Does this happen to you?

So i have noticed that when i do a high cardio or just a hard work out, usually it is zumba and hip hop, my blood sugar sky rockets into the 3 and 4 hundreds but its a false high and if i do insulin to correct it i will drop really fast. When i take a 20 30 minute walk around my neighbourhood i will automatically drop really low. I just wanted to see if this happened to anyone else.

Yes, I have experienced that; or something quite similar but less dramatic.

This phenomenon occurs mostly when aerobic exercise morphs into anaerobic exercise. During aerobic exercise we are burning available sugars which will generally cause our body glucose levels to go down, sometimes go quite low.

This is a non-technical explanation:
Because anaerobic exercise requires significantly more energy - read this as more fuel, signals are sent to our liver telling it to release glucagon the agent that tends to raise blood sugar levels. Did I say that correctly?

What I do on returning from what is for me a strenuous bike ride, I stop a few miles before finishing, check BG and eat a peanut butter & cracker snack [23 gm] and take insulin to fully cover the snack - this somehow signals my liver that exercise is over and return things to normal 0 well as normal as someone can be after almost 60 years of playing with T1.

See what works for you - be daring while being very careful with any experimenting.