iPhone all in one place, inside iOS's Health app. Heart rate variability, heart rate, sleep, step count, and more all collect first into HealthKit.

Rather than running its own sensors, Feelmo takes the approach of reading and using the data already in HealthKit, only within the limits you permit. In other words, the data belongs to you and you alone, and Feelmo's role is to "borrow it and translate it into watching-over." Read permissions are split by data type, and you can revoke them at any time later.

Data Feelmo Reads

During onboarding, Feelmo explains and requests the basic HealthKit items needed to calculate your Balance. If you later turn on an optional feature, it may ask separately for the additional item that feature needs, after explaining why. You choose permissions by data type and can revoke them anytime.

Data	What it's for
Heart rate variability (HRV / HRV-derived clue)	The central metric behind your sense of balance (Balance score)
Heart rate & heart-rate recovery	Background information such as resting heart rate, for the Vital Signs card on the Wellbeing tab. Heart-rate recovery (Apple Watch, one minute after a workout) is used as a hint about a delay in recovery (where supported, optional)
Sleep	To read your balance from data taken while you sleep with little body movement, and to watch over your sleep
Wrist temperature, respiratory rate, blood oxygen (SpO₂) (where supported)	For the Vital Signs card that shows your daily signs (not a diagnosis)
Steps & exercise	To watch over the relationship between your behavior and balance (habit & activity log)
Ambient light & daylight (where supported)	To watch over the relationship between sunlight and balance (habit & activity log)
Mindfulness minutes	To bring mindfulness (meditation / breathing) minutes already recorded in Health into the watching-over (also written)
Water & caffeine (Nutrition) (where supported)	So water and caffeine you logged in other apps (e.g. WaterMinder) or by hand in Health are also summed into your Wellbeing "water / caffeine" — read because your own entries alone can't total other sources (also written)

HRV is at the center

The most important item in this list is heart rate variability (HRV). HRV is a metric that expresses how naturally the intervals between each heartbeat (the R-R intervals) fluctuate. The richer the fluctuation, the more it's taken as a sign that your autonomic nervous system is working flexibly, adapting to the situation.

Feelmo translates this heart rate variability into the balance gauge on Home and into the expressions of your 6 companions. Because Apple Watch mainly records heart rate variability in the form of HRV-derived clue, that's where Feelmo begins too.

Your Balance score is not a score for comparing yourself with others. Low means "fluctuating," high means "settled" — read it as the difference from your own baseline. After several days to weeks of records, that baseline can draw on more of your own history, but this does not guarantee the accuracy of any score or forecast. For more on how baselines work, see Baseline too.

The wrist is weak to movement

Apple Watch measures heart rate variability using a method that captures blood flow with light (PPG), so the values tend to get noisy while you're walking or exercising. That's why Feelmo focuses on reading data from while you sleep with little body movement and measurements taken while you sit calmly. There's no need to worry if daytime values occasionally drop out or wobble — Feelmo is built to quietly pick up the signs from your calmer moments instead.

Data Feelmo Writes

Feelmo writes just two kinds of thing back to HealthKit — each optional, and only where it's relevant.

Data	What it's for
Mindfulness minutes	Breathing sessions you complete are added as Mindful Minutes in the Health app
Water / Caffeine (Nutrition)	Water and caffeine you log by hand in Feelmo are saved as dietaryWater / dietaryCaffeine

• State of Mind is never written by Feelmo. When you turn mood sync on (opt-in, iOS 18 and later, off by default), it is one-way: the app imports (reads) the entries already in Health's State of Mind into your Mood Log
• Your Balance score itself is never written back to the Health app — it's a value meant only for watching over within Feelmo
• A write permission is requested when you first use the corresponding optional feature, after the app explains what will be written and why

When you want to bring the moods you've already recorded in iOS's built-in "State of Mind" into Feelmo's Mood Log, turn that sync on. Even left off, recording and reflecting on your moods within Feelmo works just the same.

What Feelmo Does NOT Do

• We do not use data obtained from HealthKit for advertising or marketing
• We do not provide or sell HealthKit data to third parties, including data brokers (we comply with Apple's guidelines)
• We do not perform medical diagnosis or individual profiling with the data we obtain
• We do not upload HealthKit-derived data or scores to the cloud on our own (as a rule, it stays on your device)

Checking & Changing Permissions

You can check and change HealthKit permissions anytime from iOS Settings.

Settings → Privacy & Security → Health → Feelmo

Here you can toggle reading on / off per data type, such as heart rate variability and sleep. There's no need to grant permission for features you don't use.

If you revoke a permission, or have items you haven't granted yet, Feelmo won't suddenly stop. Only the features that use that item become quietly more modest, while the rest keep working as usual. For example, even if you don't grant the daylight data, your Balance score, breathing exercises, and mood logging stay just as they were.

Where the Data Lives

The Balance score, emotion logs, and activity logs calculated from the data read out of HealthKit are stored only on your device and not saved to iCloud (following Apple's guidelines, we do not save HealthKit-derived health information to iCloud). We also don't automatically send it to our servers. The only things synced via iCloud are "settings" such as notifications and display.

This is to uphold Feelmo's core stance — "your body's data stays inside your device" — at the integration level too. You can delete your records at any time. For details, see Data & Privacy and Apple Watch and HealthKit.