Exercise

I’m only doing small amounts of exercise in one go at the moment (post heart attack) but I find I go up a bit too, but it comes back down within about an hour. Maybe someone with a Libre has the same thing happen and can see an exact pattern? (Getting one on Tuesday so I’ll report back if no one else does!) I can sort of see why it’s happening though. Don’t know the exact terminology but could it be related to the fight or flight response? - Suddenly there’s a need for more energy so your liver rides to the rescue, so to speak?

Exercise can raise blood sugar in the short term. The body releases glucose from stored fat. I know of a couple of non-diabetics who wore CGM's during exercise & saw their glucose spike into the 9's.
Have to think of it as the long ball game as it levels out over 24 hours.
Have a look at the following.

https://www.healthline.com/diabetesmine/ask-dmine-diabetes-exercise-blood-sugar-spikes#2

Your liver is giving you sugar, which you don't have enough insulin to cover. I have been taking a unit or two of fast-acting insulin with my morning coffee and cream (I fast until 3pm), which means I can stay level even after exercise, like running or walking 15km. I tend to sit at 5 mmol/l.
At night I'm too insulin sensitive to take any correction before running, so have to take a unit or two after I run to stop my blood sugars from rising.