I have had this happen recently. I still haven't figured it out, either. I did find I wasn't sleeping as well, and I was really tired during the day due to my job. It took almost a week for the numbers to normalize.

Do you take any over the counter meds? Have you changed the amount of exercise you are getting? Might you be getting sick?

I did increase my exercise level. I started P90 so I'm active 6 days a week now. I just started the program on Friday.

How long after exercise are you checking your bgl ?

Your muscles store glycogen for energy reserves. When you stress your body doing intense exercise (P90X, etc.) that glycogen is converted into glucose. This of course elevates you blood glucose level. It's OK, it should drop back down within a couple of hours. Muscles will convert glucose to glycogen to for muscle repair and energy storage. This is a good thing as it can lower your bgl. A consistent exercise routine can help with stabilizing blood sugar levels.

I would keep exercising and keep monitoring (being mindful of the timing of the bgl tests relative to exercising). If it continues to go up go see your doctor.

"Oddly, I ate 20 g carbs for breakfast and after two hours got a reading of 145. I ate 38 g carbs for lunch and got a reading of 121. Go figure. "

The difference in your blood sugar readings could be due to several things: perhaps you were active between breakfast and lunch and your pre-lunch blood sugar was already lower. It might be just the way your body processes carbohydrate at different times of the day. Perhaps you had more fiber in the lunch meal than breakfast, and that slowed down any increase in blood sugar. And of course sometimes we just don't know why there's a difference. ~Lynn /Glucerna

I have also found that when I have seasonal allergies or something else that affects how I feel without really being 'sick' my blood sugars can get a little out of wack. I don't know if it is just because I don't sleep as well or because I might take OTC meds. Usually they come back to my regular range once whatever the problem is passes.

BG and exercise is something of a mystery to me. I know it can make it rise so that if I measure within an hour or so of stopping my reading is high. I also know that almost every hypo episode I've had has come during exercise. If I am in doubt I check my BG before starting and make sure that my levels are high enough. And if I feel even the slightest bit 'off' when I'm done I check again to make sure I'm not hypo.

My body definitely processes carbs differently at different times of the day. The morning is my least tolerant time, so I try to make sure I have lots of protein with whatever I eat. Also between breakfast and lunch is my largest meal gap of the day. Afternoon is when I am likeliest to be low, I have to add carbs to lunch or I can by low at my 2hr post lunch check. Go figure....