Debugging running - the spinoff episode

As requested by @Eric, this thread is to document my attempt at a 10k in August!

Type 1 since 1995 (age 8), Medtronic pump user since 1997, CGM user since 2013, Tandem pump user since 2018. Exerciser since I was little. Usually I have decent A1cs (under 6 for the past few years thanks to ControlIQ).

I’ve done 5k races for a long time and just can’t seem to manage my numbers well or condition myself to run more. I started a 10k training plan a few weeks ago and am on the struggle bus - I’m having trouble keeping my numbers steady during a run, and recently have been having rollercoaster days on top of that. (Oh and it doesn’t help that every other week my body decides to react differently to what happens!)

Here is what I have documented so far (emojis to rate my overall workout experience that day). All runs documented; not all YMCA workouts.

5/11 - 2 miles :frowning_with_open_mouth:
4:15-5:15 - 40% basal; no food
5:25-5:50 - walk & run
Dropped right away, 30pts overall in 20 min. CIQ back on toward end of run

5/13 - 2 miles :neutral_face:
8:30-10:00 - 33% basal, 100% after 10 (CIQ off)
10:00 - Chewy bar 18g
10:08-10:36 - walk & run
Too much carb - rose too high, no drop

5/14 - YMCA workout :tada:
8:30-10:00 50% basal, then 100%
8:40 coffee with cream
10:00 cheese stick
10:00-11:50 walk, cardio, weight train, cardio, walk
10:40 sleep mode activated

5/20 - 2.5 miles :yum: needed a little more sugar at first
7:00-8:45 50% basal
8:20 1 date (10g)
8:26 dropping too much, CIQ on exercise mode
8:27-9:06 walk, run, walk
Dropped a bit; continued to drop after stopping
9:01 sleep mode

5/23 - 2.5 miles :neutral_face:
4:00-5:10 33%
5:18 two glucose tabs (8g)
5:19-6:00 workout
Dropped fast by mile 1.5
5:55 done, CIQ on

5/25 - 2 miles :neutral_face:
4:55 exercise mode
5:00 two glucose gummies (6g)
5:19-5:50 walk, run, walk
Dropped fast near the end
(1:30 small correction bolus)

I ate over 800 extra calories trying to balance the rollercoaster that ensued today. I’m tired of this!


So, I’m thinking as of now I need to decrease my basal a little more a little longer before my workout and then eat a little more (but not too much) carb.

I know I’ve changed a lot of variables in between each workout, which makes it harder to troubleshoot.

Thank you for any help in advance!

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I appreciate the documentation and notes, but do you have BG numbers to go with the times you are posting? It’s a little hard to decipher from the CGM trace what you were at the particular time.

Like for example:

From the image, I can’t tell where you were at that point.

Based on the times you are giving, I am assuming these are all morning runs? No breakfast and no IOB, right? Like basically wake-up and go?

Are the basal adjustments your own, or the Tandem CIQ stuff? Like when you say this:

Is that your own manual adjustment? Like, that is not a CIQ adjustment, only your own?

As an example, let’s go through this one:

Walk me through this one.

  • Did you wake up at 4am, and adjust basal to 33%?

  • What were you at 5:18am when you took the g-tabs?

  • Did you stay on 33% for the whole run? (If so, I gotta tell you - zero basal, the beloved “ZB” is totally where it’s at for exercise!!)

  • What was your level of effort on this run? Hard, medium, or easy?

The first mile or two is where a drop will normally happen. Your body has to transition from rest, and the easiest fuel source - the most readily available - is the glucose in your blood!

With non-D’s, their alpha cells have the sense to deliver glucagon and tell their liver to release some glucose. But our alpha cells are not so smart, they just snooze through it all. So we have drops in the first few miles.

This is 100% typical. But we can fix it.

General questions:

If you were to just wake up and NOT exercise, would your BG generally spike up from waking up? Like the somewhat common feet-on-the-floor spike that many people have?

What is your general diet like? Is it low-carb, normal-carb, high-carb?

Do you have a reliable meter so that we can get some BG numbers to go along with the rest of the data?


Whoo thank you for your reply and for reading all of that!

So the notes I made were only going to be for myself - I should have explained everything in more detail :crazy_face:

Yes, these are all morning workouts - no IOB. No breakfast but I did document if I ate something before I went (chewy granola bar, glucose tabs/gummies, a date, etc). The pictures with the time are when I was done with my workouts, if that helps. Maybe I could go back and find exact numbers in the software? The low line is 70, the high line is 135.

“33%” that means I turned off ControlIQ at the designated time and set a temp rate of 33% for whatever the time was I wrote. So for that example, I woke up at 4 and turned on a temp rate. Then went back to sleep and got up to run at 5:15ish.

Ok I logged into Clarity so I can give you exact numbers for this example! On 5/23, I set a temp rate to run for 70 minutes at 33%. When that ended, it went back to 100% basal rate. (FWIW I use ControlIQ in sleep mode around the clock normally.) At 5:18 I was at 146, when I ate the tabs.

I have one level of effort for running - just run! Haha. So for me that is about a 10 minute mile, and I have noticed my heart rate has been decreasing as I’ve been running more, so I could call it a medium effort run?

For your other questions: no feet-on-the-floor phenomenon anymore (likely thanks to ControlIQ). I eat no meat, about 270g of carbs per day on average per my LoseIt app.

I do have Contour Next EZ meter but only use it if I really need to - my Dexcom runs reliably unless I have a bleeder.


I am trying to look through the graphs and figure a few things out. Sorry, I have not ever used Tandem!

Is the vertical brown-ish line the time when you are in CIQ?

Also, is the timestamp on the top the time that it shows the last CGM reading, or is there a projection into the future?

Like in this image, is the time shown (9:11am) the time of the last shown CGM reading? Like here in my purple arrow, does 9:11am match up with this last shown CGM number?

Also, if you can mark on the graph when the exercise started, that would be super helpful. I can’t tell the exercise beginning time from the images. :man_shrugging:

I gotta ask you to do something for me. Trust fall, okay?

I know the CGM is accurate for you and all, but… CGM’s always have a little bit of a lag.

This will help me out a lot.

Do a BG test 15-20 minutes before you start, and then do one right when you start.

Those 2 tests will give us really good data on both the direction you were headed before you started, and what you were exactly when you started.

The next thing I want to ask you to try is just a very broad brushstroke. Not looking for any kind of solution yet, just want to get some consistent results and see what would be worth trying next.

So a lot of the changes you are making, like 33% or 40% or 50%, etc. Those might be perfect numbers to use. But it’s hard to tell exactly what you need. So we want to just start with some very consistent formulas to begin with, and then look at what happens.

So this would just be a starting point, and then let’s adjust it, depending on what we see.

  • Turn off basal - totally zero - 30 minutes before you start. Leave it off for the entire exercise. No CIQ or any percentages, just a nice easy zero basal (ZB).

On your BG checks right when you start (and also considering the one you did 15-20 minutes prior):

  • If your BG is 100-120 and relatively flat, take 20 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is 100-120 and dropping, take 35 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is 100-120 and rising, take 15 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is less than 100 and relatively flat, take 30 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is less than 100 and dropping, take 40 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is less than 100 and rising, take 20 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is 120-150 and relatively flat, take 15 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is 120-150 and dropping, take 25 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is 120-150 and rising, take 10 grams of rapid carbs right when you start, then test again after 1 mile.

  • If your BG is greater than 150, don’t take anything, then test again after 1 mile.

(On all of those :arrow_up:, dropping does not mean plummeting. If you are plummeting right when you start, either take 50% more carbs, or call it in and try again another day. Whatever you feel safest doing.)

So, none of this necessarily fixes anything. But even if you have bad numbers on a particular day, let’s make the goal to just learn a little more about Allison and her metabolism.

And if we have some good solid metrics and came away from the day with some knowledge, we count that as a positive. And we keep going. After a few more tries we adjust and then do it all over again.


I didn’t know you were unfamiliar with the Tandem interface - sorry about that! The vertical red lines are when the basal is completely shut off - so ControlIQ determined that I was dropping too fast and delivered 0 units for that time frame when you see the lines.

Yes, the clock time on the top matches up with the most recent CGM reading - so I was at 95 :arrow_lower_right: at 9:11am. In the picture you attached, it shows the most recent 3 hours of data. So the hash marks along the bottom are every hour. So the first mark is around 7:11am, and the second would be around 8:11am. On that day I started exercising around 8:27, so probably around where the pink line is (where the basal shut off):

No problem checking with my meter - I’ll bring it along with me. My training plan has me at 3.5 miles for tomorrow, so I’ll do the zero basal for 30 minutes and during the run, and try out your formula for carbing ahead of time. I usually am nice and steady overnight with no crazy boluses (as long as I don’t eat a ton of junk late at night) so that helps with starting consistently in the mornings. I will report back tomorrow with how it goes! I know I just need a little more consistency to figure out the overall pattern.

Thank you so much for all of your time and thoughts :smiley:

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Ah, super helpful to know! Thanks!

Also, there is something really cool that @needlesandmath has! :grinning: Maybe he can tell you about it!

I think you should get one too! But we can get there, no rush.

Awesome! Have fun. Enjoy it and don’t stress about any of this stuff. We learn a little bit every day.

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Wow - this is like magic. I ran 3.5 miles today without an issue! :tada: :tada: :tada:

I know it’s only the first time… and my husband told me not to get too excited yet, as the wind will change and the next time it may not work the same way.

Here is what happened:

  • 7:19: zero basal, CIQ off. spent too much time trying to find my fanny pack to carry my stuff
  • 7:57: 108 meter; 116 cgm. ate 18g chewy bar (I didn’t want to try to eat 20g of glucose tabs :face_vomiting:)
  • 8:01: warmup walk
  • 8:07: start run
  • Mile 1 (10:30 minutes): 106 meter; 124 cgm
  • Mile 2 (20:46 minutes): 100 meter; 117 cgm
  • End (37 minutes): 113 meter; 103 cgm
  • 8:45 cool down walk, ate 1 glucose tab, pump back on in sleep mode

I went a little high after breakfast but it came back down quickly. Had a huge lunch (at a special event) and it stayed nice and even. (Green lines indicate start and finish times of the run.)

So - what next?? I guess I just try this same thing again for my next run? This is the training plan I am following (the beginner one). Currently on Saturday of week 3.

I am so much more optimistic now!


@allison I use something Sam’s club sells called The Better Nut Bar before longer bike rides. Like your Chewy Bars they are A mix of carbs, protein and fat.

My BG will rise over 30-40 minutes sometimes as high as 140. Then slowly decline to the 90s when I finish at 120-140 minutes.

Sometimes I eat a second one at the halfway mark. These bars are only 9g carbs

We need to be able to adapt as today’s run, ride or swim might not be the same tomorrow. It would be nice if it was simple math.


After exercising with diabetes for over 20 years, I completely understand. It gets very frustrating trying to find patterns; what works vs what doesn’t. But with today’s tech it’s much more doable than when I was little!


@allison, congrats! This is awesome!


I was going to get into some of the specifics and different carb things and a few scenarios and whatnot. But actually I think you should just take a little time to celebrate it before we start dissecting everything.

Just enjoy it for a little bit. I will be back with some of the breakdown later.

Based on the training plan, it looks like Sunday is either cross-training or easy recovery run, right? Next big run is Tuesday?

So there are a few days to just enjoy your success.

I want to leave you with this thought though…

Yes, of course. There is no guarantee that the next time will be the same. But that does not matter.

There are only 2 things you will ever need to be successful. And I don’t mean just in running. I mean in absolutely anything you want to do.

For whatever you want to do, you only need 2 things. The faith to believe it is possible, and the will to try.

You have already shown you have the will to try. And today you got a taste of the faith. And we are going to build that.


Yes, just going to the gym for some strength training tomorrow. Back to running on Tuesday! Thanks for your support!


@allison, I wanted to go over a few of the things from your run.

The numbers worked out great! The carb recommendations were somewhat aggressive because you often had issues dropping during runs. The goal was to keep you from tanking during the run.

But another, and more conservative approach, would be to be less aggressive with the carbs right at the beginning. And instead, rely on more frequent testing during the run.

As an example, with the more conservative approach, suppose you start at 90 but you take less carbs. That’s okay, because you test a mile later. If you are 100, you are not too worried, you might take a few carbs. If you are 120, you don’t need to take anything. If you are 80, you take more carbs than just a few.

The point is, if you are able to test while running, you can be more conservative with the carbs at the beginning, and you are able to address impending lows sooner than you would see them with the CGM.

So if you want to do this, I can get you hooked up like @needlesandmath.

I want to recommend a few things that are easier than 20g of g-tabs!

The chewy bar worked great for you this time. That is a slower carb. So you got some extended carbs that lasted a little longer for you. That can be very helpful.

But there are times when you need a faster carb. It is not just the amount of carbs, but the speed. I used a variety of different things that work at different rates.

I am a big fan of the Huma Gels. They have different flavors. You can probably find one you like. My favorite is the apple/cinnamon. It’s basically like a sweeter version of apple sauce. they also have chocolate, different berry types, etc.

What makes Huma very good is the fact they use the right ratio of glucose and fructose. The ideal ratio for absorption, which is 2:1.

I suggest you try a few and see if there is one you like. This is a very fast carb, and easier to process than most gels:

Check them out here (also available on Amazon):

As @needlesandmath has mentioned using, Transcend gels are super fast. They are straight glucose. 15 grams. These will pull you out of a ditch in a hurry!
(These are also available on Amazon.)

Once you get more comfortable with all of this, I suggest hitting a bolus about a mile before you finish! This will help prevent that spike afterwards.

And I also recommend some carbs right after you finish, along with insulin. This will help prevent lows later in the day. Especially when your mileage increases.

One other note, on Tuesday, since it is a shorter run, you can probably be less aggressive with the carbs before you start.

Good luck and have fun!


If I added 15g of sucrose (1/2 glucose and fructose to 15 g of glucose syrup in my homemade mixture would that get this ideal ratio?

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Since table sugar (or sucrose) is 50-50, 15 grams of that would be:

  • 7.5 grams of glucose
  • 7.5 grams of fructose

Then adding the 15 grams of glucose gives you a total of:

  • 22.5 glucose (7.5 grams from the sugar and 15 grams from the glucose)
  • 7.5 fructose

So that is actually a 3:1 ratio.

It’s fine. It is a pretty good mix.

But the reason the 2:1 ratio is often sited as ideal is because it allows different transporters to be used in the body. So this is referenced as the most efficient and ideal mix.

But as Dr. Asker Jeukendrup says, there is not a magic ratio. You can have slightly different ratios and it still works.

Dr. Jeukendrup is an authority on this subject. Here is a good link to the subject:

That’s what I get for just writing off the top of my head and not doing a little work - yes that would be 75% glucose and 25% fructose. DUH! To get 30 grams with a 2:1 ratio would be 10g glucose with 20 g sucrose, I think⁉️

My Mom (rip) would be appalled at my declining math skills.

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One day delay - didn’t get a good night of sleep Monday morning so slept in on Tuesday, which was day 8 of my sensor… the sensor went all wonky so I took it out at work and didn’t have one to replace it right away (but did have my meter); I forgot to bolus for lunch thanks to being low… you know, after almost 30 years of this you’d think I would know what I’m doing. So - needless to say, I didn’t run yesterday!

But - this morning I did a successful 3 miles :running_woman:!
(I didn’t take my meter with me this time so these values are from my CGM.)

  • 8:23 zero basal; CIQ off - 137 on CGM
  • 8:50 chewy bar (18g) - 123 on CGM; 128 on meter
  • 9:00 warm up walk - 126 on CGM
  • 9:13 run 3 miles - 144 at start
    • mile 1 - 178
    • mile 2 - 176
    • mile 3 - 164
  • 9:45 cool down walk - pump reattached; took some boluses starting at 9:50 for high coverage and pending breakfast


So, I didn’t use your exact pre-carbing formula - probably should have had fewer grams, but it worked out ok for the distance today!

Forgot to address the gels thing - I have some old Honey Stingers and my coworker gave me some Ucan gels to try. I am not opposed to using them and can afford them, but holy cow - $2 for one serving seems nuts!


Good job today!

Was your basal off too?

A little bit spiky, but that’s okay. It’s a good checkpoint to see what carbs you need. It seems like you can be more conservative with the carbs when you are above 120.

There is usually a bit of a drop in the first mile or so, and you did not see that today, so it was definitely a bit much.

But I do see the drop between miles 2 and 3. Was any insulin involved, or was that just your body using up the glucose? If there was no insulin involved, that’s a good thing to remember for how your body responds to that distance and pace. Like if your BG is around 100 at mile 2, you would want to take some carbs!

There are a lot of things you can use. I just like the convenience of the gels. Pre-wrapped, easy to carry, and known quantities and so forth. They are super easy to use while running.

So a good solution might be to use other things before the run, and save the gels for during the run.

Or just completely go with something else altogether. But try to find something that is easy to carry, easy to open while running, and easy to eat while running. (Big plus for the gels on all of those. There isn’t really anything magic about the gels, they are just easy.)

Just don’t do anything that is hard, like hard candy. That’s dangerous when running.


Just want to say I love these threads,I am in the early stages of building my exercise back up, so am on the side lines taking notes, as well as rereading some older posts.