Why Is My Blood Sugar High in the Morning? 2 Hidden Causes and How to Fix Them

"Doc, my blood sugar is normal when I go to bed. Sometimes it's in the 130s after dinner. But when I wake up, it's 180, even 250. I didn't eat a thing overnight! Why?"

I hear this question all the time. If this sounds like you, you are not alone. And you are not doing anything "wrong" in your sleep.

There are two main reasons your fasting blood sugar can be high in the morning. Once you know which one you have, you can fix it.

First, a quick refresher on glucose

Glucose is a simple sugar. It's the main fuel most of your cells use to do their jobs. Your brain loves it.

Glucose is so important that your body can make its own. Your liver makes glucose from other building blocks. So even if you never ate sugar or starch again, your body would still have the glucose it needs.

That is the key to understanding what happens overnight.

1️⃣ Reason #1: The dawn phenomenon

Every morning, before you wake up, your body gets you ready for the day. It releases hormones like cortisol. These hormones tell your liver, "Send out some glucose. We need energy to start the day."

This is normal. Everyone does it.

The problem comes with insulin resistance, which means your body doesn't respond to insulin well. Insulin's job is to move glucose out of your blood and into your cells. When insulin works too slowly, that morning glucose hangs around in your blood. So you wake up with a high reading, and you may even feel sluggish.

2️⃣ Reason #2: The Somogyi effect (the rebound)

This one usually starts at dinner.

A meal heavy in sugar or starch sends your blood sugar up fast. Your body works hard to bring it back down, but it overcorrects. Your blood sugar drops too low during the night.

A low blood sugar is stressful for your body. So it releases stress hormones like cortisol, adrenaline and glucagon to push your sugar back up. Often it pushes too hard. By morning, you have a high reading.

Too much insulin or other diabetes medicine can cause the same overnight dip and rebound, even when dinner was light.

How to tell which one you have

First, talk with your doctor. Then, if you have a glucose meter, check your blood sugar:

1. Before dinner
2. After dinner
3. In the middle of the night
4. When you wake up

Low in the night (below 70), then high in the morning? That points to the rebound, the Somogyi effect.

Steady all night, then a jump when you wake up? That points to the dawn phenomenon.

A continuous glucose monitor makes this even easier, because it tracks your sugar all night while you sleep.

How to fix it

For the dawn phenomenon: the root problem is insulin resistance. To fix it, lower your body's need for insulin. That means cutting back on sweetened foods, sweet drinks and refined starches long enough for your body to reset and start listening to insulin again. Managing stress helps too, because stress raises cortisol.

For the rebound:

• Ask your doctor to review your medicines, especially insulin or pills like glipizide. You may be taking more than you need. Never change your insulin dose on your own.
• Look at your dinner. Eat less starch, sugar, dessert and alcohol. Eat more protein, natural fats and vegetables, so the energy from your meal is released slowly.

Many of my patients on insulin worry about eating enough carbs to "cover" their dose. That fear makes sense. But try shifting your focus from one number to nourishing your body. When you feed your cells real food, your body is very good at keeping your glucose where it belongs.

Bottomline?

High morning blood sugar has a cause, and it can be fixed. Check your overnight numbers, find your pattern, and work with your doctor on the right changes. Ideally, your fasting blood sugar should be around 100 or a little lower, but it should not drop below 70.

Want help with this? Request a consultation. I see patients by video in Mississippi, Alabama, Tennessee, Louisiana, Idaho, Oregon and Antigua & Barbuda.

Your health is your wealth.

Dr. Amina