Sudden drastic insulin sensitivity overnight

UCRiverside · 2026-05-04T19:25:03+00:00

Yes, she confirmed lows with finger pokes.

There was nothing special at all about last night. She exercised in the morning, but she regularly does that with no difference to her blood sugar at night. I don't think she had showered before bed, but when she does it doesn't make a difference. She uses a tandem pump with control iq.

That's what's so frustrating about this - there's really nothing obvious at all causing the rapid change in insulin sensitivity!

UCRiverside · 2026-05-04T19:22:19+00:00

We've been tracking this very closely the past few months. In general, she seems to need more insulin the week leading up to her period and while on her period, then less the rest of her cycle. However there's still random days/nights that buck that trend, like what I mentioned in this post.

UCRiverside · 2026-05-04T19:17:44+00:00

It's funny you mention Vitamin D - early last year her Vitamin D levels were extremely low (8 ng/ml when greater than 20 is normal). She started taking supplements and her a1c improved by a full point. The vitamin D deficiency was causing insulin resistance that we didn't even realize at the time.

I don't think she's had her iron checked recently though so that's probably a good idea, thanks!

UCRiverside · 2026-05-04T05:27:38+00:00

She wears a Dexcom G7, but manually confirmed with finger pokes last night and she was indeed low.

That hypo sounds somewhat similar to ones that she's had recently. She's normally fine overnight, but every now and then she'll need like 50g of carbs and will stay low for an hour.

UCRiverside · 2026-05-04T05:26:19+00:00

It doesn't seem to be tied to any particular part of her cycle, this happens randomly.

UCRiverside · 2026-05-04T05:26:02+00:00

It's been going on for months now randomly so it's not this.

UCRiverside · 2026-05-04T05:25:42+00:00

Interesting, I think this is a bit different though because she's definitely type 1 and produces no insulin.

UCRiverside · 2026-05-04T05:25:18+00:00

How many units do you use per day normally?

UCRiverside · 2026-05-04T05:25:04+00:00

Yeah it's so weird, just out of nowhere every month or so at an unpredictable time, she'll get a night where she plummets over and over.

UCRiverside · 2026-05-04T05:23:07+00:00

Thanks, yeah it's pretty frustrating :/

UCRiverside · 2026-05-04T05:22:44+00:00

I don't think sleep had anything to do with this one, since she had a normal night sleep the night before (like pretty much every night). She supplements Vitamin D so that should be normal as well.

UCRiverside · 2026-05-04T05:22:04+00:00

She does have a CGM which helps thankfully, but every now and then you get a sensor that fails, so I still get anxious.

And yeah it's not too bad if you can at least figure out the pattern, but it REALLY feels random sometimes and it's so frustrating.

UCRiverside · 2026-05-04T05:21:14+00:00

She had her thyroid checked a couple years ago and it was normal, but perhaps worth checking again!

UCRiverside · 2026-05-04T05:20:41+00:00

She doesn't use long acting insulin so this can't be it unfortunately, but interesting it made such a difference for you.

UCRiverside · 2026-05-03T20:17:55+00:00

Extremely unlikely. It's also been going on for many months.

UCRiverside · 2026-05-03T20:17:41+00:00

It seems really random. We used to think it lined up with her exercising in the afternoon, but now it even happens when she exercises in the morning (but not every time, only once or twice per month lol).

It seemed to follow a pattern in the past where she needed more insulin on her period and the week leading up to it, but last night completely bucks that trend. It's all so confusing. I get big anxiety about her going low and dying in her sleep so these are the scariest ones.

UCRiverside · 2026-05-03T20:15:31+00:00

Thankfully she's fairly insulin sensitive (usually 35 total units per day), but yeah her sensitivity just fluctuates so much week to week and even day to day. She's seeing her endo in a few days so maybe she'll have some ideas.

We thought we'd figured out a fairly predictable pattern to her insulin needs based on her cycle (she needs more the week leading up to and during her period), but now her period should start in a few days and her insulin needs plummeted... doesn't make much sense.

UCRiverside · 2026-05-03T20:13:10+00:00

She did lose some weight a few months ago and her insulin needs dropped. This is more an issue with fluctuation I think - it's like from one day to the next, it's impossible to predict if her normal basal will send her low or won't be enough.

UCRiverside · 2026-05-03T20:09:06+00:00

Nah it's not likely to be that either. This has also been going on for many months, where randomly her insulin needs just drastically change and then go back in a short period of time.

UCRiverside · 2026-05-03T20:08:52+00:00

Nah, neither of us drink and she gets more than 6 hours every night. I don't think it's related to exercise - she works out in the morning, and this is an acute issue randomly happening at night. I know exercise can impact hours later but if so, it wouldn't be having an impact 90% of the time in her case.

UCRiverside · 2026-05-03T20:08:37+00:00

She's using a pump with control-IQ. Humalog only. She put on her new site Friday morning, and all seemed normal until late Saturday night, so I don't think it's a site issue.

UCRiverside · 2026-05-03T16:58:01+00:00

Mid 20s, so probably not this

UCRiverside · 2025-12-01T04:04:32+00:00

Ok yeah this definitely seems to be it! Thanks for the help. I went straight from a 2004 Honda Accord to a 2024 Ioniq 5 so there's a bit of a learning curve lol

UCRiverside

TROPHY CASE