Some researchers believe the natural overnight release of what are called counter-regulatory hormones — like growth hormones, cortisol, glucagon and epinephrine — makes your insulin resistance stronger. This will make your blood sugar go up.
Why Is My Morning Blood Sugar so High?
A complex array of factors affects blood sugar levels, including hormones, diet, and lifestyle.
Q: I have prediabetes and now eat minimal carbs and sugar. My doctor told me to monitor my sugar levels, morning (fasting) and night. At night, two hours after eating, my sugar levels are between 112 and 130 mg/dL (6.2 to 7.2 mmol/L). But in the morning, my fasting sugar level is always higher than the night number. Why is that? What am I doing wrong?
There are a few reasons why your blood sugar may be elevated in the morning. First, it’s important to understand that certain hormonal changes that occur overnight may lead to high blood sugar levels (hyperglycemia) in the morning.
The Dawn Phenomenon
The dawn phenomenon refers to hormonal changes that cause your blood sugar to increase in the early morning hours before you consume breakfast. Your body makes extra blood sugar (glucose) overnight in order to avoid periods of low blood sugar (hypoglycemia) while you’re sleeping and to give you the energy you need to get out of bed.
In people without diabetes, insulin — the hormone that regulates blood sugar — also rises to keep blood sugar stable. However, in people with diabetes who are resistant to the effects of insulin or who don’t produce enough insulin, blood sugar may rise dramatically in the morning ( 1 ).
Although the dawn phenomenon is more common in people with diabetes, it can occur in those who have prediabetes as well.
Aside from the dawn phenomenon, there are a few other reasons why your blood sugar may be high in the morning.
Diet
It’s important to be aware that your nighttime meal choices can affect your morning blood sugar levels. For example, eating high-carb meals or snacking on sweets before bed can lead to elevated morning blood sugar levels.
To keep your blood sugar stable throughout the night, eat a dinner high in protein, healthy fats, and fiber, and moderate in complex carbs. Avoid carbs that tend to spike blood sugar, such as white bread and white pasta.
If you choose to eat a snack at night, opt for a high-fiber option balanced with protein or a healthy fat, such as a small apple with a tablespoon of natural peanut butter. This can keep your blood sugar more stable while you sleep.
Medications
If your doctor has prescribed you blood sugar medication, ensure that you’re following dosage and timing recommendations.
Taking the wrong dose or taking medications at the wrong time can cause blood sugar fluctuations and can lead to elevated morning blood sugar levels.
Lifestyle
Exercise and weight loss — if needed — are some of the best ways to increase blood sugar control in people with prediabetes.
Going for a walk after meals can significantly reduce blood sugar levels, which can improve overall blood sugar control. For example, research shows that walking for 15 to 20 minutes after meals can significantly reduce blood sugar levels over a 24-hour period in people with prediabetes and diabetes ( 2 , 3 ).
Choosing the right foods, taking medications as directed, losing weight if necessary, and exercising — especially after meals — are all ways to increase overall blood sugar control and decrease your chances of experiencing high blood sugar levels in the morning.
If you’re still experiencing high morning blood sugar levels after making these changes, consult your doctor for advice.
Jillian Kubala is a Registered Dietitian based in Westhampton, NY. Jillian holds a master’s degree in nutrition from Stony Brook University School of Medicine as well as an undergraduate degree in nutrition science. Aside from writing for Healthline Nutrition, she runs a private practice based on the east end of Long Island, NY, where she helps her clients achieve optimal wellness through nutritional and lifestyle changes. Jillian practices what she preaches, spending her free time tending to her small farm that includes vegetable and flower gardens and a flock of chickens. Reach out to her through her website or on Instagram.
Why Is My Blood Sugar High in the Morning?
That early morning jump in your blood sugar? It’s called the dawn phenomenon or the dawn effect. It usually happens between 2 and 8 a.m.
How It Works
Generally, the normal hormonal changes your body makes in the morning will boost your blood sugar, whether you have diabetes or not. If you don’t, your body just makes more insulin to balance everything out. You don’t even notice that it’s happening.
But if you have diabetes, it’s different. Since your body doesn’t respond to insulin the same as most, your fasting blood sugar reading can go up, even if you follow a strict diet.
The boost in sugar is your body’s way of making sure you have enough energy to get up and start the day. If you have diabetes, your body may not have enough insulin to counteract these hormones. That disrupts the delicate balance that you work so hard to keep, and your sugar readings can be too high by morning.
The effects of the dawn phenomenon can vary from person to person, even from day to day.
Some researchers believe the natural overnight release of what are called counter-regulatory hormones — like growth hormones, cortisol, glucagon and epinephrine — makes your insulin resistance stronger. This will make your blood sugar go up.
You may also have high blood sugar in the morning because:
- You didn’t have enough insulin the night before.
- You took too much or too little medicine.
- You ate the wrong snack before bedtime.
What You Can Do
If the dawn phenomenon affects you, try to:
- Eat dinner earlier in the evening.
- Do something active after dinner, like going for a walk.
- Check with your health care provider about the medicine you’re taking.
- Eat breakfast. It helps bring your blood sugar back to normal, which tells your body that it’s time to rein in the anti-insulin hormones.
- Eat a snack with some carbohydrates and protein before bed.
You’ll also want to avoid all sugar-sweetened beverages, like soda, fruit punch, fruit drinks, and sweet tea. Just a single serving can raise your blood sugar — and, in some cases, give you hundreds of extra calories.
If you have diabetes, chances are your blood sugar will be higher in the morning from time to time. That may not be something to be overly concerned about. If it happens for several mornings in a row, check it once during the night — around 2 or 3 a.m. — for a few nights. Then, take those numbers to your doctor. They can figure out if you really have the dawn phenomenon, or if something else is causing those higher morning numbers.
Show Sources
Diabetes Stops Here: “Why All the Morning Highs?”
Mayo Clinic: “What is the dawn phenomenon that some people with diabetes experience? Can anything be done about it?”
American Diabetes Association: “Diabetes Myths.”
Diabetes Forecast: “Why Is My Blood Glucose So High in the Morning?”
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