I do fast walking, I was a competitive long distance runner, but now suffer with bad knees. So although I don’t run anymore I do fast walking. I do between 25,000 to 30,000 steps a day. It is the only thing keeping my blood sugars in check. Splitting the type of exercise I do into three groups, light, moderate, vigorous my exercises usually falls into a mixture of moderate and vigorous. If I‘m climbing a steep elevation , then I’m in the peak zone.
So on these higher effort days, I’ll use a recent example, my total time would be say 2h 46 mins, I spend 1 hr , 37 mins in the moderate zone, 51 minutes in the vigorous zone, and the remaining 18 mins in peak. Peak means I had a heart rate between 144 - 165 bpm. The peak zone would undoubtedly raise my blood sugars. If I was running that would be me sprinting, or you racing.
I’m not concerned about this temporary rise in blood sugars, as overall it’s increasing my muscle fibre, increasing my food, energy, oxygen efficiency , and burning fats. I’m maintaining my A1C’s just under the diabetic zone.
I might add, and you may wish to check your HR and blood sugars, but a long ride may raise your blood sugars temporarily due to body stress.