Delayed Low After Exercise

Hey all! Does anyone else experience delayed lows with certain types of exercise? I just got done shoving carbs into my kid before bedtime to get his sugars up over 100 before bed. We went on a bike ride about 4 hours ago and it didn’t seem to affect his sugars at all at the time, but it really seems like it hit him a few hours later. What gives??? Usually when he’s exercising we stick to the 15 carbs every 30 minutes rule but didn’t really seem to need to this time around…until much later. I’m so confused. Thanks!!!

Hi @lucyinthesky827 exercise like bike riding can affect blood sugar for 48 hours. Sometimes I can have a long delayed low because I have depleted my glycogen storage during exercise. Glycogen is a type of sugar stored by your liver. When my body is making glycogen I have to eat a ton of carbs and my blood sugar stays low. It’s easier with a pump because I use temporary basal so I’m not feeding the insulin plus storing glycogen. Exercise is a great thing it’s just a little trickier with T1. Cheers. .

Hi Lucy @lucyinthesky827, like @Joe, my body glucose level will almost always drop after a bike ride - for me, the “severe” drop will occur 6 to 8 hours after riding, even if I have a large meal in between.

I use an insulin pump which makes it easier to manage BG, and before I began using control IQ - which doesn’t permit temporary basal settings - I would lower my insulin by at least 50% 90 minutes before beginning a bike-ride.

Hi @lucyinthesky827. A nutritionist can help you choose snacks with “staying power” although I don’t know if there’s a maximum time limit, as it were. You might also do some research (or again talk with your nutritionist) about the glycemic index: two foods can have the same can count for a serving, but one will cause a spike followed by a drop in blood sugar, while the other will cause a more gentle rise followed by leveling off.

It gets difficult to know what is “good” and “healthy” for your body when exercise brings on such resistant lows, and then sometimes the corresponding highs, huh? I feel for you. And, this may be a unique thing to my newly more bizarre body, yet I am hypersensitive to any, I mean any as low as 0.025 units of active insulin on board, insulin when I exercise. I will often plummet 100 points if I exercise within the 4.5 hour timeframe that my insulin stays active in me. Do you know if this is the case for you? If not, it might be worth monitoring. It leaves it difficult to find time to exercise, though. Bright and early in the morning, if no corrections are needed, seems to be the time. Good luck.

Maegan, I think I’m understanding what you are saying. In my “old age” [in seventh decade shooting insulin], I’ve become increasingly sensitive to insulin. I tweak pump basal rates by the one-hundredth [0.01] unit.

Rather than need to fix “resistant lows”, I proactively avoid them - as best I can. For instance, in non-covid times I give my time helping on 8 - 10 hour weekend days in building/rebuilding projects which often involve heavy exercise - digging, building, etc. I use a Weekend Profile/Pattern which I activate on Friday evening. This Profile has lower basal rates that become active very early morning so that I have less “free insulin” floating around in my body while working. Helps too, that my work-belt has pockets for juice-box, granola bars, and I’ve educated others about diabetes management. YES, I’ve been escorted to safe places and told - EAT!!!

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Sorta, yet different, Dennis. I am happy that you use the power of your insulin pump with varying basal programs for various activity levels in your life. My first experience with an MDI basal/rapid acting insulin regimen, my endo referred to my study days as “toad on a log” basal rates, or something like that, versus my more active walking across campus several times a day rates. Now, I too, have all different kinds of IPT basal programs for different kinds of activity days, as well as varying program rates for the female hormone fluctuations in any given month, etc. This glucose lowering severity while exercising is newer for me, and specific to active insulin on board from a bolus, irrespective of the reduced basal rates already in place. Good luck with your continued management.

I had the same issue with long (> 30 mile) bike rides. As muscles repair after exercise they use body’s available glucose. So, BG can drop. this can take place in the several hours after exercise is done. Before riding and during as needed I eat Bonk Breakers, a bar with complex carb that metabolize slower than a typical granola bar. Afterward, a protein shake or chocolate milk.

Like everything about diabetes, it’s unique to the person, It’s unique to the insulin delivery system too. Some pumps have an activity setting., like my Medtronic 670G. When I was working, an active day could hit me 24 hours later. It’s trial and error on how many tabs or protein with carbs will bring you back to normal. You might keep a log so you can track the successes.

I experienced this with my T1D son if it is an exercise or activity that is new or that he hasn’t done in a while. After his body adjusts to the new activity, it doesn’t happen so much. For example, we always seem to experience this at the beginning of soccer season. Once he gets back into the routine of playing, we may experience lows during the activity but not the delayed lows of several hours later.

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I do log. Hourly. Both sensor, and at times SMBG comparative readings with carbs, calories, and activity. It’s obnoxious not to hold on to a trend for more than 48 hours.

Ya, seasoned marathoners mentioned this to me. My plummets with IOB happen with simple in bed leg lifts for physical therapy, and a few yoga stretches that do not raise my heart rate. Congrats on cracking your code. I never tried many of the performance bars/drinks. Sounds like they work for you.