# Your Polar Loop, understood. > https://meetkeely.com/polar-loop · Updated 2026-09-28 · Keely, by Metrica Fit LLC **Keely is an iPhone app for the Polar Loop.** It connects to the band directly over Bluetooth and turns its heart rate, beat-to-beat intervals, movement and skin temperature into four numbers: Recovery each morning, Load with a daily target, Stress as it happens, and Sleep against your need. - **Works with:** The Polar Loop, Polar’s screenless band - **Needs:** An iPhone with iOS 26 or later - **Price:** Free, with no subscription - **Connects:** Directly over Bluetooth, instead of Polar Flow - **Your data:** Raw heart data stays on your iPhone - **Availability:** Coming to the App Store ## What Keely adds to your Loop The Loop has no screen. Its lights and its app are its whole voice, and Keely is built to be that voice: four numbers, each explained. - **[Recovery](https://meetkeely.com/recovery), every morning.** Last night’s HRV, resting heart rate, sleep, breathing rate and skin temperature against your own 30-night normal, from 0 to 100 %. Tap it to see what moved it. - **[Load](https://meetkeely.com/load), with a target that moves.** Every minute counted by its heart-rate zone, linear with no ceiling, and a range for the day set by your Recovery and your last four weeks. - **[Stress](https://meetkeely.com/stress), as it happens.** Live from the Loop while Keely is open, from 0 to 100 against your own calm, and only while you’re still. - **[Sleep](https://meetkeely.com/sleep), as a story.** Stages with heart rate, HRV, breathing and stress on one timeline, your need, your consistency and a lights-out time. - **Every morning, kept.** A calendar of each morning’s Recovery at the foot of Today. Every formula is public on the [methodology page](https://meetkeely.com/methodology), so you can check any number. ## What the Loop gives Keely The Loop records around the clock, whether or not your iPhone is nearby, and Keely catches up at the next sync: - heart rate, every 5 minutes at rest and every second during activity; - beat-to-beat intervals, for HRV, breathing rate and stress; - steps and activity, minute by minute; - skin temperature; - sleep stages, from the Loop’s own staging. With Keely open and the band connected, heart rate and beat intervals also stream live. Keely looks after the band, too: it sets the band’s clock, syncs in the background, deletes data from the band only after it’s saved on your iPhone, and installs firmware updates only after a successful sync, because an update erases the band. ## Moving from Polar Flow A Loop works with one app at a time. Keely connects to it directly, so the band moves from Polar Flow to Keely. Your history stays in Polar Flow, and the move takes about two minutes. Keely walks you through it when you pair. 1. **Remove the Loop in Polar Flow.** In the Flow app, remove the band from your devices. 2. **Forget it on your iPhone.** In Settings › Bluetooth, tap the info button next to the Loop, then Forget This Device. 3. **Reset the Loop.** Put it on its charger and press the reset pin on its underside. 4. **Pair it with Keely.** Open Keely, tap Get started, and keep the Loop on its charger next to your iPhone. Read the [full comparison of Keely and Polar Flow](https://meetkeely.com/compare/polar-flow) before you move. ## Your data Keely computes every score on your iPhone. Your raw heart data stays there. Your account backs up only your profile, band details and daily summaries, so a new iPhone can pick up where you left off. There are no ads, and your data is never sold. The [Privacy Policy](https://meetkeely.com/privacy) has the details. ## Frequently asked questions ### Does the Polar Loop work with iPhone? Yes. The Loop pairs with an iPhone over Bluetooth, either through Polar’s own Polar Flow app or through Keely. Keely needs iOS 26 or later. ### Do I need Polar Flow to use Keely? No. Keely connects to the Loop directly and sets it up itself, so you don’t need a Polar account or the Flow app. ### Can I use Polar Flow and Keely at the same time? No. A Loop pairs with one app at a time. You can move back to Polar Flow later: use Forget this Loop in Keely’s band sheet, which resets the band, forget it in your iPhone’s Bluetooth settings, then pair it in Flow. ### Does the Polar Loop need a subscription? No. Polar sells the Loop without one, and Keely is free, with no subscription either. ### Does the Polar Loop measure skin temperature? Yes. The Loop has a skin temperature sensor, which Polar makes available through its software kit rather than in Polar Flow. Keely reads it and uses it in your Recovery, against your normal. ### Does the Polar Loop measure blood oxygen? No. It has an optical heart-rate sensor, an accelerometer and a skin temperature sensor, but no blood oxygen (SpO₂), ECG or GPS. ### Can the Polar Loop wake me with a silent alarm? No. The Loop has no vibration motor, so neither Keely nor Polar Flow can use it as an alarm. ### Does the Polar Loop measure HRV? Yes. The Loop records the intervals between heartbeats with its optical sensor, and Keely computes HRV (RMSSD) from them, including during deep sleep for your Recovery. ### Is Keely made by Polar? No. Keely is an independent app by Metrica Fit LLC. It isn’t affiliated with or endorsed by Polar Electro. It uses Polar’s public software kit for Bluetooth devices to talk to the band. ### Does Keely work with other Polar devices? Not yet. Keely is built and tested for the Polar Loop. ### Where can I buy a Polar Loop? From Polar or a retailer. The Get a Polar Loop button below goes to one. Facts about the Loop come from Polar: [its specifications](https://support.polar.com/e_manuals/polar-loop/polar-loop-user-manual-english/technical-specifications.htm) and [its store page](https://www.polar.com/us-en/loop), checked September 28, 2026. ## Keep reading - [Methodology](https://meetkeely.com/methodology): How Keely computes Recovery, Load, Stress and Sleep from your Polar Loop: every input, weight and constant, published so that each number can be checked. - [Polar Flow](https://meetkeely.com/compare/polar-flow): Two free apps for the same band. How Keely compares with Polar Flow for the Polar Loop: Recovery and Nightly Recharge, Load, stress, sleep, data and switching. - [Recovery](https://meetkeely.com/recovery): Keely’s Recovery is a 0–100 % score each morning: last night’s HRV, resting heart rate, sleep, breathing and skin temperature against your own normal. Keely is coming to the App Store for iPhone (iOS 26 or later). Need a Polar Loop? https://meetkeely.com/loop (an affiliate link: as an Amazon Associate, Metrica Fit earns from qualifying purchases).