Activity related high readings in the morning

I am type 2 for many years and recently started using Freestyle Libre. The one thing that stands out to me

is glucose goes up as soon as I get up in the morning. The more active I am the higher it goes up.

I went out and cleared snow before breakfast and without coffee it went up over 200.

I use Lantus and Metformin at night as well as NovoLog at meals.

I don’t understand this.


Well there are a couple of things going on in my estimation. The first is the increase in your blood sugar when waking up. This is generally called the Dawn Effect, and in my son we have a pretty big increase in his basal’s to handle it via his pump.

The second is you did a bit of anaerobic exercise. When you do anaerobic exercise you may see an increase in your blood sugar as your body converts the glucagon stored int he muscles into glucose for energy. You should also see a pretty strong decrease in your blood sugar as your body replaces their energy stores.

Everything you are seeing sounds very familiar to me, the next question which is a bit more difficult is how to deal with these activities without having the corresponding increase.


Your body needs to fuel any activity you do. It will use a combination of whatever it has and whatever fuel will work - food you have recently eaten, glucose already in your blood, liver glycogen, stored fat, muscle glycogen, and in extreme cases, protein.

Your body needs insulin for the first 3 fuel sources I mentioned above - food you have recently eaten, glucose already in your blood, and liver glycogen.

In your example, if you do a somewhat strenuous exercise like that without breakfast and without insulin, your body will release liver glycogen for fuel. That 200 is the result.

There are ways to make this better. You can eat first and have a little bit of insulin to provide fuel. You can take insulin to counter the liver glycogen, but you would need to make sure you are going to get the liver glycogen response, and that is somewhat risky without a lot of practice and with the Metformin, as this reduces your liver glycogen response. Or you can reduce the intensity a little bit, and make it a lower effort, which would allow your body to use some of the other fuel sources available, like more fat.

Are you on a low-carb diet?

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Thanks Chris and Eric
You seem to be all over this. I have never learned so much in such a short time in all the years I have
been diabetic. Before I got the freestyle Libre I just took a lot of insulin and tested as little as possible since it made my fingers very sore. In the last three months I have been able to make adjustments in my management. I have reduced the amount of carbs I eat since I see immediately the effect of them and I have been able to reduce my insulin usage to less than half. I feel like I am just getting started. CGM is a real life changer for me.


You will definitely learn a lot on how to tailor your therapy with a CGM. We find it to be the single most important tool in our arsenal. Without it, you can’t see patterns. And of course, seeing patterns allows you to make the right choices for your situation. Some people like Eric figured all of this out using finger sticks. Others have been able to get there without sacrificing fingers.

Good questions you bring up btw.


It was for us too. We thought we were doing well prior to a CGM. What we have learned about D management (and wht it has allowed us to do) is still amazing to me. Congrats on getting on the CGM train!


Thanks Michel. I went to the doc today. I have lost 15 pounds and my A1c went from 7.3 to 6.2

I will never go back.


That is truly outstanding!!!

Congrats, that is awesome on two fronts! Keep it up!

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