Good video that has a lot of good information and anecdotal evidence for Continuous Glucose Monitors (CGM). Covers hyper and hypoglycemia.
My glucose will rise slightly during exercise but within a half hour will drop significantly. Perfectly normal according to this video.
I do not use a CGM.
https://www.youtube.com/watch?v=2XJup5NOYT4&t=1797s
John