BPM between 40 and 180

I just checked and it seems that Apple watches cannot be used to record a reading of BP on their own....they can be linked to a regular cuff, maybe via an app.
My Samsung Galaxy watch, version 4, which I purchased in 2021, is capable of recording BP after a firmware update. I am reminded every 28 days (no idea why 28) through the Health App on my phone to re-calibrate the watch's sensor using an approved cuff device.
In case it is of interest to anyone reading in the future, a great time to get a solid read on your heart's health is just before rising in the morning. Prior to moving around and sitting up, use your smart watch to look at your waking pulse, and also your resting blood pressure. They should normally be in a narrow range, a range you will determine by keeping a record and running an average. Once you see a single morning's recording more than about 4% higher than the running average, it's a sign of an infection, inflammation, tissue damage, or overuse (meaning don't exercise that day...at all! Maybe not the next day either for extra insurance).

@gloaming "Once you see a single morning's recording more than about 4% higher than the running average, it's a sign of an infection, inflammation, tissue damage, or overuse (meaning don't exercise that day...at all! Maybe not the next day either for extra insurance)."
Were did you get this information? I would love to read the paper you lifted this quote. How about some links to peer reviewed articles. Right now this does not make sense.

You could look it up yourself. I don't do other people's homework or refutations. Later...

I have looked it up and could not find anything. What should I look up? Have you ever heard about heart rate variability? Now that is easy to find. This isn't about homework. You are on a site that is sharing information and in your case you hand it out like people should actually listen to you. You cannot just make made up 'scientific' statements with any science work to back it up. You owe it to fellow travelers to link what you are saying.