Plenty of numbers, no sense of normal
An Apple Watch records a great deal overnight and through the day: heart rate variability, resting heart rate, sleep stages, VO2 max, steps and more. All of it lands in Apple Health, which doesn’t answer the question most owners have when they look at a morning reading: is this normal for me?
A resting heart rate of 58 bpm sits comfortably inside the textbook adult range. For one runner, it is a typical morning. For another, it is six beats above where they have been all month, after a late night and the first signs of a cold. A population range can’t tell those two mornings apart, but a personal baseline can.
Dedicated recovery bands answer that question with new hardware and a subscription, and several Apple Watch apps, such as Cinder and Horef Rings, answer it in their own ways. InnerRipple is free, needs no account, and does all of its work on the iPhone and Apple Watch.
Why InnerRipple was built
InnerRipple comes from Still Raft, a small independent iOS studio run by one developer. For about six months, the developer built two apps alongside other work, putting in thirteen to fifteen hours a day on five or six hours of sleep, and stopped listening to what their body was signalling. One night made that impossible to ignore.
Looking at longevity wearables beyond the Apple Watch, the developer concluded that most brands read similar signals from similar sensors, and what sets them apart is how the data is interpreted. The Apple Watch already records heart rate, HRV, sleep and exercise, and a smart scale, a blood pressure cuff or a pulse oximeter could add to Apple Health. What was missing was an app that compares the wearer with their own past, shows the research behind its thresholds and suggests one small action for the day. InnerRipple has been on the App Store since June 2026, and Still Raft offers it for free.
How InnerRipple works
TL;DR: InnerRipple reads Apple Health on the device and compares each morning’s overnight HRV, resting heart rate and breathing rate with the wearer’s own last 29 nights. Three figures lead the Today screen: Recovery, Today’s Investment and Net today. Reference ranges link to the study or guideline behind them, and apart from bloodwork entries, which sync through the wearer’s own iCloud, nothing leaves the phone and watch unless the wearer shares it.
A reading within half a standard deviation of the wearer’s usual scores a neutral 50 for that signal, and only a bigger move counts up or down. Because each reading is measured against the wearer’s own spread, a swing that is routine for one person counts for less than the same swing for someone whose readings are usually steady. Resting heart rate counts twice as much as HRV, because the developer found overnight HRV carried very little from one night to the next across 174 nights on an Apple Watch Series 5. Blood oxygen, wrist temperature and sleep duration are compared with fixed reference ranges instead, such as 7 to 9 hours of sleep for adults from the National Sleep Foundation.
On first launch, InnerRipple reads up to 180 days of Apple Health history, so wearers with past Apple Watch data get personal comparisons on the first morning. For a new wearer, each reading joins the comparison once it has five nights of values; until then, Recovery uses fixed reference ranges.
| Figure | What feeds it | What it tells the wearer |
|---|---|---|
| Recovery | Overnight HRV, resting heart rate and breathing rate against the last 29 nights; wrist temperature, blood oxygen and sleep duration against fixed ranges | How the body looks this morning against its own recent normal, as a percentage. A usual morning sits a little above 50% after a full night’s sleep. |
| Sleep | Up to eight rows: duration, regularity, efficiency, chronotype, deep sleep, awakenings, overnight heart rate dip and breathing disturbances | Whether last night was enough, and how it compares with the wearer’s usual nights. Shown as rows, not a single score. |
| Today’s Investment | Steps, exercise minutes, stand hours, mindful minutes, active energy and time in daylight, against daily targets | What the wearer has done for their health today, from 0 to 100, climbing as the day goes on. |
| Net today | HRV and resting heart rate against baseline, plus sleep, movement, exercise, VO2 max, mindful minutes and daylight | The day’s balance across those contributors, in minutes or days. The app calls it a storytelling unit, not a forecast. |
Around those figures, InnerRipple adds:
- Daily action: one suggestion, such as an earlier night, a lighter day after raised resting heart rates, or a step target. The next morning, InnerRipple checks Apple Health to see whether it happened, so tapping Plan never counts as done on its own.
- Signal Status: every reading the app uses, marked against the baseline or a published range, with a trend arrow and a Source link.
- Fitness Age: an estimate from VO2 max, or from resting heart rate and weekly exercise where there is no VO2 max reading, with the arithmetic shown.
- Trends and Insights: the daily balance over 7 to 180 days, and patterns from the wearer’s own data, written on the device by Apple Intelligence where it is available.
- Bloodwork: lab results scanned or typed in and tracked over time, synced only through the wearer’s private iCloud.
Worked example: a late night and a cold
This week is illustrative rather than from a real wearer, with each morning’s Recovery calculated using the app’s own formula. The runner wears an Apple Watch Series 5, which records neither blood oxygen nor wrist temperature. Over the last 29 nights, their overnight HRV has averaged 48 ms, typically within about 10 ms, and resting heart rate has averaged 53 bpm, typically within about 2 bpm, on about 7 hours 20 minutes of sleep.
| Day | What happened | HRV (ms) | Resting HR (bpm) | Sleep | Recovery |
|---|---|---|---|---|---|
| Mon | Normal day, easy 5K | 49 | 53 | 7h 25m | 56% |
| Tue | Late work event | 46 | 54 | 7h 10m | 56% |
| Wed | Short night, sore throat | 34 | 59 | 5h 05m | 15% |
| Thu | Cold, no run | 31 | 61 | 6h 40m | 19% |
| Fri | Cold easing, rest | 38 | 58 | 8h 15m | 34% |
| Sat | Short walk | 44 | 55 | 7h 50m | 56% |
| Sun | Easy 5K | 48 | 53 | 7h 30m | 56% |
Wednesday shows the clearest change, with Recovery falling from 56% to 15%. Resting heart rate rose six beats, three times its usual spread, which takes the heaviest-weighted reading to the bottom of its scale. HRV fell about 30% below baseline, and a five-hour night pulled the score down further. To most people, 34 ms and 59 bpm wouldn’t look unusual, but against this runner’s own last 29 nights, they stand out.
Sleep bounced back first. Friday’s 8 hours 15 minutes was the longest night of the week, yet Recovery read 34% because resting heart rate was still five beats up and HRV was still low. By Saturday, it was back to 56%, three days after the dip, a gap between “slept well” and “recovered” that a sleep score alone would hide. InnerRipple never diagnoses an illness: on a morning like Wednesday it suggests a lighter day, and after several raised mornings in a row it says so.
Quick answers
How is InnerRipple different from Apple's own Vitals and Readiness?
Apple’s Vitals app flags overnight readings outside a wearer’s typical range, and on Series 12 and Ultra 4 Apple adds a daily readiness score. InnerRipple works back to Series 4 on watchOS 10, shows the readings behind each morning’s Recovery, links its ranges to their sources, and checks whether the day’s suggested action happened. It is free and does its work on the device.
How many days does InnerRipple need before the scores mean anything?
A wearer with past Apple Watch data gets personal comparisons from the first morning, because InnerRipple reads up to 180 days of existing Apple Health history. For a new wearer, each reading joins the comparison after five nights, and the app’s written insights wait for 14 days of data.
Does any of my health data leave my phone?
Only bloodwork entries, which sync through the wearer’s own private iCloud, and anything the wearer chooses to share. InnerRipple has no servers, no account and no analytics, and Insights written by Apple Intelligence use Apple’s on-device model.
On the wrist and on the phone
- Requirements: iOS 17 or later on iPhone XS or newer, iPadOS 17 or later, and watchOS 10 or later, which covers Apple Watch Series 4 and later, every SE and every Ultra. Older watches omit blood oxygen (Series 6 and later) and wrist temperature (Series 8 and later, Ultra and SE 3).
- Apple Watch app: four pages, covering Today, the day’s balance, a sleep recap after waking, and Mindfulness, which includes 5 or 10 minutes of resonance breathing with live heart rate.
- Complications and widgets: three watch widgets for complications and the Smart Stack, and three iPhone widgets for the Home Screen and Lock Screen. On a locked iPhone, widgets show the scores but hide the readings.
- Notifications: a morning summary at 8 a.m. by default, a reminder for the day’s action, and optional wind-down and sunset reminders.
- Data export: a full backup and spreadsheet (CSV) files, with a restore that adds back anything missing.
Privacy, price and limits
InnerRipple has no servers, analytics, accounts, or third-party SDKs, and all scoring happens on the iPhone and Apple Watch. Location is optional and is used only to work out local sunset times, rounded to about a kilometre and kept on the device. The app is free, with no ads, no subscription and no in-app purchases.
InnerRipple is an educational tool, not a medical device, and it doesn’t diagnose or treat any condition. It also can’t score what it can’t measure, such as alcohol, diet quality, medication or existing conditions, so its scores are one input among many.
More information: InnerRipple on the App Store.
Author: the developer of InnerRipple at Still Raft, edited by the5krunner.
If you enjoyed reading this, here is another in the Indie Spotlight series: Indie App Spotlight: Runbo turns Apple Watch data into today’s run.
Last Updated on 12 November 2026 by tfk the5krunner
Small things I always use
- Garmin 90-degree charging adapter: Charges your Garmin with any USB-C cable. Essential when travelling. I use one.
- Body Glide: The blue anti-chafing stick swimmers and runners carry. I use it.
- Speedo earplugs: Fewer ear infections and no cold-water dizziness. I use them.
- Dryrobe Advance: My winter changing robe for open-water swims. I use one. A cheaper option is the AONYIYI changing robe.
- Maurten: Race fuel that stays easy on the stomach. I use them.
- Beet It Sport nitrate shots: Beetroot shots I take in the days before a race. I use them.
- Garmin charging puck: The quickest way to top up before a session. I use one.
- Injinji: Toe socks that stop rubbing, so you run more. I use them.
- Ultimate toe protectors: Stop black toenails on long runs. They work. I use them.
- Compressport R2 v2 calf sleeves: My calf sleeves of choice. I use them.
- Cellucor C4: My pre-workout before hard sessions.
- TPU tubes: Schwalbe Aerothan, Tubolito and Pirelli SmarTube. Light, tiny spares. I use all three.
- G8 insoles: Adjustable arches, perfect position. I use them.
- Cycplus Cube: A 97g electric pump that gets a road tyre rideable in two minutes. I carry one. 5% off with code THE5KRUNNER.
Health, recovery and sleep
- Kineon MOVE+: Red and infrared light for sore knees, Achilles and other joints after hard training. I use it.
- FreeStyle Libre 3 Plus: Shows how my blood sugar responds to diet. Occasional use.
- hDrop: Measures my sweat loss in summer and indoors. I use it.
- Fourth Frontier Zone: Checks my heart under load in hard sessions.
- Oura Ring 5: My partner’s recovery tracker of choice.
- Eight Sleep: A cooling mattress cover my partner and I use nightly.
Watches and sensors
- Polar H10: My daily driver for waking HRV.
- Polar Verity Sense: My backup arm-worn HR sensor.
- Nomad bedside charger: Charges my iPhone and Apple Watch overnight. I use it, and many of their bands.
- Train.Red: The best muscle oxygen sensor I’ve used. Occasional use.
- Tymewear: Accurate heart rate and reliable ventilatory zones. I use it to pace endurance rides over an hour.
- Garmin Forerunner 970: A pro-grade triathlon watch. I use this.
- Apple Watch Ultra 4: My daily smartwatch. No phone needed on rides.
On the bike
- Continental GP5000 for everyday riding, and Aero 111 on the front for special occasions. I use both.
- Helmets: Specialized S-Works Evade 3 for road riding, and Rudy Project Wing for TT-style races. I use both.
- Ravemen FR300: A front light that mounts under your Garmin or Wahoo. I use one.
- Ravemen FR1000: The light and the computer mount in one unit, so nothing else goes on the bars. Better than mine.
- Ravemen FR1500SE: 1,500 lumens hanging under your Garmin, for proper night rides.
- Ravemen FR1100SE: 1,100 lumens under your Garmin, and up to 46 hours on slow flash.
- Ravemen FR500: A brighter FR300 with the same mount.
- Wahoo TRACKR Radar: I use it on one bike and Varia on the other. They perform the same.
- Garmin Varia RTL515: Radar that warns you of cars from behind. I use this model.
- Wahoo ELEMNT Roam 3: The bike computer that’s easy to use. I use mine on most rides.
- Favero Assioma Pro RS2: Accurate power pedals that swap easily between bikes. I use this model.
Home and indoor training
- NPE Runn: Makes my basic treadmill smart, sending more accurate speed and distance to my watch and Zwift. I use it.
- Google Wifi: Keeps Zwift connected in my pain cave. I use it.
- Apple TV 4K: Zwift on the big screen. I use two.
- Google Nest Doorbell (wired, 2nd gen): My video doorbell, running in both Google Home and Apple Home via Starling. I use it.
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. See the gear tfk uses. ID
