I hope you aren't miffed at me, or that I don't confuse you....I'm really trying to get to the nut of your question. Your watch may or may not record both blood PRESSURE (BP) and heart rate (BPM, or beats per minute). It might also be able to record an ECG like my Galaxy watch and the Apple watches can, the ones produced in the past four years roughly.

Heart RATES as low as 40 may not be terribly worrisome, but they are in the range of 'bradycardia', meaning slow....too slow. That is going to cause you to feel dizzy and possibly fall, especially when you rise from a chair or from bed. It may be caused by the metoprolol you are taking, and you should be closely monitored for low blood pressure, probably caused by a low heart beat. This is only a guess....I don't know you and haven't been observing you. But your cardiologist or physician needs to know immediately if you are having these symptoms. It's good that you are getting a monitor to wear...a Holter monitor probably.
It is possible you have an arrhythmia. When a heart has some types of arrhythmia, called tachyarrhythmias, it speeds up. This would be the higher rates you have noted. Again, the Holter or loop recorder will note when it happens and the cardiologist will learn and know what to do for you. Meanwhile, you'll just have to learn to rise slowly, with support, and make sure your feet want to stay under you before you take too many steps away from things you can use for support. You do not want to fall!
One tip is to pretend half-stand, then sit again, then half-stand once more, to get your heart pumping a bit more steadily and to pump up your blood pressure. Do this when getting out of bed or when getting up from having been seated for more than a few minutes.
Good luck to you!