01 · FEEL
Feel first.
Sit still. Notice your chest — no fingers on your pulse.
The moment
You think you know. Then the truth lands.
Everyone carries a guess about their own heart. Heartio makes you commit to it — then your Watch tells the truth, and the gap teaches you.
You guessed
72
Your heart said
91
19 off — the invisible gap, made visible
How it works
Feel. Lock it in. The reveal.
One guess is thirty seconds. The practice is doing it again tomorrow.
02 · LOCK
Then guess.
Dial the number that feels true. Commit.
03 · REVEAL
The truth lands.
Your Watch tells the truth. The gap teaches you.
Attune
Your heart-sense, scored.
Attune is a living 0–100 score of how well you know your own heart. It climbs as you learn — and the needle only moves when you show up.
0
IN TUNE
Every guess feeds it — and the tougher the moment, the more a good one counts. A perfect guess after an hour-long workout moves Attune more than a perfect live guess does. That’s what keeps 100 an honest brag.
It measures awareness, not health. It is not a medical score.
Guided sessions
Train it in two quiet minutes.
Guided sessions on your wrist. Just you and the beat: settle your breathing, count your heartbeats — don’t touch your pulse — and see how close you were.
Some heart-rhythm conditions can make beats harder to feel. Attunement is a personal training measure, not a medical assessment.
Heartio Plus
Free to play. Plus goes deeper.
The daily game is free, forever. Plus opens the whole picture.
BEST VALUE
Annual
$24.99/yr
just $2.08/mo
7 days free, cancel anytime
Monthly
$3.99/mo
flexible
7 days free, cancel anytime
- Your Attune score & full history
- Guided Attune sessions on your Watch
- Deep insights — where your heart-sense is sharpest
- Unlimited streak history
- Retro theme + your monthly Heart Report
Free keeps the last 30 days of your history. No wall, no guilt — the daily game never locks.
FAQ
Honest answers.
Do I need an Apple Watch?
For live guesses, yes — the Watch on your wrist is the referee, and it’s the only one we trust. No Watch? You can still play sleep and workout guesses from Apple Health data. Live guessing waits until you pair one.
Is Heartio a medical device?
No. Heartio is an awareness practice — a game about noticing, not a health product. It measures awareness, not health. It is not a medical score, and nothing in Heartio is medical advice.
What’s the Attune score?
A living 0–100 read of how well you know your own heart, built from how close your guesses land over time. It climbs as you learn and drifts when you stop showing up. Tougher guesses count for more: a perfect guess after an hour-long workout moves it more than a perfect live guess does. That’s what keeps 100 an honest brag.
What’s free, and what’s Plus?
Free is the real game: your Daily Heartio, live guesses, streaks, and your last 30 days of history. Heartio Plus adds your Attune score & full history, guided Attune sessions on your Watch, deep insights, unlimited streak history, and the Retro theme plus your monthly Heart Report. $24.99/yr (just $2.08/mo) or $3.99/mo, 7 days free, cancel anytime.
How do Lifelines work?
Every 7 days of playing banks a Lifeline. Miss a day, and a Lifeline catches you — the streak never blinks. A missed day is a Lifeline story or a fresh start, never a failure.
I have Afib or another arrhythmia — does Heartio work for me?
Heartio was built by someone with Afib — that’s the whole origin story. Two honest notes: during an active episode an irregular rhythm doesn’t have one clean number and wrist sensors are less reliable, so Heartio isn’t a tool for those moments. And nothing here replaces your cardiologist’s guidance — Heartio measures awareness, not health, and is not a medical device. For the moments in between, it’s a way to rebuild a calmer, more curious relationship with a number you’re already paying attention to.
One more honest note: AFib varies a lot person to person. If you’re in AFib most or all of the time, the live-guessing part may not work well for you — an irregular rhythm doesn’t resolve to a single number. Workout and sleep predictions may still be interesting, but we’d rather you know before you download.
Where does my data live — and can I delete my account?
Heart-rate readings come from Apple Health, with your permission. Your guesses, scores, and streaks live in your Heartio account, and you can delete that account — and everything in it — right from the app. Here’s exactly how.
Can I use Heartio on iPhone alone?
Yes — sleep and workout guesses work from Apple Health data on iPhone. The live guess, the one where you feel your chest and commit to a number, needs an Apple Watch. That’s the part worth pairing for.