Over the holidays I have started running again - and I love it! But it's been doing weird stuff to my bgs. Before I run, I eat a snack with fast acting sugar and protein and set a temp basal for an hour so that I'm not getting any insulin. After running, I check and am usually a little low or on target. I set a new temp basal for 2-3 hours of about 75% of my normal basal rate, but I continue to go high - even up to the 300s!! Then all is good after a correction and a couple hours. However, in the middle of the night, I've been waking up feeling low and grabbing glucose tabs!
My first tip is to of course contact your doctor to hear a
professional's opinion who knows you! However, for me... I exercise
for one hour almost everyday and change my temp basal to 0% for three
hours (one before exercise, one during, and one after). It works
perfect for me and the purpose of these temp basals are to prevent you
to have to eat extra food for those lows. Sooo, maybe you can consider
trying not eating the snack OR up the basal and/or lower the hours if you're working out for 30 minutes, since it seems that's why you're going high. If you're not on the CGM, you may also want to be checking your BGs constantly to see how you're doing during these trials!
I second the suggestion for involving your endo and or a CDE who has some exercise background, too...Diabetes is complicated enough without slapping it around with a bunch of real life…
That said, keep in mind that your insulin takes about an hour to start acting so if you are lowering your basal right before you start to exercise, you may be eating because you need to (the lower basal hasn't taken effect while you exercise) and then you stop exercising right when the temp basal hits... seems one possible scenario, anyhow...
We are all so different that I am low on advice other than testing (a lot) and making sure that you are timing your insulin to meet your activity...
I'll be curious to see others' experiences and insights - sorry I don't have a lot to offer on this one....