@TwoTone - When reading on here, and from my own personal experience I find strenuous exercise, such as HIIT and the like to create interesting blood glucose patterns over the course of the day.
For example, if I have steady, but relatively gentle exercise, like a brisk walk, gardening or the like, I find my blood sugars lower, noticeably, almost immediately. If I do something heavier duty, like cycling uphill, into a wind, sail change, or the like, my blood glucose numbers go up in the immediacy, but a short while later reduce to slightly under my daily averages for that time of the day for the rest of the day. If that exertion is later in the day, the lower number can carry over into the next day.
I'm not suggesting you necessarily make any changes from what works for you (why would I?), but if ever you are trying HIIT, or the like, again, it could be useful testing fairly intensively for the rest of the day.
If you are testing intensively again, over several days, for whatever reason, you might find using a Libre sensor could give you are fabulous insight into what's going on, for a period of 14 days, 24/7.
I found my dabbling with the Libre to be hugely educational, even after living with diabetes for some time.
Keep fighting the good fight!