Discussion of "Predicting BG moves up or down during and after exercise" wiki

it would be nice to shorten the title/ question.

Yes, I couldn’t figure out what to say for that title to include “during”, “after”, “up”, and “down”…

How about “why can my blood sugar be unpredictable”?

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Ha! There isn’t enough room on the internet for that!
Often times we may not know all the reasons for what happens, and that can be termed as unpredictable, but I tried to avoid the word unpredictable because that is what I am working on - trying to make it predictable

I think we should have “exercise” in there somewhere, because otherwise it opens up the title to all kinds of BG fluctuations.

How about:
Trying to predict blood sugar during exercise?

Exercise and Blood Sugar?


Blood sugar varies with exercise?

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Oh gosh, where do we start…

Holy cow, yes! :scream_cat:

Good one, @Irish! You got us all for a while :slight_smile:


@Eric: I slightly annotated your great write-up. See what you want to take/leave in these suggestions. I used strikethru for negative corrections, underline for additions.

During and after exercise - why does my blood sugar sometimes go up, and sometimes go down?

Different types of exercise will affect you in different ways. For example, if you are doing a very easy activity, you will be using more fat metabolism to fuel the event, and you might not see a rise in blood sugar. If you do a harder, more challenging exercise, your body will be using more muscle glycogen, and thatwhich might cause more of a blood sugar spike after the exercise. If you are doing very hard exercise that is shorter and very intense, you may see the spike during the exercise.

Going low or high during or after exercise has perfectly normal reasons that are perfectly normal. Your body responds in much the same way as a non-diabetic’snondiabetic’s body. The only difference is that the non-diabeticsnondiabetics don’t see their blood sugar rise or fall because their pancreas and liver take care of it automatically.

During intense exercise, it is common to need insulin because your body is trying to fuel the work, and also because of the cortisol and stress hormones that are released which will raise your blood sugar. During lower intensity exercise, the rate of glucose uptake from the blood is increased, which can cause a low.

Here are some very general examples of what might happen to a diabetic’s blood sugar after exercise. These thingstrends will vary greatly for each person depending on the intensity of the activity and a person’s fitness, so simply use these descriptions as a basis for understanding the different possibilities, and how they may apply.

Low Aerobic - energy is primarily supplied by fat metabolism, with only a small background of carbohydrate metabolism required. The initial perceived effort level (on a scale of 1 to 10) is between 3 and 4. Physical activity can increase the rate of insulin absorption and glucose uptake. Blood sugar can drop during this exercise, and can also drop after.

Moderate Aerobic - slightly faster than Low Aerobic. Energy comes predominantly from stored muscle glycogen, but the body is still metabolizing a fair amount of fat. Initial perceived effort level is 5 or 6. A diabetic’s blood sugar might drop during this exercise, but it can also rise after. When you exercise your muscles need more glucose to supply energy. In response, your liver increases the amount of glucose it releases into your bloodstream, which can lead to a post-workout spike in blood sugar.

Intense High Aerobic to Anaerobic - muscle glycogen provides virtually all of the energy for muscle contractions. Initial perceived effort level is 7 or 8.Intense exercise causes the release of hormones that increase the release of glucose by the liver, and reduce the muscular uptake of it. By releasing epinephrine (adrenaline), noreepinephrine, cortisol. Your heart rate and blood pressure increase, the amount of oxygen flowing to the tissues increases, and your liver’s glycogen stores are put into action giving you fuel. It’s the typical response the body has to a “fight or flight” situation. Imagine if you are about to be attacked by a grizzly bear. Your body would prepare for that by providing fuel and doing those things mentioned so that your would have everything you need to either fight the bear or run away. Ultimately what you will see is an immediate rise in blood sugar.

Several other factors can affect blood sugar during and after exercise:[possibly use bullets for the points below?]
Performing exercise yesterday may also cause lower blood sugar today, because the body has not completely replaced the muscle glycogen and is relying more on the blood glucose uptake to fuel the exercise.

What can make it even more difficult to predict is that the previous day’s exercise and blood sugar can also affect what happens today. Having low blood sugar yesterday can blunt the body’s hormonal response to exercise today, meaning the hormones that would usually raise your blood sugar are not as active. Exercising on the day after severe low blood sugars should be done with extra caution and frequent testing.

The location of the pump infusion site or the injection site used can affect the rate at which insulin is absorbed. Using the muscles that are near the injection/infusion site will increase the rate of insulin absorption and bioavailability of the insulin. Consider the difference an infusion site would have on a leg versus an arm when bicycling!

Temperature can also affect insulin absorption. Higher temperatures will increase the absorption rate and bioavailability of insulin. Heat causes blood vessels to expand, so this should be considered when exercising in hot temperatures, or doing an activity such as hot yoga or using a sauna or hot-tub after exercise.

Even the order that exercise is performed can affect the blood sugar that follows. Doing aerobic exercise first followed by anaerobic exercise can cause blood sugar to be more likely to trend down after the exercise. If done in the opposite order, anaerobic first and then aerobic, blood sugar might be more likely to trend up. (This, of course, depends on individual factors such as the intensity of exercise and the amount of insulin and carbs, so this concept is mainly useful for comparing the results the exercise order will have when performing different types exercise.)

One of the best tools the diabetic has is keeping good notes! Keeping track of different types of exercise, and how they affect the blood sugar makes it easier to decipher the mystery.

Once you understand how and why your body reacts to specific exercises and intensities, you can better predict and compensate for your blood sugar changes, up or down, during and after exercise.

I am ok with everything you edited, except for 2 things.

I took out the part about me at the beginning. I am trying as much as possible to avoid the pronoun “I”. The only exception was that post that I sent you the other day where I gave examples.

The ending I slightly modified. I said “you can better predict and compensate” instead of the “you should” phrase. I personally don’t like when people tell me I should do anything!

Anyway, take a look at my edits, see what you think.

Hey Eric,
These are really great insights. Is there any chance we could add citations to this somehow? Are there specific books or training manuals you’ve taken this information from?
That would be really helpful for readers who want to learn more.

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I am fine with anything you do :slight_smile:

That said, I disagree with your concept of not putting anything personal. We are not doctors and medical professionals. So we cannot provide the “professional,” rated opinions that are able to take advantage of our recognized status. For these, avoiding the “I” makes sense.

For us, on the other hand, we are only credible because of what we do ourselves. We respect your opinion, Eric, because of all that you do. It is MUCH more credible, and also much more impactful to the individual diabetic reader, when he/she can connect with what you say because of your personal statements.

For instance, there is one thing you told me early that has “qualified” you in my eyes to a degree you cannot imagine. it is when you told me about that marathon where you started at 60, but KNEW that, if you ran harder for a while, you would go up – although your wife was asking you to stop the race! This story is what crystallized in me the fact that you KNEW more than most anyone I know about exercise. You could never have created this certainty in me in any other way.

So this is why, imho, you should put the “I” in your wikis, along with the personal stories. Every time you write an anecdote about yourself in a wiki, you gain a huge amount of cred with the reader: they can connect with both what you say and what you know.

People connect emotionally, not with their reason, because, in the end, we are still forged by millions of years of evolution as little bundles of emotion with a very thin layer of reason :slight_smile: So, you need to give them reasonable arguments, but you will get the belief and the credibility through the personal stories and statements that they can connect to :slight_smile:

In the case above: I am fine with anything you do! My suggestions are just that. But I am convinced that your wiki would be much more powerful if it had more of your own results and yourself in it!


I agree with @Michel.

Also, I wasn’t trying to be funny. I was proposing a new title…

Blood sugar varies(variance) with exercise.

Sorry for the rogue question mark. I can see how i confused everyone.


Thanks, I appreciate what you are saying. I am just trying to make sure it relates to the reader and not to me. I try to speak in a way that puts the focus on them, not me. That is what I am trying.

But I can understand what you are saying. Maybe different types of posts have a different type of perspective. Like when I am talking about what I use for testing when running, I can say “I use this type of meter”.

I can try to find things, but citations are difficult, because things I have learned are from reading multiple sources, over many years. So I don’t have only one reference to cite. But I can try to find pages to reference.

I don’t ever listen to only a single source. If one person says it, so what? But when I read the same thing over and over from many different people, AND it matches my personal experience, AND it makes sense…that is when I start to believe it. But sometimes that takes months and by the time I start to believe it, I haven’t kept track of all the people who said it. Hope that makes sense!

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I think that if they can connect emotionally with what you say you will gain them faster/ better.

I give a lot of speeches and presentations. I have learned through these many years that it is not the general points I make that count, but the stories I give to illustrate them, which make my points connect with the audience.

For instance, if you read the post I wrote above, what is more impactful to the reader, and will get her/his buy-in?

It is the story about you, your wife, and the marathon.

It is the story that gets the buy-in, not the opinion :slight_smile:

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@Eric, yes I understand it can be tricky. Even a few sources would help, even if they’re not the only ones you found the information in. Personally I’d love to read some books on D & exercise because our son will probably start doing organized exercise in the next few years, and I’d like to better understand the biology. We had a fairly disastrous experience with snow and altitude so next time I’d like to be better prepared. I’m also still trying to figure out how his “gymnastics” class affects his blood sugar.

Ok, I will work on it that way a little. I just don’t want to talk about myself too much.:wink:

A lot of what I have learned is from sources that are not diabetic specific.Things like Runner’s World magazine and Nancy Clark’s book.