I am not wearing the watch, and it is still measuring my heart bit. Is it a lie then?

Since an Apple Watch only takes this background reading when you're still, the time between these measurements will vary > Your heart rate. What it means, and where on Apple Watch you’ll find it

Any motion of the Apple Watch when you're not wearing it can affect the heart rate reading.

Mine does the same thing. You only need to be concerned with the reading when you're actually wearing the watch.

I've actually tested the heart rate app between my Apple Watch and at my physician's office. They are identical.

It may help to close all open apps on your iPhone and then restart both your iPhone and your watch:

- On your iPhone, double-click on the Home button, then swipe up on each app preview to close it;

- Turn both devices off together, then restart your iPhone first;

- To turn your watch off: press and hold the side button until you see the Power Off slider; drag it to turn off.

- To turn it back on: press and hold the side button until you see the Apple logo.

I suggest that you contact Apple Support (mail-in service may be available) or make a Genius Bar reservation with a view to having your watch checked under warranty:

https://www.apple.com/support/watch/contact/

hey_ana wrote:

I did all what you suggested and it's still measuring an inexistent heart rate. I mean, I have the watch on a table, literally.... and I tap on the screen so it can start measuring, the grey lights turn on, and it measures the heart rate... of the table I guess. How is it possible?

Apologies - I initially misunderstood what you were describing.

Whenever you manually tell Apple Watch to measure your heart rate (including by using the Heartbeat glance), then that is what it will try to do. The green LEDs will light up and the watch will try to take a reading. This reading (obviously) will not be accurate if you place the watch on a table at the time.

In respect of background heart rate measurements taken during general daily wear, with Wrist Detection enabled, your watch will not try to measure your heart rate at all when you are not wearing the watch, so your accumulated heart rate data - as shared to the Health app on your iPhone - will not be affected by irrelevant, inaccurate readings.