Higher BG after exercise

[Bogie]

Now that snow has arrived here in mid-Ontario Canada, the annual season of snow shoveling has started. When I rose this morning my BG was 6.5 mmol, but after exercise by way of a lot of snow shoveling the reading jumped to 7.8. Did not have anything to eat before the exercise.

Would I be best to have something to eat before the exercise? I usually have a Diabetic Boost meal replacement drink for breakfast after getting up in the morning but didn't today until after exercise. The drink is 16 carbs. I am assuming that exercise on an empty stomach after no food for about 9 to 10 hours makes the body seek the energy it requires through conversion of body fat, or whatever, for heavy work/exercise - therefore increasing the BG level. Am I correct in assuming this?

 

[Guzzler]

It is more likely to be what is called a liver dump and yes, this can happen with strenuous excercise.
The liver will dump glucose into the bloodstream as and when it detects a need for it.

 

[brassyblonde900]

Because you are yet to have breakfast, you are in an over night fast, This meant you had no insulin on board, to deal with the glycogen your liver dumped into your system by a process known as gluconeogenesis.
The rate of gluconeogenesis is 4x the rate at which skeletal muscles takes up glucose during exercise. This means you will likely end up with high BG due to the strenuous exercise on an empty stomach.
Our body perceives exercise as a stressful condition, and releases a bunch of stress hormones called catecholamines.
These have the effect of making the liver to dump glycogen to prepare us for the perceived fight or flight .
But due to your overnight fast, there was no insulin to deal with it. Hence the higher BG reading.

 

[Bogie]

It is more likely to be what is called a liver dump and yes, this can happen with strenuous exercise. The liver will dump glucose into the bloodstream as and when it detects a need for it.

That is what I thought might be happening. Probably best to have my morning supplement drink before braving the Winter elements and shovel snow. Not supposed to do this at my age, despite my high energy and not feeling my age, but youth/kids no longer want to work by offering to shovel your driveway and sidewalks for income. Because I have arthritis I am willing to pay a decent rate but no takers and we have lived in our townhome condo community for 25 years now. Today's youth are spoiled and feel entitled ... too demeaning to actually work physical labour. Our driveway is almost covered by our mini-van and when backed out of the driveway there isn't much left to shovel except after a heavy snowfall.

 

[Bogie]

Because you are yet to have breakfast, you are in an over night fast, This meant you had no insulin on board, to deal with the glycogen your liver dumped into your system by a process known as gluconeogenesis.
The rate of gluconeogenesis is 4x the rate at which skeletal muscles takes up glucose during exercise. This means you will likely end up with high BG due to the strenuous exercise on an empty stomach.
Our body perceives exercise as a stressful condition, and releases a bunch of stress hormones called catecholamines.
These have the effect of making the liver to dump glycogen to prepare us for the perceived fight or flight .
But due to your overnight fast, there was no insulin to deal with it. Hence the higher BG reading.

Thanks for the detailed explanation! Gotta love this forum

 

[Zilsniggy]

The drink is 16 carbs. I am assuming that exercise on an empty stomach after no food for about 9 to 10 hours makes the body seek the energy it requires through conversion of body fat, or whatever, for heavy work/exercise - therefore increasing the BG level. Am I correct in assuming this?

No, if you eat carbs the body will access the glucose from the carbs first, as this is the body's preferred fuel. So by having your shake, this is defeating that object.

I'd suggest having a proper breakfast, say eggs, rather than a shake containing 16g carbs, and goodness knows what else. That may stop the liver dumping so much glucose into your system.

Any exercise can be seen as the body as a stressor, leading to cortisol release, which in turn raises blood glucose, which you don't want on top of your liver dump. Your fasting glucose was still a tad high at 6.5, I'd work on getting that a good bit lower, as well as your HbA1c.

 

[Md2t]

That is what I thought might be happening. Probably best to have my morning supplement drink before braving the Winter elements and shovel snow. Not supposed to do this at my age, despite my high energy and not feeling my age, but youth/kids no longer want to work by offering to shovel your driveway and sidewalks for income. Because I have arthritis I am willing to pay a decent rate but no takers and we have lived in our townhome condo community for 25 years now. Today's youth are spoiled and feel entitled ... too demeaning to actually work physical labour. Our driveway is almost covered by our mini-van and when backed out of the driveway there isn't much left to shovel except after a heavy snowfall.

I would agree, as you did, with the first responder's suggestion that your immediate post-exercise reading was caused by gluconeogenesis in the absence of insulin, but that begs the question of how soon your pancreas responded by secreting insulin. Did you do any subsequent readings before you next ate? It may be interesting to try a couple of readings after your next bout of strnuous exercise to see how soon the dumped glucose was dealt with.

Don't trust me, I'm not a doctor! (Sadly some doctors are less trustworthy than others - They would do better if they listened to Ontario nephrologist Dr Dr Jason Fung and his Intensive Dietary Management director Megan Ramos).

I was rather worried by the readings in your signature until I looked closely and realised the more recent ones are listed first. You have done very well with weight loss and Hba1c reduction. Congratulations! My progress was similar, thanks to the advice from Dr Fung and Megan and it was a great pleasure to meet them in person when they visited the UK. You are very fortunate to have them in Ontario.