Does exercise before any meals put blood sugar up?

I may have misunderstood the meaning of a morning fasting test. But I believe that a fasting test is just that, wake up and test straight away, before any form of exercise or food, even just taking a shower or getting dressed. I have found that I need to eat straight away after my fasting test to combat dawn phenomenon. I then shower and dress after breakfast. Exercise can raise blood sugars in the short term but is obviously good for overall health. As a Type 2 I perhaps need to be a bit more cautious than you, but still taking readings in a consistent manner is more helpful to see trends. Have you been testing before and after meals too to see what foods affect your blood sugars?

The affect of exercise on BG is ... it depends.

It depends on what exercise you do , how vigorous you do it, how fit you are at that type of exercise, how long you do it, what your BG is before you start ... and maybe when you do it.

For example, for me
- I can walk 10 miles and my BG is unaffected
- I can run for 20 minutes and my BG plummets
- I can climb for 40 minutes and my BG rockets

For me, my BG always falls slightly for the 24 hours following exercise.

Only you and your body knows. But don’t let it put you off exercise.

adrenaline levels play a part and the same exercise can have a very different effect depending on if you are feeling relaxed about it or stressed or excited.

In Type2 when our BG increases for any reasons other than food/drink, it is mostly due to our liver converting glycogen or fat into glucose. In both cases, the insulin sensitivity of our liver improves, so it is good to empty out our livers. (It is but more complex than this due to proteins being converted into glucose, but that can be ignored for this discussion.)

In Type1 often the liver does not store much glycogen, as very little insulin gets to the liver, but more glycogen is stored elsewhere in the body.

ringi said:

In Type1 often the liver does not store much glycogen, as very little insulin gets to the liver, but more glycogen is stored elsewhere in the body.

Click to expand...

Why does being type 1 make a difference?
What impact does insulin have on stored glycogen?
And where, if not in the liver, is glycogen stored?

My experience is when I exercise, my insulin becomes more effective and my liver releases more glycogen. As a result, for the next 24 hours, more carbs from my food are converted to glycogen and stored in my liver. This means, over that period, I have less glycogen to “drip” into my blood (reducing basal BG) and need less bolus insulin with carbs.

Exercise always drops me into the 4/5's and I always getting a better fasting result the next day.

helensaramay said:

Why does being type 1 make a difference?
What impact does insulin have on stored glycogen?
And where, if not in the liver, is glycogen stored?

Click to expand...

With Type2 you have about the same level of inslin in all your blood, everyone else has a much high level of inslin in the blood going to the liver, as the pancreas is directly connected to the liver. Hence the formation of glycogen in the liver is much less in someone with Type1.

Glycogen is also stored in the muscles.