Get ahead of your migraine.

Know your Limits combines your sleep, your HRV and air pressure to flag your high-risk days, and learns which triggers are yours.

I want to try it See what it measures

A woman in sportswear holds her head in pain — Migraine risk **High**

Short night
5 h 10

HRV below baseline
38 ms

Air pressure
−6 hPa

1.2 billionpeople live with migraine.1

2nd causeof disability worldwide, and the 1st in women under 50.2

80 %of patients name stress as a trigger; 53 % weather and 50 % poor sleep.3

And every morning, how much you can give.

The app reads what your Fitbit Air measured overnight and tells you whether today is a day to push or to recover. Everything is calculated on your iPhone.

A woman runs through a park and gives a thumbs up — **72%**

Recovery
72 %

Sleep
88 %

Strain
target 14.4

You can train hard today.

One reading, six answers.

Every value is compared with your own 30-day baseline, not with an average of other people.

Recovery

1–99 %

How ready your body is, from HRV, resting heart rate, sleep and breathing.

Strain

0–21

Your cardiovascular load for the day, with a target that moves with your recovery.

Sleep

h:mm

How much you need, how much you owe and when to go to bed tonight.

Biological age

years

Your VO₂max and HRV against published norms for your age and sex.

Migraine risk

low–high

Short nights, stress or a drop in air pressure. It learns your own triggers.

Health monitor

range

Flags when your resting heart rate, HRV, breathing, SpO₂ or temperature leave your normal range.

A man stretches his leg in a park before a run

Not too much, not too little.

Your morning recovery tells you what kind of day suits you.

67+Ready. A good day for a hard workout.
34–66Moderate. Train, but listen to your body.
<34Recover. Easy movement, water and a good night.

Your data never leaves your iPhone.

No servers

Everything is calculated and stored on your phone. We have nowhere to receive your data.

Read-only

The app reads Google Health to show you your metrics. It never writes or shares anything.

No tracking

No ads, no analytics and no accounts. Details in the privacy policy.

Try it before anyone else.

Know your Limits is in testing. Write to us and we will let you know when TestFlight opens.

I want to try it