Marvin does not know what he is talking about. There is nothing about DND that will stop the sensors from thinking you are asleep when your vitals are low enough to register as sleep. DND is only to prevent notifications and phone calls from disturbing you when you do not want to be disturbed. What you should do, if this is a frequent occurrence, is either take the watch off while you are relaxing, or put it in power saving mode and set the power saving to limit the health features. You will, of course, have to remember to turn power saving off before actually going to sleep. Since only one mode can be active at a time, and routines to do not apply to the watch, you might make a power saving mode, whereby when you are relaxing and want to turn power saving on, instead of rooting around in the settings. You will have to turn power saving mode off before you can turn sleep mode on (assuming you use sleep mode). If you don't use sleep mode, just turn power saving mode off when you go to sleep otherwise your sleep will not be tracked and your sleep score will not be calculated. Create the mode as follows:
Turn on manually
Choose what this mode does = Galaxy Watch = power saving (so that the power saving only applies to the watch). Then turn the mode on, when you are sitting around relaxing.
