Post morning exercise hyperglycemia

     I am 21 years old and have had diabetes for almost fifteen years.  I usually stay in very good control, and generally have very good A1c's.  I used an insulin pump to control my blood sugar because I find it easier to control while exercising.  I run about 5 miles a day, usually in the afternoon.  I avoid a hypo by reducing my basal rate down to 33% two to two and half hours before my run, and make sure the last meal has been at least two hours ago so that my meal bolus is done working by the time I head out. This works great in the afternoon.  My blood sugar is most predictable during this time.  However, when I follow this same regimen in the morning, after breakfast, I come back with a good blood sugar and find that two or three hours later, my blood sugar sky-rockets to sometimes 300.  This does not happen later in the day.  Does anyone know why this could be, or have any suggestions to keep this from happening?

[Forum-vol-cmb]

I don't know all the exact science of why this happens, but I do know that this has happened to me before.  I like to run in the morning, so I make sure I have a snack before I go to bed so that my blood sugar is not too low in the morning. The snack is usually a protein or a mix of carbs and protein.  I check my blood sugar first thing when I get up and if I need to eat some carbs so I can run, I have a small glass of juice.  (I do not use the insulin pump.)
I wonder what you are eating for breakfast.  If I eat certain foods, for example pretzals, my blood sugar will be fine and then 1 or 2 hours later I will have a high blood sugar which I will compensate for with a unit or two of insulin.  I have learned that if I give more than that I end up with a low.  
I am wondering if you are female? Hormones can play a huge role in your blood sugars as well.  Different times during the month I have to compensate with more insulin because I am ovulating.  If you are male I would assume hormones play a part as well, I just don't know much about the effect of male hormones on a diabetic.  
Another thing to think about it even though we strive to have perfect control--sometimes we don't for a number of reasons and factors out of our control.  You sound like you are taking excellent care of yourself.  I feel your frustration because I get frustrated when I feel I have done everything I should and I still get a crazy reading.

[kstreeter513]

I am a male.  Usually for a pre-run breakfast, I have a whole wheat english muffin, with peanut butter and jelly, and a glass of skim milk.  I also notice, by the way, that even in the mornings that I don't run, 1 unit of insulin covers only 10 grams of carbs, whereas 1 unit in the afternoon or evening covers 20 grams of carbs.  My insulin to carb ratio is half that of the morning as in the afternoon.

[JDRF-VOL-SG]

I believe this issue has been brought up before, and it is a question that really confuses people who are doing everything "right" only to find those high levels after exercise. I have read that the source of the problem is the dumping of adrenalin which acts to block the effectiveness of insulin. As long as this stress hormone is present, high glucose levels will happen, and when it dissipates, a low can result. There is no real solution, and you just have to realize that it is likely to happen and take extra insulin when it does, keeping some emergency carbs handy in case a low follows.

[kristin306]

If your insulin to carb ratio is different in the morning compared with the evening, that probably means that insulin is less effective for you in the morning hours (I believe that this is related to the 'dawn effect'). Perhaps you do not need to decrease your basal as much when you run in the morning (so get more insulin during or rather after your runs).

Exercise makes the effect of insulin more dramatic, but if you have way too little insulin in you, exercise can make your blood sugar go up quickly. It has also happened to me before.