Emily’s Exercise BG Thread

I’m about to expose just how out of shape I am, which is pretty intimidating for me in this amazing group of athletes…ha, but here goes. As the weather starts cooling down, and reading through this category in particular (thank you, @Eric, for a lot of incredible information!), I am pretty determined to start exercising regularly, which for me probably will just be long walks, likely pushing a child (or two) in a stroller. In addition to BG concerns, I also have a muscle disorder that affects my muscles ability to create energy (a mitochondrial myopathy, for the curious), and a connective tissue disease that causes joint pain with exercise (not to mention the thyroid disease that contributes to the heat/cold intolerance the muscle disorder also causes), so I’ve pretty much just avoided regular exercise because it was already challenging enough before LADA came up. But I can’t deny the impact exercise has on my BG control. Tonight, for example…

I ate ~60 carbs for dinner (used Afrezza, so didn’t count exactly). Pre-meal 89, 1 hr post meal 96, at which time we went out for a more leisurely walk with the kids (about 20 minutes total with a ~8 minute rest halfway through for my daughter to run around a bit). By the time I got home, I was at 74. The meal I had usually would’ve caused a delayed spike due to fat content, but I tried to time the walk so as to avoid a spike when the Afrezza wore off (I was successful!).

Yesterday, I took a 10 min brisk walk starting at 178 with a 1.5u correction on board injected 40 mins prior, got home at 99. This has more often been the condition under which I actually walk - to bring down a high, with or without a correction.

I’ll probably have a lot of questions, but the main ones I was talking to my husband about…

If I’m only doing ~10 minute walks now, working up to at least 30 minutes over the next few weeks, do I still need to worry about refueling after (hubby thinks yes)? Along with that question, I read on one of the posts that it’s best to refuel within 45 minutes of end of exercise - what if your pre-bolus time now ranges from 30-45 minutes, depending on what you eat? I don’t want to dose while still walking since I already drop as it is. How do y’all manage the timing?

I’ll keep the questions coming as I think of them.


IMO, no. I’m no sort of competitive athlete in this decade but I run up to half marathons at least occasionally and run lesser distances on average several times a week and really don’t even consider “refueling”

Eric will be along momentarily to add up all the numbers and tell you it’s critical.

ETA— if you’re trying to shave 30 seconds off of your marathon time this sort of thing might be important. If you’re talking about taking a brisk evening walk for 20m after dinner, no I don’t think so…


Yes, you can replace muscle glycogen much faster if you refuel soon after you finish.


Walking is primarily going to be fueled by fat metabolism. If you are walking very fast or up hills, your heart rate could get into the zone where it uses more muscle glycogen. But in general, walking would be aerobic and would be much more in line with fat metabolism.

In case you haven’t see these, here are a few threads to review:

This image kind of gives an idea of how the intensity affects how you are fueling the activity. With running, there are actually calculations used for training that tell you where you are at 50% muscle glycogen and 50% fat metabolism.

A few more points - a) walking will lower your BG because your body will use any available fuel source it can, and if you have glucose available in your blood it will use that (and therefor lower you somewhat), and b) for the most part, you do not need to be too concerned with replacing muscle glycogen after less intense activities. You will use some muscle glycogen, but unless you are doing very intense walking, it will not be a glycogen depleting activity. Just general carb consumption throughout the day will top off your fuel tank.

For walking, the main benefit for eating carbs afterward is not so much for the muscle glycogen replacement, but to prevent the lower BGs that generally follow physical activity. So for something like that, you don’t need to be as concerned with bolusing, and then carbing up. You can eat the carbs to prevent the lows afterward, or eat carbs as needed if you start to go lower. The time you walk is also important. If you do it late in the evening, you may not get the low until you are asleep. So you may want to start a bit earlier until you are comfortable with how many carbs you need.

Exercise is a great fix for many things. I am happy that you are working on doing this. It helps in many ways!

Anyway, ask questions!


[scrap my post :-)] Sam and Eric are just too fast for me!

I’ll just add one reference from Runner’s World that I found interesting when I read it. It compares metabolic expenditures for running and walking:

We now know the relative NCB of running a mile in 9:30 versus walking the same mile in 19:00. Their male subjects burned 105 calories running, 52 walking; the women, 91 and 43. That is, running burns twice as many net calories per mile as walking.

The bottom line is that a mild walk’s net calorie burn is still half of that of a good run!


If you did decide to refuel – my son knows that his insulin time-to-activation is about 45 minutes, so, if he is not very active, it will take 45 minutes before his injections take effect. If he is very active (swimming), his insulin time-to-activation is more like 25 minutes. So he knows that, as long as he injects less than 25 minutes before the end of his exercise, he won’t see a drop due to his insulin injection.

You can figure out the same things: what is your insulin time-to-activation at rest and when walking? If you know that, you can time your pre-bolus so that you can eat right after being done walking.

As a note, my son found out that he only needs to bolus for 1/2 of his carbs right after exercise. You may have some ratio to look into for the pre-bolus you need if it is right after exercise.

Btw, like Sam and Eric, I figure you probably don’t need to refuel unless you eat super-low carb.


Just so you don’t think you are alone. The only way I am going to do a half-marathon is in the back of an ambulance and that would only be if the hospital is in the direction of the finish line.


Just wanted to make sure I was clear about one thing. I often write about how important it is to refuel after exercise. But when I am saying that, I am specifically speaking about situations where you are burning a lot of muscle glycogen and do it everyday. Like for Daisy Mae, that is important for her because she swims almost every day during the week. Without refueling sufficiently, by the end of the week, her muscle glycogen would become somewhat depleted.

If someone were to exercise intensely once a week, it would not be as important to refuel for the sake of muscle glycogen replacement. Because they would have a week to replace their muscle glycogen.

The same for less intense activity, which does not use a whole lot of muscle glycogen, but uses mostly fat metabolism for fuel.

But the important thing to consider for daily walking is just to make sure you are providing enough carbs to prevent the low BG that can happen. Any exercise, low or high intensity, increases the rate at which insulin is absorbed. It multiplies the insulin sensitivity, and your insulin works much more efficiently.

Having carbs after a walk can be even more important if you are not able to adjust your basal insulin. You need the carbs to keep you from drifting low.

Anyway, in your situation, I would say that having carbs available after exercise is still important, but it is important from a perspective of having a safe BG, rather than having them from a performance perspective. For the most part, once you increase your activity level, you have to either lower your basal or take in a bit more carbs to compensate. So I think in your situation you are not using a pump, right? That is why carbs are still going to be a useful thing for you after you finish.


So…I have had 20 g carb more than I bolused for this morning (thinking I’d rake some leaves) and am still hovering about 90. Does that indicate that I haven’t been replenishing adequately or “just” that insulin sensitivity is better? Oh yeah, I meant to start a temporary basal for raking but forgot…


It can be either one (or a combination of both).

During the process of rebuilding your glycogen stores, PWDs will generally have lower BG than they would if they were not rebuilding them. Your muscles will grab what they can to rebuild.

The other thing is that immediately after exercise you have a faster rate of glucose uptake because of an increase in insulin sensitivity and because of the increase in the concentration of the glucose transporters that are associated with the plasma membrane of the muscle.

So in this situation, it could be either or both.

As a side note - muscle glycogen is not shared, but liver glycogen is. Your body can use liver glycogen for any activity, but the only muscles that can use the muscle glycogen stored in your arms is your arms. The only muscles that can use the muscle glycogen stored in your legs is your legs.

So you can deplete your arms rowing a boat one day, and then go biking and deplete your legs. Muscles don’t share their muscle glycogen with other muscles. :slight_smile:


I am guessing it is a bit of both.

Yep, edited my reply. Thanks.

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I am, too - I’ve discovered I actually LIKE walking, which I never have when I’ve tried before (all the times I’d tried had been before one or another health issue was under control, so symptoms were just in the way).

What if my mitochondrial myopathy causes tachycardia - do you know if heart rate being up even with lower intensity would use more muscle glycogen?

That’s a good idea!

@Thomas, LOL! That was definitely me prior to now.

That’s part of why I’m glad I’m not yet on basal - don’t have to factor that into the equation.

Thanks for all of the input! I’ve had a really hard time with energy this week (hosted family over the weekend plus starting the walks), so we’ll see how I have to adjust things to deal with the mitochondrial myopathy.


I am sorry, I wouldn’t even want to venture a guess on that. :frowning:

Not a problem - that’s why I phrased it as a “do you know.” Hardly anyone knows when it comes to the mito issue! :slightly_smiling_face:


i fit the same bill. after my swim, i bolus 1.6 units for 32 gms of carbs (chocolate carb/protein shakes by BOOST (Nestlie). that comes to exactly 50% of what i would need if i weren’t having them right after exercise. and i pre-bolus only 15 minutes as opposed to 20-30 minutes. everything is heightened by exercise.


So after an embarrassingly long silence, I’m reviving this thread…

I have been doing some research on exercise recommendations for people with muscle myopathies because I am determined to figure all of this out this year. One of the things I’ve come across is to first build up endurance with weight training, then switch to aerobic endurance exercises to improve mitochondrial function (actually it increases the number of mitochondria also). I have jokingly told my husband I’ve already done weight training by lifting and carrying my 35lb 21 month old around every day… :wink:

The other recommendation I’ve found is to do 2 hours of exercise a week, preferably on nonconsecutive days, so that is going to be my end goal. For now, I’m going to shoot for 1 hr a week (split into 2 nonconsecutive days). My husband and I joined a gym, so we’ll see how that goes. They do have various classes included in our membership, and I’m very interested in yoga, so I might try that out, too, at some point.

One question I have is - for someone just starting out with an exercise routine (who has zero experience with exercising, unless you count Wii sports a few years ago :rofl: ), what would you recommend as far as what to track, how to prepare, etc? As far as my BG goes, right now I’m just planning to take some fast carbs with me in case I drop, and I’m going to record how different exercises affect my BG as I try them out, and make a plan from there. Honestly, I feel awkward enough even going into a gym since I’ve never set foot in one nor used public exercise equipment before…


It depends on the type of exercise. Are you planning aerobic cardio stuff?

Are you on basal insulin now?

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Yes. Initially my workouts will be primarily weight training with some walking/cycling after, and eventually flip to primarily the latter.

Again, yes, I’m on Tresiba now, though a very low dose (just 4u).

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Since you can’t easily adjust the Tresiba, the only thing you can really do here is test and treat. A small snack before, and treats as needed during.

Over time, with a consistent exercise routine, you may see your Tresiba dose need to be reduced. So make sure you reevaluate that as needed!


@Pianoplayer7008, fwiw, I’m rootin’ for ya!

Also, you are so much better prepared for exercise than I was back when I started on insulin. Newly diabetic, no CGM, trial and error for shots, and added exercise bc that seemed like a good idea. It was a good idea, and I survived it just fine. Nothing scary happened. I just tested before I started and anytime that I felt weird during exercise. I was doing jogging, biking and weight machines at the time. So a decent mix of activities.

You’ll figure it out! And at the very least, I know you’ll stay safe while you’re doing it. I always prioritized safety over tight numbers…and if I could get tight numbers throughout all of the activity changes, all the better.