Why Sleep Deprivation Hits Harder When You Have T1D
Sleep deprivation reduces insulin sensitivity in everyone. That's not a T1D-specific finding. Here's what is. In people without diabetes, the system has a feedback loop. Insulin sensitivity drops, blood sugar ticks up slightly, the...
The episode, word for word
Quick question.
You go to bed at a perfect 110. Flat arrow. No active insulin. You did absolutely everything right. Textbook. You should be very proud.
You wake up at 182.
No low in between. No alarm. You didn't eat anything. You didn't stress in your sleep, as far as you know. You just... slept.
And you're standing in your kitchen at 6am doing the checklist. And the checklist has nothing on it. Everything checks out. Nothing happened.
Here's the thing. Something happened. You just weren't awake for it.
My name is Neil Greathouse, and this is Your Best T1D Year.
All right. Welcome back. We're in Week 3 of the Sleep Challenge, and this week I want to get into actual mechanisms. Not just "sleep matters, trust me." The actual biological things happening in your body while you're lying there thinking you're just sleeping.
Some of it is wild.
OK. So. Your liver.
Your liver has a 3am shift. It didn't ask. It didn't put this on its calendar. It doesn't text before it shows up. It has never once, in your entire life, checked whether this was a convenient time. It just shows up. Every single night. Whether you're sleeping well or not. Whether you know it's happening or not. Without warning, without remorse, like a contractor who has the code to your house and just sort of appears.
Here's what's actually happening. Between roughly 3am and 8am, your body releases what's called a pre-dawn hormonal surge. Cortisol, growth hormone, glucagon, epinephrine, all of them, all at once, slowly ramping up to prepare your body for waking up. And in response to all that, your liver does something called hepatic glucose output. Which sounds like a Jurassic Park sequel. "Hepatic Glucose Output." Opens summer 1997. Chris Pratt, dinosaurs, your liver.
What it actually means is your liver is building brand new blood sugar out of protein and fat at 3am. Just manufacturing glucose and releasing it into your bloodstream. On its own schedule. Without anyone's permission.
This whole thing has a name: the dawn phenomenon. The dawn phenomenon sounds like a prog rock concept album from 1977. Or a Taylor Swift three-album arc with a 3am bonus track edition. It is neither of those things. It's just your liver doing overtime while you sleep.
OK. Here's the part where it gets specifically personal for us.
For people without T1D, this whole situation is a complete non-event. The hormones go up. The liver drops glucose into the blood. The pancreas notices, produces a little extra insulin, and the whole thing resolves quietly before that person is even conscious. They wake up. They make coffee. They look at their phone. They have absolutely no idea any of this was happening.
Must be nice.
For us? The hormones go up. The liver does its thing. And the pancreas... doesn't. Can't. Isn't there. And so the glucose just sits. Rising. Until we wake up to a 182 we can't explain, standing in the kitchen in our pajamas at 6am, holding an insulin vial up to the light like it's going to tell us something.
Here's my confession. I have been doing that exact thing for thirty-four years. Waking up to numbers I couldn't account for. Standing in the dark in my kitchen. Squinting at a vial of insulin like it owed me an apology. Running through every possible suspect. The food, the site, the stress, the banana bread. And the whole time, my liver was back there running its 3am shift and I didn't even know to look at it.
I was a detective who'd been interviewing the wrong witness for three decades.
Now I want to say something, because I know some of you are sitting with that information and feeling a specific kind of frustrated. And that's fair. Information that should have been in your original briefing and wasn't is frustrating. If you want to take a second and feel some feelings about the dawn phenomenon, you're allowed.
What I'll add is this: knowing it's happening changes how you respond to it. On the mornings where you wake up higher than you went to bed with no obvious reason, you now have a name for what might have happened. It's not a failure. It's your liver on its night shift. It's a mechanism. And mechanisms can be worked with.
We'll talk about what to actually do about this in June, when we get into solutions. For right now, tonight, I want you to do something simple.
Pull up your overnight CGM graph from last night. Look at the shape of it between 3am and 8am.
Do you see a rise? Even a gradual one, starting somewhere around 3 or 4am, when your blood sugar was otherwise flat? Just flat and then... up?
That might be the dawn phenomenon. Or it might be something else. But I want you to start looking for the pattern in your own data.
Don't change anything tonight. Just look.
To the person who has been waking up to unexplained morning highs for years and blaming themselves for a checklist that never had the right answer on it.
You weren't missing something obvious. You were missing a mechanism that nobody taught you.
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 I'm genuinely proud of you for still showing up.
Type 1 diabetes is relentless, but managing it doesn't have to be. New episodes drop every Monday, Wednesday, and Friday. You're not doing a bad job, you're doing a difficult job. Nobody remembers easy.
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.