thank you Dr😊

OK, if you have been evaluated previously and the reason for lowered baseline is known, that is a good thing. If not, make sure to know the reason. There are series of tests to help us know the reason for decreased heart rate, including 24 HOURS ECG(ambulatory ECG), ECHO etc. So, kindly consult your cardiologist. generally, heart rate decreases in sleep. But, as i said, do consult cardiologist and don't forget to take your parents pulse too, as sometimes, it could be genetic inheritance too(rare though).

i have smart watch that keeps record of my heart beat..its says my resting bpm is 60 to 66..but sometime its records low upto 37.

So, what is the normal baseline heart-rate? Are you an athlete? 37 is a real danger, kindly evaluate with a cardiologist as early as possible.