01
All day and all night.
inner tape records in the background, even with your iPhone locked, all day and night with Pro. If recording stops, it can notify you.
Sun 1 Nov
23h 12m recorded
Heart recorder for iPhone
Your heart, recorded.
Heart rate, HRV and ECG from your chest strap, day and night. Stored on your iPhone. Exported as files whenever you want.
Coming soon to the App StoreSee how it works
Works with Polar H10. Requires an iPhone with iOS 17 or later. US$6.99 a year.
LiveUpdates every 5 s
Recordingfor 4h 41m82%
On this iPhone · 53,952 beats today
Pause
Today
12:47-14:47
Heart rate
71bpmNow
HRV
Heart rate variability
34.7msNow
ECG
Heart's electrical signal
LiveNow
14:47:0714:47:0914:47:1114:47:1314:47:15
10 seconds shownOpen ECG ›
LiveDaysSettings
What is inner tape?
inner tape is an iPhone app that records the time between heartbeats from a Polar H10 chest strap, all day and night, and keeps the recordings on your iPhone as files you can export. It also records ECG and chest movement.
It is made for people who want their own raw heart data: athletes who train by HRV, self-trackers and researchers. It shows what the strap recorded, with no scores and no advice. It is not a medical device.
What it does.
02
Beat by beat, not a summary.
The strap sends the time between beats, and inner tape stores them as they arrive. With a Polar H10 it also records ECG and chest movement.
03
See it live.
Heart rate, HRV, SDNN and pNN50 update every 5 seconds. Look back over 30 minutes, 2 hours or the whole day.
LiveUpdates every 5 s
Recordingfor 4h 41m82%
On this iPhone · 53,952 beats today
Pause
Today
09:11-11:11
Heart rate
71bpmNow
HRV
Heart rate variability
34.7msNow
ECG
Heart's electrical signal
LiveNow
11:11:0711:11:0911:11:1111:11:1311:11:15
10 seconds shownOpen ECG ›
LiveDaysSettings
04
Your recordings, as files.
Recordings are saved on your iPhone, and backup to your own iCloud is optional. No inner tape account. With Pro, export any day as CSV files for Excel, Numbers, Python or R.
inner-tape_2026-11-01.zip
- heartbeats.csvRR per beat1.4 MB
- ecg.csvECG, 130 Hz95 MB
- movement.csvAccelerometer320 MB
- heart-rate-hrv.csvHR, HRV, SDNN, pNN500.5 MB
Recorded when you choose.
Oura and WHOOP report HRV mostly as a sleep average, and Apple Watch takes short readings. inner tape records the time between beats from your chest strap while it is connected and keeps it on your iPhone.
| inner tape | Polar Flow / Beat | Oura, WHOOP, Apple Watch | |
|---|---|---|---|
| Beat-to-beat (RR) data | When you choose | Not exported | Apple Watch: ~1 min |
| ECG | With Polar H10 | No | 30-s check, some models |
| Sensor | Chest strap | Chest strap | Light on the skin |
| No sign-up needed | Yes | Flow: required | Oura, WHOOP: required |
| Data on your iPhone | Yes | Polar cloud | Cloud, except Apple |
| CSV export | Any day or range, with Pro | Web, no RR | Summaries; Apple: XML |
Based on each company's public documentation, November 2026. Apps change, so check before you choose.
Built on the raw signal.
What the strap sends, stored as it arrives.
1/1024s
Time between beats
130Hz
ECG, with Polar H10
200Hz
Movement, with Polar H10
24h
A day, in the background
| Works with | Polar H10 |
|---|---|
| Requires | iPhone with iOS 17 or later |
| Stores | On your iPhone; export as CSV |
One plan.
inner tape Pro
US$6.99a year
All-day and all-night recording, and CSV export. Without Pro, you can record 1 hour a day. Renews every year. Cancel any time. Your recordings stay yours: you can always open them, even if you stop paying.
Coming soon to the App StorePrices in other countries are shown in the App Store.
Common questions.
What does inner tape record?
Heartbeats as RR intervals (the time between beats), from a Polar H10 chest strap, day and night. It also records the heart's electrical signal (ECG) and chest movement.
Where is my data stored?
On your iPhone, as files. If you turn on backup, copies also go to your own iCloud account. There is no inner tape account. Exports are separate: you choose where to save them, such as On My iPhone or iCloud Drive, or share them to another app.
Does inner tape need an account or internet?
No inner tape account. Recording runs over Bluetooth between the strap and your iPhone. The App Store needs a connection for the purchase.
Which chest straps work with inner tape?
Polar H10, the sensor that clips onto the strap. It records heartbeats, ECG and movement. We haven't tested other straps yet. Want yours supported? Tell us through the form below.
Does it record all night?
Yes, with inner tape Pro. It records in the background with your iPhone locked while you wear the strap. Keep Bluetooth on and your iPhone nearby. A lost connection may leave gaps in your recording. Without Pro, you can record 1 hour a day.
Can there be gaps in a recording?
Yes. If the strap loses skin contact, its battery runs out or the Bluetooth connection drops, those minutes are not recorded. Gaps show as "Not recorded" in your charts, and inner tape can notify you when recording stops, if you allow notifications.
Can I export my heart data as CSV?
Yes, with inner tape Pro. Export any day or range as a ZIP of CSV files (heartbeats, ECG, movement, heart rate and HRV) and share it to Files, a Mac, Mail or any app.
What is HRV (RMSSD)?
RMSSD measures how much the time between neighbouring beats changes, in milliseconds. inner tape shows the number, not a score.
Does inner tape sync with Apple Health?
Not in the current version. If you need it, tell us through the form below or in the app. We read every message.
Is inner tape a medical device?
No. inner tape is made for personal fitness and wellness. It is not intended to diagnose, screen for, treat or monitor any disease or condition, and it does not check for heart rhythm problems.
How much does inner tape cost?
inner tape Pro is US$6.99 a year and includes all-day recording and export. It renews every year, and you can cancel any time. Your recordings stay on your iPhone, and you can always open them. Prices in other countries are shown in the App Store.
Tell us what you need.
Questions, feedback, a strap you want supported. We read every message.
Your first night, recorded.
Put on the strap, connect it in inner tape and lock your iPhone. Recording continues in the background. All night with Pro.
Coming soon to the App Store