Managing your blood sugar levels with unplanned exercise

I log into work around 4:30 am. I have an eliptical and a bicycle in my office. If there are no emergencies at work I like to jump on one of them for 10-15 minutes, and hopefully I can do that several times during the day. The problem is that my sugar is between 100-130 at that time of the morning. So if the exercise is unplanned then my sugar level drops. I don’t have time to exercise in the afternoon or evenings so that is why they are in my office so that I can take advantage of slow times at work. Is there any way to keep my sugar at a good level during this time. I usually end up going low and then having to handle it.


Do you use insulin pump or pen/syringes ? Or oral meds?


Pop a few carbs🍭. Quick action to cover unplanned exercise.


I use an insulin pump. I reduce my basal when I am outside riding my bicycle but that is a planned activity. Reducing my basal 2 minutes before I exercise doesn’t seem to work. This morning I did down a cup of juice right before I rode. It helped that I didn’t bottom out but now I am at 51 so will have to eat/drink something. I was at 136 when I started to ride.


Hi @HippieNerdBabe

A basal reduction right before you start can be helpful for keeping your BG from tanking if the exercise is longer, but also it can help after the exercise is finished. You become more insulin sensitive, so keeping it reduced after you finish can help prevent the lows that follow the exercise.

As an example, right before you start you may do a 50% reduction for an hour, even though the exercise is only 15 minutes.

Since these are short segments, 10 or 15 minutes or so, tell me when you drop. At some point after the exercise, right? For longer durations of exercise, dropping during the exercise is normal. But for shorter ones like 10-15 minutes, the drop would generally be afterwards,

Do you eat breakfast in the morning? Can you tell me about that?

Is your goal more fitness oriented, or for weight loss? If it is more for fitness, then taking carbs to prevent the BG drop is good. But for weight loss, taking carbs somewhat defeats the purpose (not entirely, because the exercise does help your metabolism, so the exercise is still helpful, but taking in the extra carbs is just not ideal if your goal is for weight loss). So the best solution depends a little bit on your goals for exercise.


Yes, you are correct. I am dropping after exercise. I will try your recommendation about dropping my basal for an hour. I get up around 4:15 am and start working between 4:30 am - 5:00 am. I live on the West Coast but am still working East Coast hours. So I try to fit in the exercise anywhere from 4:30 am to 7:00 am. I eat usually between 7:00 - 8:00 am. 95% of the time it is oatmeal. And my goal is fitness oriented however I would prefer not to eat just so I can exercise. There has to be a happy medium (??). I manage much better with planned exercise like in the summer when I take a long lunch and go for a bike ride. Sometimes that backfires on me when I’ve eaten a Clif bar and reduced my basal and then get called into a meeting. But thankfully that doesn’t happen very often. This time of year I am very busy at work so trying to plan exercise during the day doesn’t work. Working 12-14 hours is normal.


Generally speaking exercise drops your BG because 1) your body is burning up glucose to fuel the exercise, 2) your body becomes more insulin sensitive, and 3) your insulin is getting absorbed faster as your blood moves faster in your body and your body heats up.

So the easy options are to either reduce basal, which takes a little time, or take in carbs.

But for issues with not wanting to take in EXTRA carbs, the other possibilities are:

  1. Possibly timing your exercise so you can have more time to reduce basal before

  2. Timing your exercise so you can eat a meal afterwards (you are going to eat lunch anyway at some point, so that would not be “extra”)

  3. Timing your exercise so that it is right after breakfast. (Possibly delaying your breakfast until right before exercise. Since you eat breakfast anyway, that is not “extra” carbs.)

  4. Or…micro-dosing of glucagon!

Does all of that make sense?


before I surf I suspend my basal 1 hour prior and resuspend it right before I paddle out as it can only be suspended for two hours, sometimes i am in the water that long. I try to get my BG above 200 before I go out. Eat a ‘Kind Bar’ (18g carbs) because it is nut based and the carbs will last longer. After an hour I take a break and check my sugar. Usually BG is 100ish so I eat another bar and slam a juice box(30g carbs) gets me right back yup quick and after hour two I am back around 100. THis is obviously planned exercise. I went low on the water one time and it was pretty darn scary.
If I decide top just hop on the bike and take a ride that will be more than a couple of miles then I suspend bolus and eat a ‘Kind Bar’.

I would always prefer to misjudge on the high side than go low while exercising.

I am new at all this but have found this method has been working for me…hope it helps



Hi @jeffsurfsncocktails
A couple things to mention. If you already know this, please forgive me for mentioning it!

Since you said it can only be suspended for 2 hours, that means you are doing a suspension instead of a zero temp basal. Let me explain the difference, because it is very important to understand!

  • If you select suspend, the pod will beep at the end of the suspension, but even after the suspension time is over it will not return to delivering basal - until you manually turn the suspension off. The time thing on a suspension is only the time before you are alerted. That pod will actually remain at zero delivery forever, until you turn the suspension off! So basically, there is no 2 hour limit there, it is only 2 hours before you get aggravated by the beep.

  • Re-stating this, because it is a big deal - The time on a suspension is NOT the time before insulin delivery returns, it is only the time before it starts alerting you to turn the thing back on!!

  • Suspensions are a bit dangerous because it will NOT return to delivering basal unless you manually turn it back on. And the time thing is very misleading. I have no idea why Insulet did this! :roll_eyes: A suspension remains, until you turn it off, regardless of the time you put in there. That was a bad call by Insulet.

  • Instead, if you create a zero temp basal, you can turn basal delivery off for any 30 minute increment, from 30 minutes to 12 hours. And after the zero basal time is up, the pod WILL return to delivering insulin.

So in your scenario, suppose you set a zero temp basal for something like 4 hours. After you get out of the water you can turn the zero temp basal off, and basal delivery returns. If you forget to turn it off, after 4 hours it will return to the normal basal delivery by itself. Even if you lose your PDM or it gets wet and destroyed, the pod will return to normal basal delivery after 4 hours! And it won’t beep the whole time.

On the other hand, if you do a 2 hour suspension, the pod will start beeping after 2 hours and annoy you while you are surfing. And if your PDM gets lost or destroyed, that pod will never return to delivering insulin.

Anyway, the zero temp basals are the way to go with that.

Suspension vs. Zero Temp Basal

If you don’t have access to your PDM, you are screwed with the suspension.

The only time I use suspension is when I have to change the clock on my PDM, because that is required. I suspend, change the time, and turn it right back on. Other than that, I always use the zero temp basal instead.


@Eric that makes perfect sense and I had no idea!!! I do use the beep ti let me know I have been out for about an hour and need to take a break. But now I know I do not need to reset it. Thank you for the info!!!


@Eric Thanks for the info on this. I recall hearing/reading about “temp basal” vice “suspended” was the way to go, but didn’t clearly understand the rationale as you explained and hadn’t read that portion of the book/manual as yet. I’m getting ready to do some traveling so thanks to @jeffsurfsncocktails and you for the discussion.

Question: I’ll research in the manual/other sources, but sounds like you have practical experience. So, if you don’t suspend before resetting the time on the Omnipod PDM, what happens?


It won’t let you change time or date without suspending!

You have to suspend, change the date/time, and then un-suspend. No other option.

So a short description so everyone knows.

On the OmniPod PDM - a suspend will never resume insulin delivery until you MANUALLY end the suspension and resume. Even if you say suspend for 30 minutes, after that 30 minutes is up, it won’t actually resume until you manually end the suspension. It will beep at you, but won’t ever turn insulin delivery back on by itself! This is a pretty bad option for anything other than changing date/time.

A temporary basal of zero will give you no insulin during that time, but will resume BY ITSELF when the time ends. Even if you do not have the PDM with you, the temp basal will end when the time ends, and normal insulin delivery will return.

All make sense?

So basically, suspend should only be used when changing the date/time.

(Or if you want to edit the basal profile you are currently using. But instead for that, you could switch to a different basal profile, edit the one you want to edit, and then switch back. So edits of your basal profile can be done without suspend!)

For everything else, use a temp basal.


@Eric Thanks for the patient and comprehensive response for us newbies!


it may not be necessary to have exercise machines, you can do exercises in the office, for example, with fitness elastic bands


So true, several times I’ve just walked up and down the stairs at our cabin in WV when its raining out and I’m high. The exercise usually helps a stubborn rise in BG when the insulin seems ineffective…


Running around causes Liam to go low.

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I see that at least 2 years ago you were using a Dexcom, so that means you have an indication of your BG during exercise. I am type 2 on a T:Slim pump with Dexcom who exercises daily.

I often do a bike ride, stationary or on the road every morning 30 to 60 minutes. I see quite a fast drop when using the stationary, but will see a drop after 40 minutes on the road bike. My first suggestion is to do a finger stick to check that the low is correct. There may be a loss of interstitial fluid due to a bit of dehydration.

I have a 5 OZ plastic bottle with a bite valve filled with 1 to 1.5 OZ of glucose syrup, strong coffee and the contents of a coupe of electrolyte capsules. With 1 OZ glucose an OZ of this is 6g carb. It is cheap and effective. The strong coffee cuts the cloying sweetness of the glucose.

One of the things I found, if I have a BG of 65mg/dl at the end of a ride and do not consume any additional carbs, my BG will tend to rise on its own. This is why I started doing a finger stick. I found that sometimes at 65, I tested in the 90s. Oh and at a reading of 65mg/dl I am not having hypo symptoms, which is why I started checking.

BTW - It is good that you are able to get some regular exercise. I firmly believe that it is as much medicine as any pill or injection.


Carlos, am I understanding you correctly in that your plastic bottle has a combination of glucose syrup, coffee and electrolyte capsules all mixed together? Sounds interesting. I always hate to have to stop my bike (either stationary or on the road) and rip open glucose packs to treat a low. I did repurpose a pouch that you are supposed to attach to your shoelaces to carry your driver’s license, etc. and fastened it onto the frame of my outside bike in front of me. A tube of glucose tablets fits nicely in it and sometimes I can just reach down and grab them without stopping my bike. I like the idea of the liquid though.

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What’s not to love, a diabetic bicyclist who calls herself HippieNerdBabe?
Yes, I use a 5 OZ flask from Hammer nutrition. The glucose syrup is Karo corn syrup that has no HFCS. It has no color like the regular Lite Karo. One OZ equals 30grams. Using I OZ of syrup makes each OZ of the mixture 6g, with 30g for the whole thing. If 1.5 OZ is used then each OZ is 9g with 45g in total.

There is no reason to use coffee. I do that because it cuts the cloying taste of the syrup. The electrolyte caps don’t add much electrolytes unless all is consumed. I cut the end off with a razor knife.

In the picture you will see a jar of instant espresso coffee. I add a 1/4 teaspoon to the coffee in the flask. Like I said you can make it up with water or maybe PowerAde Zero. A tip, whatever you use to dilute the syrup needs to be warmed a bit to ease mixing.

I came up with a way to stick the flask on my top tube with magnets and Velcro. This is not working well so I am carrying the flask in my back jersey pocket. The flask is $2.39


Something I noticed with the drop in temperature. The Dexcom and finger sticks are damn close no. That might be a point in favor of my thinking that a slight dehydration of the interstitial fluid from sweating can cause CGMs to read low when BG is not low.

On this morning’s ride the temperature was 63° to 79° F. Somewhere in the middle of that Dexcom was reporting 74mg/dl and I did a finger stick for 70mg/dl.

During the summer and beginning of September rides is when I would get the discrepancies.

I just found the following:

You have this thing called interstitial fluid that’s keeping all your organs damp and moist. And that liquid is sourced from blood. And when your body gets the cool-down directive, then your sweat glands source sweat from that interstitial fluid.
Sweat Is An Evolutionary Marvel Allowing Humans To Survive And Thrive : Shots - Health News : NPR

So maybe I am not all wet - pun certainly intended. HAW