What's Really Causing Your Unexplained Blood Sugars
The pump site. The insulin. The food from six hours ago. The stress. The general vibe. Neil has blamed every single one of these for blood sugars that made no sense, and for 34 years, he kept leaving one variable off the list entirely...
The episode, word for word
OK. I said I had a number for you. Here it is.
21%.
One study. Scientists tracked people with type 1 diabetes. Researchers had them sleep either 8.5 hours or 4 hours. The group that slept 4 hours (that's not a lot of sleep, cap'n) showed a 21% reduction in insulin sensitivity the next day.
They all ate the same things, took the same insulin, did the same activities and viola.
21%.
Let's talk about that.
My name is Neil Greathouse, and this is Your Best T1D Year.
All right. Welcome back. Welcome to Week 2. I promised you a number and here it is and I want to make sure it lands properly, so let me build this out.
The study I'm referencing looked at a whole slew of people with type 1 diabetes. Now, I know this sounds like a made up study or something off of buzzfeed...but it's not.. Here's the thing: the effect was so consistent that it showed up clearly across every single participant. This wasn't a subtle trend. Every single patient. Every person in the sleep-deprived condition showed reduced insulin sensitivity the next day.
So. Let me make sure "insulin sensitivity" is landing clearly, because it's one of those phrases that sounds clinical but it's actually very basic.
Insulin sensitivity, in real terms, is how well your body responds to insulin. High insulin sensitivity means your insulin is working well. Your cells are taking up glucose efficiently. Your correction factors are predictable. You correct, you wait, the number moves where you expected it to.
Low insulin sensitivity means the same dose does less. Your correction doesn't land where you expected. You correct, you wait, the number barely moves. You correct again. You're running higher than you should be for longer than you should be and you can't figure out why.
And I knooooooooow you've had those days. The insulin-feels-slow days. The days where you're doing everything right and the numbers aren't cooperating.
Some of those days might have had a very specific cause that had nothing to do with your insulin at all.
Here's the part I keep coming back to. In this study, the insulin dose didn't change. The only variable was sleep. And the insulin became 21% less effective.
One bad night. Not a bad week. Not months of chronic sleep deprivation. Not binging all 3 seasons of The Guilded Age (Gina & I destroyed that one in about 2 weeks). Just one night.
Now. I know you're doing some math right now. If one bad night reduces insulin sensitivity by 21%, and you've had more than one bad night... yeah. The math is what it is. But here's what I want you to take from this today. This isn't information designed to overwhelm you. It's information designed to reframe something.
Those mornings where your insulin felt slow. Where you corrected twice before breakfast and were still running higher than usual. Where you went through the whole checklist and came up empty.
What if it was the Tuesday night where you were up until 1am? What if it was the night the CGM alarmed three times and you never quite got back to deep sleep?
Not always. Not every time. But sometimes. And now you have a name for it.
Here's one more thing I want to say, because I think this is important. We can't always control our sleep. People with T1D have CGM alarms. We have lows at night. We have anxiety about lows. Sleep gets disrupted. That's real, and it's something we're going to talk about a lot over the next few weeks, because that disruption has its own causes and some of them we can actually do something about.
But right now, even before we get to solutions, knowing that sleep is a variable changes something. On the mornings after a rough night, you have context. You might watch your corrections a little more carefully. You might give yourself some grace about the numbers. You might think: OK, the deck is slightly stacked against me today, I know why, I'm going to be patient with myself.
That's not a cure. But it's information. And information changes how you manage. It changes how you feel about the numbers. And both of those matter.
21%. One night. I don't know about you - but this was like the equivalent of a man landing on the moon when it comes to understanding that my body is wild...to me.
I want to say something to the person who's been blaming themselves for numbers that didn't make sense. Who's been running the checklist at 7am and coming up empty and feeling like they missed something.
You didn't miss something obvious. You were missing a variable that wasn't on the list.
It's on the list now.
You're not doing a bad job. You're doing a difficult job, with information that was incomplete, and you've been managing it well enough to still be here, still be learning, still be showing up. That's not nothing. I'm proud of you.
Type 1 diabetes is relentless, but managing it doesn't have to be. New episodes drop every Monday, Wednesday, and Friday. Let's get this bread, I guess!
This is the script as read on the mic, lightly tidied for reading. Education, not medical advice. Talk to your care team before you change anything about your insulin.