Unexpected night low

Last night we had a deep, unexpected night low.

After coming home from school, my son asked to have an early dinner with a friend at Culver’s, a Midwestern burger joint, and we agreed. He took his bike for a short 20 minute ride there, had dinner, came back, then spent the evening working before going to bed.

Around midnight he started going down on the Dexcom, at a moderate rate. I gave him some milk with a straw so he would not have to wake up. 20 minutes later, he was still going down at the same clip, when I had expected to see a flattening trend (the Dexcom sensor is about 15 minutes behind on carb intake for us).

So I hand tested him. He was at 27. I gave him a bunch of extra fast carbs, tested him again 8 minutes later—he was still at 38. It took a good 2+ hours to bring him back to am even keel.

The event itself is no big deal, although we don’t see 27 often. What was shocking was that we were not expecting any low that evening based on activity pattern: my son typically bikes for 30-45 minutes every evening when he does not have a practice, so his bike ride was not something we we were worried about.

In the end, we think that, because he was biking in freezing temperatures, his bike ride may have had a very different glucose consumption profile, and his heavy carb dinner was not enough to refuel him. That the the only explanation we can come up with.

The lesson we are drawing from this is that, for a teen, bad lows can occur at any time without any expectation. It is a good thing we had a running Dexcom.


@Michel personally, I think your theory regarding exercising in the cold has weight. Every time I excise in colder than normal (read freezing my a** off) weather I have persistent lows that are very hard to resolve. Went for a walk once in West Seattle in dead of winter and almost had a major hypo event that took several hours to shake (needed professional help on that one). Guess I am no longer Buffalo acclimated and now used to sometimes sunny Calif weather.


I have seen similar nighttime persistent lows (a handful of times) and was not able to deduce the reason. Without having it happen a number of times with similar daytime activities then IMHO it is only grasping at straws. I just deal with the issue at hand and don’t overthink the “why” of it. If it happened more often than it would both be more important to understand as well as have enough “data” to really figure out a cause.

[EDIT] Part of this post was moved to How do you treat a bad low at night?


Unexpected bad lows can happen for no reason for anyone with Type 1, adults included. That’s what makes the Dexcom so incredibly valuable. I’ve had overnight lows lasting hours (with repeated treatments) with no explanation. Glad you caught it in time!

[EDIT] Part of this post was moved to How do you treat a bad low at night?


6 posts were merged into an existing topic: How do you treat a bad low at night?

Shivering does expend energy and burns calories, so depending on how cold he was it could be a factor. But there are a lot of other factors that are probably bigger contributors.

I am guessing you were not expecting it to be a significant drop since you were using milk.


What was the Dexcom reading and delta at the time you tested him with a BG of 27?

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The CGM measurement before the fingerpoke was 53, the one after was 48. A big discrepancy!

That is right. He was in the mid 70s going down about 1 per minute when I gave him the milk. I was taken aback by the 27 reading, enough that I measured it again after 8 minutes. It was still 38, after ingesting a bunch of fast carbs about 8 minutes ago, so the 27 must have been a reasonably good number.

@elver, this is really interesting feedback. I did not realize that the cold could cause such a difference.

I am still puzzled as to why.

I am with you on this. I do think of possible causes when it occurs so as to correlate them with future possible incidents: I find it facilitates the debugging of future problems. But I don’t make it a big issue. My main point in the post was the fact that these things may happen without our expecting them.

Again, I am glad we had the Dexcom. It could have been a nasty event if this had been a no-Dexcom day.

@Thomas, @Jen, I split the thread and moved part of your posts to How do you treat a bad low at night?, hope it’s OK!

I too have had unexpected issues in the cold, both from my transmitter and unexpected lows.This past winter has been much colder in this area than last winter. This is only my second Jan-present wearing a Dexcom transmitter. I wear them on my upper thigh a lot, but was finding that working at the farm on the weekends was causing dropouts in my signal, even through a layer of heavy long johns and heavy sweats. I moved it to my upper arm and stopped having the issues when I was outside. More layers and warmer on the top half of me. But I also noticed when we were doing that work I was experiencing more lows than when doing the same sort of work over the summer. I’m sure there could be other reasons, but I’m blaming the cold.


Well, I think this calls for an experiment. I am sure you won’t have any issues moving to the arctic circle for a year to test out our hypothesis…