Hi I Have A Sleeping HR Of 41 Judging By

Hi I have a sleeping HR of 41 judging by my Garmin wrist watch. RHRate during the day is between 60 and 70 rises to 140 at time if Im exerted. the watch is new I exercise 3 times a week im reasonably fit im not a coach person. what do you think about the accuracy of these watches the 41 was a shock