Vivoactive 5 blackscreen

It happens every now and then that the screen of my watch is completely unresponsive. I know the watch is turned on because I can start recording a walking activity by pressing the buttons, but there is no way to get the screen back on.

I tried restarting it once when this happened, but ended up sending an emergency alert to my emergency contacts...

This is pretty annoying for me since I use the watch to check my sugar levels (I am diabetic) without having to look at my cellphone.

The screen always starts working again after a couple of hours without any intervention. Is there a way to avoid this problem?