The smartest runners track their resting heart rate and HRV daily — not just their pace. Pulse Rate gives you those metrics using only your iPhone camera.
Running is the sport where heart-rate data is most likely to mislead you, and knowing how is more useful than any app feature. Optical wrist sensors can lock onto your arm swing instead of your pulse when step rate and heart rate converge — a runner at 170 steps per minute with a true heart rate near 170 bpm is the textbook case, and the giveaway is a trace that looks unnaturally flat. Heart rate also lags effort by tens of seconds, so a short rep finishes before the number reflects it, which makes heart rate a poor pacing tool for intervals and an excellent recovery tool immediately afterwards. Both problems disappear when you stop moving. That is why Pulse Rate is built around readings taken while you are still: the morning resting measurement, and the one-minute recovery reading after a hard session.
One 60-second reading. Pulse Rate compares it to your own baseline and gives you a plain answer: run hard, run easy, or make it a rest day.
Readings write into Apple Health, so your morning numbers sit alongside the runs your other apps already log there.
Before you act on a heart-rate number from a run, it helps to know the three ways running specifically corrupts it. None of these apply to a still, seated reading — which is the argument for taking one.
Optical wrist sensors can latch onto the rhythm of your arm swing when your step rate happens to sit near your heart rate — a runner at 170 steps per minute with a true heart rate near 170 bpm is the classic case. The trace looks suspiciously flat and suspiciously round. A resting fingertip reading has no cadence to lock onto, which is why it is the more trustworthy daily number.
Heart rate takes tens of seconds to catch up with a change in effort, so a short rep can be finished before the number reflects it. That is why heart rate is a poor pacing tool for anything under a few minutes and an excellent recovery tool afterwards, once the effort has stopped and the signal has settled.
A chest strap reads the heart’s electrical signal directly; a wrist or fingertip sensor infers pulses from light absorption. Under movement the electrical measurement holds and the optical one degrades. At rest the gap narrows sharply — which is exactly why Pulse Rate is built around the stationary reading rather than the mid-run one.
Cold constricts the capillaries in your fingertips, which is where a camera reading gets its signal. After a January long run your hands may need a couple of minutes indoors before the trace is clean. If a reading looks noisy or refuses to settle, warm the hand and take it again rather than logging the bad one.
Heart-rate recovery — how far your pulse falls in the minute after you stop — is one of the few running numbers a phone camera measures better than a watch, because you are standing still for it by definition. Run it the same way every time and it becomes a fitness trend.
| When | What you do | Why it matters |
|---|---|---|
| Last rep | Finish the final hard interval and stop cleanly. | A gradual jog-down blurs the start point and flattens the drop you are trying to measure. |
| 0:00 | Note the peak effort you just finished. | Recovery is only comparable between sessions that ended at a similar intensity. |
| 0:15 | Stand still and start a camera reading. | Fifteen seconds lets your hand steady and the initial signal settle without missing the fall. |
| 1:00 | Record the reading as your one-minute recovery figure. | One minute after peak effort is the conventional window, so your own numbers stay comparable week to week. |
| Next morning | Take the usual resting reading before getting up. | A resting heart rate several beats above your normal baseline the morning after a hard session is the clearest early sign the work has not been absorbed yet. |
Pulse Rate is a wellness app, not a medical device, and none of the readings above diagnose anything. Camera measurement needs you to be still, so every step in this routine is placed at a moment when you already are.
The morning recovery signal the wearables sell you — HRV read against your own baseline — is a sixty-second reading you can take before you have found your shoes.
Cadence lock is when an optical heart-rate sensor latches onto the rhythm of your arm swing rather than your pulse, which happens most often when your step rate sits close to your true heart rate — around 170 steps per minute against 170 bpm, for example. The tell is a trace that is suspiciously flat and suspiciously round for the effort you were making. A stationary fingertip reading has no cadence to lock onto.
Because it arrives late. Heart rate takes tens of seconds to respond to a change in effort and keeps climbing after you ease off, so a 400 m rep can be over before the number reflects what you did. Use perceived effort or pace during short reps, and use heart rate afterwards — the recovery phase is where the signal is both settled and informative.
Finish the last hard rep and stop cleanly rather than jogging down, since a gradual wind-down blurs the starting point. Stand still and begin a camera reading at about fifteen seconds, which lets your hand steady without missing the fall. Record the value at one minute after peak effort. Keep the ending intensity roughly similar between sessions, or the numbers are not comparable.
Under load, yes, and clearly so. A chest strap reads the heart's electrical signal and holds it through hard running, while any optical sensor — wrist or fingertip — degrades with movement. At rest the gap narrows sharply. That is the whole reason Pulse Rate places every reading at a moment when you are stationary rather than trying to compete mid-run.
Cold constricts the capillaries in your fingertips, which is exactly where a camera reading gets its signal. After a January long run your hands may need a couple of minutes indoors before the trace settles. If a reading refuses to stabilise, warm the hand and take it again rather than logging a bad measurement — one corrupted value distorts a short trend more than a missing one does.
A resting heart rate several beats above your own normal baseline the next morning, or a morning HRV clearly below your recent range, are the earliest signals worth acting on. Neither is meaningful in isolation — you need two to three weeks of consistent readings before you know what your normal is. Once you do, the morning after a hard session becomes the most informative measurement of the week.
Pulse is free. Forever. No wearable, no card, no catch.