Longish-term decrease in TDD?

For at least two months now, Samson has been having really really rotten lows throughout the day. I wish I could say we were very prompt in addressing the underlying problem (John Walsh of “Pumping Insulin” fame says that you should circle every.single.low and try to identify a cause before doing anything else), but alas, life and a new baby, plus Internet problems meant I wasn’t doing the normal data analysis I usually do.

Well, I finally got around to looking at this stats, and it turned out his TDD had dropped from about 11 units per day to 6 - 7 units per day over the past months. His total basal rate, programmed as the baseline in his pump, was around 6 units!

That’s a huge difference! So even though openAPS was zero temping him throughout the day, it still couldn’t catch up to how often he was going low.

Anyways, we decreased his baseline basal rate to about 4 units and have not seen the same nasty lows.

But I’m wondering: What can cause a steep drop in his TDD? He’s not eating fewer carbs. (If anything, his diet has become total c*** lately because we’ve just given into his carbaholic tendencies and let him eat things like pizza, english muffins and Halloween candy all day long without insisting on him eating more fruits and veggies). Plus it’s holiday season – so for instance this morning he ate half of his oatmeal and then juice, bagel and cupcakes at his brother’s holiday party. Really, really not a healthy diet right now.

He’s not exercising more. (In fact he’s stopped walking to school as we’ve moved somewhere that it’s less feasible, and swimming lessons are all booked up until February).

He doesn’t seem to have any kind of tummy troubles or disturbances. He’s not sick (or no more than is usual).

He does look a wee bit slimmer than usual, but that could be a result of using less insulin, not vice versa. And besides, he does go through slimmer and chubbier periods anyways.

Has anyone else seen a fairly stable long-term drop in TDD without any of the above changes?

I’m hoping this continues of course, but don’t know what’s caused it. I mean, in theory some of his beta cells could have briefly flicked on – but that is also a sad thought since i know his immune system will eventually find and destroy them.

I know Celiacs can sometimes cause lows, and he has been eating a lot of bread lately. But he doesn’t seem to have any other stomach complaints and seems to overall feel good. He tested negative for antibodies last year, so I’m hoping that we’re not facing that…

Any other ideas? Can cold weather make insulin more powerful? Could just growing up make his TDD lower?

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I remember stuff like that happening at times when I was very young. Possibly a bit of leftover honeymoon beta cell activity.

Activity is a huge factor. Even if he isn’t walking to school and you don’t think he’s exercising, maybe just the new baby is causing some sort of extra activity for him.

Or maybe less stress in general, just enjoying life and his new baby brother.

There are so many things that are intangible.

Very interesting. We have noticed very similar behavior. We thought maybe it was a difference in absorption from site to site–but it continued through multiple sites. The effect has essentially forced us to reduce basal rates at certain times and change his carb ratio. We were having very strange and sudden drops for no apparent reason. Even with Minimal IOB, no excessive exercise and even meals that weren’t covered with insulin at all. Although we don’t have a definite reason, my personal theory is that his body is fighting a bug (without being symptomatic) and his digestive system is not metabolizing at the same rate. I obviously have no hard data to confirm this except for the observation of my youngest has a runny nose and my wife and I are feeling sluggish.

If it was just a few weeks this is what I would have suspected too. But this is going on about two months now, which seems too long to be fighting off an infection, right?

@Thomas, that’s a good thing to watch for. Usually we worry about our older one, who is much more pint-sized (Samson is exactly the same weight as his brother who is 2 years older, and maybe an inch or two shorter). But we shouldn’t neglect the possibility that his growth is plateauing somehow.

As trends go, our changes in TDD seem to come and go. About once per month our TDD changes by 15-20% for a week then goes away. I am guessing it has some relation to growth, but some of them can be explained by sickness or stress, but not all of them.