# Keely: Recovery, Load, Stress and Sleep for your Polar Loop

> https://meetkeely.com/ · Updated 2026-10-11 · Keely, by Metrica Fit LLC

**Keely is a free iPhone app for the Polar Loop.** It reads your Loop and tells you how recovered you are, how hard to go, and how you’re handling the day. Every number is explained, and nothing is made up.

## What Keely measures

- **Recovery, every morning.** When you wake, Keely scores last night against your own 30-night normal, from 0 to 100 %. HRV and resting heart rate carry most of the weight, with sleep, breathing rate and skin temperature alongside. Tap the score to see what moved it: helping, holding back or normal. [How Recovery works](https://meetkeely.com/recovery)
- **Load, with a target that moves.** Load counts every minute by its heart-rate zone. It’s linear and has no ceiling: twice the work is twice the Load. Each morning brings a target range set by your Recovery and your last four weeks, and Balance shows how this week compares with the weeks before. [How Load works](https://meetkeely.com/load)
- **Stress, as it happens.** With your Loop connected and Keely open, stress updates live from your heart rate and beat-to-beat variability, scored from 0 to 100 against your own calm. While you move, it reads your heart rate alone, on the same scale, so the day has one line. [How Stress works](https://meetkeely.com/stress)
- **Your night, as a story.** Sleep stages with stress, heart rate, HRV and breathing on one timeline. See time asleep against your need, how regular your days are, and when to turn the lights out tonight. [How Sleep works](https://meetkeely.com/sleep)
- **Fitness, from real effort.** Keely estimates your VO₂ max from the Loop’s heart rate against the pace of the walks and runs your watch or apps save to Apple Health, on steady, level stretches, with a likely range and your band for your age and sex. [How Fitness works](https://meetkeely.com/fitness)
- **Keely Age.** Your fitness in years: the age whose average mortality risk matches fitness like yours, worked out each Monday from your VO₂ max and nothing else. [How Keely Age works](https://meetkeely.com/keely-age)
- **The journal.** Tag what happened, in a tap or your own words, and see how each thing moves your next morning’s HRV and resting heart rate, against your own normal. [The journal](https://meetkeely.com/journal)
- **Every morning, kept.** A calendar at the foot of Today shows each morning’s Recovery as a ring. Tap any day to see its numbers, or any number for its week, month, six months or year.
- **It learns you.** Your sleep need, your calm, the workouts you name and when you get up adapt to your own days, quietly and within bounds.

## Calm by design

- Missing data is shown as missing, and older readings show their time.
- Every score keeps its inputs, so you can always see why. Every formula is public: [the methodology](https://meetkeely.com/methodology).
- Cool colors mean normal. Warm colors ask for attention.

## Private by default

Your raw heart data stays on your iPhone. Keely backs up only your account, profile, band and daily summaries, so a new iPhone can pick up where you left off. No ads, and your data is never sold. Anonymous usage statistics never include health data, and you can turn them off in Settings. [Privacy Policy](https://meetkeely.com/privacy)

## What you need

- **A Polar Loop.** Keely connects to it directly over Bluetooth, so the band works with Keely instead of the Polar Flow app. Already on Flow? Keely walks you through the move. [The Polar Loop app](https://meetkeely.com/polar-loop)
- **An iPhone** with iOS 26 or later.

Keely learns your normal over your first nights, and the scores firm up as it does.

Keely is an independent app by Metrica Fit LLC. It is not affiliated with or endorsed by Polar Electro. Keely is not a medical device and is not intended to diagnose, treat or prevent any condition.