Waking Up to a 105 Blood Sugar in the Morning: Should You Actually Worry?

You wake up, prick your finger, and the little digital screen flashes a 105. It’s not quite "normal," but it’s definitely not the scary-high numbers you see in medical textbooks. You might feel totally fine. Or maybe you're a bit groggy. Either way, that 105 blood sugar in the morning sits in a weird, frustrating middle ground.

Is it a big deal?

Honestly, it depends on who you ask and what your body did the night before. If you’ve been told that anything over 99 mg/dL is "prediabetes," seeing a 105 can feel like failing a test you didn't know you were taking. But the human body isn't a calculator. It’s a messy, biological machine that reacts to stress, sleep, and even the "Dawn Phenomenon"—that strange quirk where your liver dumps sugar into your blood just to help you wake up.

What a 105 Really Means for Your Metabolism

In the strict world of clinical guidelines, like those from the American Diabetes Association (ADA), a fasting blood glucose between 100 and 125 mg/dL is categorized as prediabetes. So, technically, a 105 blood sugar in the morning puts you in that camp.

But hold on.

One single reading of 105 is just a snapshot. It’s like taking a photo of a car while it’s speeding; it doesn't tell you the whole story of the trip. Your doctor is going to care much more about your A1C, which is a three-month average of your blood sugar levels. If your A1C is below $5.7%$, that 105 might just be a morning fluke. However, if you’re consistently hitting 105, 107, or 110 every single morning, your body is sending you a subtle memo. It’s saying that your insulin isn't quite keeping up with the demands of your system during the overnight hours.

The Dawn Phenomenon and Why Your Liver is "Helping" Too Much

Have you ever wondered why your sugar is higher after eight hours of not eating than it was right before you went to bed? It feels counterintuitive. It’s called the Dawn Phenomenon. Around 4:00 AM or 5:00 AM, your body starts pumping out hormones like cortisol, adrenaline, and growth hormone.

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They’re basically your internal alarm clock.

These hormones signal the liver to release stored glucose to give you the energy to start your day. For someone with perfect insulin sensitivity, the pancreas just releases a little extra insulin to compensate, and the sugar stays flat. But if you have a bit of insulin resistance, that 105 blood sugar in the morning is the result of your liver over-delivering and your pancreas under-responding.

Then there’s the Somogyi effect. This is rarer but happens if your blood sugar drops too low in the middle of the night—maybe you took too much medication or exercised intensely without a snack. Your body panics, releases stress hormones, and "rebounds" your sugar high by the time you wake up.

Stress, Sleep, and the "Hidden" Spikers

We talk a lot about carbs, but we don't talk enough about stress. If you had a rough night of sleep—maybe the neighbor’s dog wouldn't stop barking or you were tossing and turning over a work project—your cortisol levels stay elevated. Cortisol is the enemy of low blood sugar. It tells your cells to ignore insulin so there’s plenty of "fuel" (sugar) available for your perceived "fight or flight" situation.

A 105 reading might have nothing to do with what you ate for dinner and everything to do with the fact that you only got five hours of restless sleep.

Dehydration is another sneaky culprit. If you wake up parched, your blood volume is lower, which makes the concentration of glucose in your blood appear higher. It’s a simple math problem: same amount of sugar, less liquid to dilute it. Sometimes, drinking a big glass of water and re-testing 20 minutes later can show a slightly lower number, though the "fasting" rule still technically applies to that first poke.

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Why Some Experts Think 105 is Actually "Okay"

There is a growing debate among metabolic health experts, including people like Dr. Peter Attia or proponents of the "Functional Medicine" approach, about what "optimal" really looks like. While the ADA says 100 is the cutoff, some argue that looking at glucose in isolation is a mistake.

If your fasting insulin is very low (meaning your body doesn't have to work hard to keep you at 105), you might be in better metabolic shape than someone with a fasting glucose of 90 who has sky-high insulin levels to maintain it.

Context matters.

• Are you on a low-carb or ketogenic diet? Sometimes long-term keto followers experience "adaptive glucose sparing." This is where the muscles refuse to take up glucose because they’re saving it for the brain, leading to a slightly higher fasting number (like 105) despite excellent health.
• Are you an athlete? Intense training can sometimes cause temporary elevations in fasting glucose as the body stays in a state of high turnover and repair.

Real Steps to Move the Needle

If you’re seeing 105 and you want to get back into the 80s or 90s, you don't necessarily need medication. Small, weirdly specific tweaks often work better than "dieting" in the traditional sense.

Try the "Post-Dinner Stroll." It sounds like something your grandparents would do, but walking for just 15 minutes after your last meal of the day can significantly lower your fasting glucose the next morning. It clears out the excess sugar before you go to sleep, so your body doesn't have to deal with it all night.

Vinegar might actually help too. There’s decent evidence (often cited by researchers like Carol Johnston at Arizona State University) that taking a tablespoon of apple cider vinegar in water before bed can improve insulin sensitivity and lower morning glucose. It’s not a magic bullet, but it’s a cheap, easy experiment.

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Also, look at your "Carb Ceiling." Everyone has a limit on how many carbohydrates they can process in the evening. If you’re eating pasta at 8:00 PM and seeing a 105 blood sugar in the morning, your body is telling you that the timing is the problem. Moving your largest meal to lunch and having a lighter, protein-focused dinner can often fix the morning spike within a few days.

Beyond the Finger Prick

If you’re really curious (or worried), a Continuous Glucose Monitor (CGM) is the gold standard. It’s a little sensor that stays on your arm for two weeks. Instead of one data point at 7:00 AM, you see the whole "mountain range" of your blood sugar.

You might find out that your 105 is actually your lowest point of the day, or you might see that you’re spiking to 160 at 3:00 AM. That kind of data is much more useful than a single 105.

Ultimately, 105 is a yellow light. It’s not a red light—you aren't in an emergency—but it’s not a green light either. It’s a signal to pay attention. It’s an invitation to look at your sleep hygiene, your evening stress, and maybe how many late-night snacks are sneaking into your routine.

Actionable Next Steps:

• Test your A1C: Get a lab test to see if your 105 is a consistent pattern or a one-off event.
• Prioritize 7-8 hours of sleep: Cortisol from sleep deprivation is a primary driver of elevated morning glucose.
• Check your magnesium levels: Magnesium plays a massive role in insulin signaling, and many people are deficient.
• Hydrate before bed: Ensure you aren't waking up in a concentrated state due to simple dehydration.
• Audit your evening meal: Try reducing carbohydrates in your final meal of the day for three days and see if the morning number drops.

A 105 blood sugar in the morning is manageable. It’s a "nudge" from your metabolism. By catching it at this stage, you have the opportunity to make small shifts that prevent that 105 from turning into a 125 or higher down the road. Focus on the trends, not the daily fluctuations, and use the number as a tool for curiosity rather than a source of anxiety.