Managing a heavy caloric output

I’m 72 years old, and just diagnosed (6 weeks ago) with T1D. I’m an experienced, if mediocre, athlete from some time back (best marathon 2:58, for example). But I don’t yet have much experience as an athlete with known diabetes.

I’ve had a 1-1/2 year battle with leg cramps. Nocturnal leg cramps had me sleeping in a chair, and I had to give up Orange Theory Fitness workouts because of three episodes of severe exercise-induced cramps. When I say severe, I’m referring to 10-15 minutes before ability to stand up, 30 minutes before I could walk, and two weeks before I could work out again.

It now appears that these problems were a result of my developing but undetected diabetes. Nocturnal cramps are essentially gone, starting a few days after I started insulin. I’m now ready to try Orange Theory Fitness again. However, I’m concerned about how to manage my first outing with such a heavy caloric load. Obviously, I’ll start with a relatively easy workout, but I was generating 700-800 calorie workouts, so even an easy OTF workout is going to be a bigger event than things I’ve been doing on my treadmill and recumbent bicycle at home.

I’m looking for suggestions about the best way to manage this. Should I go right after a meal and not take insulin? Should I go when my blood glucose has stabilized at a low level after a meal, and try to guess the required intake and eat continuously (gels, most likely)? Is there some other approach? I’m mainly just worried about handling this right the first time. Once I’ve done it successfully, I’m sure it will be easier. Any assistance would be appreciated.

Since posting this, I’ve discovered that there’s a separate Exercise group, and I’ve reposted it there, where it’s more appropriate. I don’t see a way to delete this one. Sorry.