Fixing the Low to High Rollercoaster

I’ve been reading Think Like a Pancreas and realized it’s not normal to go low multiple times a day, every day… :sweat_smile: Haha. We convince ourselves of silly things, huh? (Still only 20% of the way through, so I’m sure I’ll learn more good things!)

I’m stoked for my next endo appointment. CGM data is changing my life!! My brain was like, “yeah, I don’t go low that often”… I was wrong. I just didn’t always check, because I can almost always feel my lows. A really bad habit that left me with no solid record. How much can my endo help me without info? :woman_shrugging: I’m excited to discuss possible pump basal issues with her.

In the meantime, I still need to fix my approach to lows.

My brain feels lows intensely and hates it. I feel like I’m dying every time, even though I know from experience that I will be fine. As a result, I often overtreat… putting me on the low / high / low / high rollercoaster.

Here’s how I’m working to improve so far. Other tips are always appreciated!

  • Treat early. Avoid lows if possible.
    • For example, treat a CGM downward trend at 100 instead of at 70.
  • Treat small. Eat 5-10 g. at a time. I can always eat more if needed.
    • This amount may not apply to severe lows or to different bodies. Play it safe, just avoid devouring everything in sight for no reason.
  • Test often. The CGM lags 5-10 minutes.
    • My CGM may still show BG dropping. My brain might still feel like it’s “dying,” because glucose takes time to get into body tissues (thus the CGM lag). But a test might confirm that my BG is stabilizing or rising.
  • Be patient. Carbs may be faster than insulin, but they still take time.
    • It’s hardest to be patient when I’m going low and need to drive to work, to an appointment, etc. But more carbs doesn’t necessarily mean I’ll rise faster, just that I’ll rise more.
    • Set a timer if needed. Today I set a 5 minute timer when I had already treated small once. I told my “dying” brain that if I still felt so bad when it went off, I could check and treat small again. By the time it went off, I felt fine, and my blood sugar was rising. Rollercoaster avoided!

All the stuff you are saying sounds like a good plan! A very good way to approach it all and to avoid the rollercoaster. :+1:

But I wanted to perhaps put some fears to rest about your brain, because you said that your brain hates low BG. I can understand the feeling.

But your brain is okay! Your brain keeps getting glucose long after everything else is shut off.

The body is cleverly designed. The brain uses the GLUT3 glucose transport. Since GLUT3 is a high-affinity glucose transporter, only a small amount of glucose is needed to saturate it.

Even though you feel it, and you lose some cognitive function, the brain can keep getting glucose until you get to the danger point of below 40. That’s when the glucose is no longer able to get into the brain at the normal rate.

Here is a page from Biochemistry, 5th Edition (Section 30.2):

Keep doing what you are doing! All of this is simply to say - avoid the super-low BG’s, and you are okay. :ok_hand:


Fascinating stuff! Thank you! My steady brain appreciates all the knowledge (even if my low brain takes some extra convincing).


This one has been helpful for me - and only made possible by the CGM.

The one that’s not on your list that you might consider: don’t over control - you can raise your BG target. Running a little bit high is better than having a daily low, according to my endo’s. So my bolus decisions are biased down (if i think i should bolus 5 or 6, I’ll go with 5). I might run at 120-130 blood glucose (US measures) but I won’t go low during the day.


Thank you! This is a great reminder. I do tend to get frustrated when I go high, and that puts me in the high to low side of the rollercoaster… And that can be needlessly stressful.


Or: Treat big, and take some insulin. Seems counter-intuitive, but it works 9 times out of 10 for me. If I’m having a serious low or a series of lows, my “crash cart” item is a Cadbury’s Creme Egg. I inject for 25 g carb. No roller-coaster.


That is so counterintuitive – but it’s good to know! I think I can see how it works… like a delayed meal bolus sort of, instead of pre-bolusing? The treatment carbs will still hit my BG before the insulin kicks in, and the bolus would keep the BG from spiking so high so fast once it’s moving.

I’ve accidentally been doing that this week when my brain just can’t resist the urge to treat big :joy: It’s nice to really think through the method to the madness!


The last week using this low strategy has gone well! I’ve only had one rebound high! :partying_face:

I’ve still had just as many lows, even with no bolus IOB, but the roller coaster isn’t as high and low. I’m 40% into Think Like a Pancreas and slowly trying out basal rate tests.

Wised up and turned off Control IQ (duh!). With my basal rates obviously not being right, it was just worsening the problem. Control IQ would see a “fast rise” from a low treatment and automatically bolus a correction… instead of waiting to see my BG leveling out at 120-130 a couple minutes later, then slowly heading down again. The auto correction was just adding fuel to the next low instead of preventing the spike it was expecting.

Progress, day by day!


I love cradbury crème eggs. Easter went by so quickly I missed them. Whine!!!


@RachelMaraii I think your approach is pretty great! I do similarly, though while I’ve set a mental timer, I’ve not actually set one on my watch and might try that. When treating a low, I do incorporate checking the IOB and sometimes suspend any additional insulin for .5-1 hour in addition to taking 1/2 or 1 or 2 tabs worth (2, 4, or 8 carbs) depending on how fast it seems to be moving down; while I think Loop does that anyway based on projected BG, it at least makes me “think” I’ve done something. What I really dislike is going high following a treatment because i “missed by THAT much!” (Got to love Get Smart!) :joy: