Sometimes, blood sugar levels rise in the early morning hours even when you’ve carefully followed your diabetes medication and routine. Sometimes, though, elevated blood glucose (sugar) levels when you wake up may be caused by the dawn phenomenon — a common cause of early morning high blood sugar in people living with diabetes.

The dawn phenomenon affects about half of people with type 1 diabetes or type 2 diabetes. It usually happens in the early morning hours between 3 a.m. and 8 a.m., when the body releases certain hormones to help you wake up. While this process happens in everyone, people living with diabetes may not be able to respond to the hormone changes as effectively. This can lead to higher-than-normal blood sugar, even if you’ve been diligent about following your diabetes management plan.

Here, we’ll look at what causes the dawn phenomenon and share strategies that may help you manage high morning blood sugar.

What Is the Dawn Phenomenon?

According to the American Diabetes Association (ADA), the dawn phenomenon happens when the body releases hormones such as cortisol and growth hormone to the liver while you sleep. These hormones tell your liver to make more glucose (sugar) to give your body energy in the morning. In response, your pancreas should release insulin to balance out your blood sugar levels.

For people without diabetes, this process works smoothly — the body makes enough insulin to counteract the extra glucose created by the liver. But if you have diabetes, your body may not produce enough insulin, which can lead to hyperglycemia (high blood sugar levels). If hyperglycemia continues later into the morning, it’s called the “extended dawn phenomenon.”

You may experience high morning blood sugar levels from the dawn phenomenon for several reasons:

• Your body doesn’t produce enough insulin naturally.
• You have a higher insulin resistance.
• Your evening insulin dose or diabetes medication isn’t the right amount.
• You ate a carb-heavy evening meal or snack before bed.

Can the Dawn Phenomenon Be Treated?

Frequent high morning blood sugar can be managed by adjusting your overall diabetes care plan. To help better control your glucose, your doctor may recommend changes to your insulin therapy and certain lifestyle habits.

Finding the right treatment for the dawn phenomenon can take time. Because this early morning rise in blood sugar is usually short-lived, your doctor may not recommend simply increasing your dose of long-acting insulin. Though long-acting insulin can be adjusted to account for morning glucose levels, raising the dose too much can cause your blood sugar levels to drop too low in the middle of the night — before the dawn phenomenon begins.

To prevent low blood sugar while you sleep, your doctor might recommend using an insulin pump. This small device gives your body a steady flow of insulin through the night. It can also be set to deliver an extra dose when needed to help control the dawn phenomenon.

How To Help Your Body Reverse the Dawn Phenomenon Naturally

Lifestyle changes play a key role in managing diabetes and keeping your insulin levels under control. Following a healthy diet and staying active can help your body use insulin more effectively, including in the morning hours.

Go Low-Carb Before Bed

Your body uses carbohydrates (carbs) as energy. It does this by turning them into glucose — the body’s main energy source. The more carbs you eat, the higher your blood sugar levels rises. One way to help lower blood sugar in the morning is to avoid carb-heavy dinners or bedtime snacks that can raise your glucose overnight.

Keep in mind that carbs refer to sugar, starches, and fiber. To make sure you’re eating a healthy, low-carb dinner, you can use the Diabetes Plate method: fill half of a 9-inch plate with nonstarchy vegetables (like broccoli or spinach), one-quarter with lean protein, and one-quarter with healthy carbs such as beans or whole grains.

Don’t Skip Breakfast

If you wake up with high morning blood sugar, skipping breakfast might seem like the right move — but it can actually make things worse. Eating a healthy breakfast in the early morning can actually help your body when it’s experiencing the dawn phenomenon. This is because eating helps lower the levels of hormones that work against insulin, which can help bring your blood sugar back into balance.

Get Some Exercise After Dinner

Physical activity helps your body regulate blood sugar levels. To help prevent high morning glucose, try going for a walk or doing another light exercise after dinner. Even though you’re moving well before the dawn phenomenon sets in, the blood sugar-lowering effects can last through the night. If you notice that evening workouts cause your blood sugar to drop too low overnight, switch to a morning workout routine instead.

Before changing your exercise habits, it’s important to know whether your morning blood sugar rise is truly from the dawn phenomenon or from something else. An older theory, called the Somogyi effect, suggests that blood sugar can rise in the morning because the body releases extra glucose after blood sugar drops too low during the night. Although this theory isn’t strongly supported by current research, it can sometimes happen if your long-acting insulin dose is slightly too high.

When that happens, your blood sugar may drop overnight, leading your body to overcorrect — and you may wake up with higher glucose levels. Increasing your insulin dose further can make the problem worse, creating a cycle of highs and lows.

To check if this is happening, watch for signs of nighttime hypoglycemia — such as nightmares, night sweats, or restless sleep. The most reliable way to confirm is by using a continuous glucose monitor (CGM), which tracks your blood sugar throughout the night.

In general, exercise can sometimes cause hypoglycemia in people with diabetes who take certain medications. Talk to your doctor before starting or changing your exercise routine.

Stick to the Same Sleep Schedule

Getting a good night’s sleep is another way to support healthy blood sugar levels. If you’re waking up with high glucose, improving your sleep habits may help.

Research suggests that both total sleep time and sleep quality may play a role in blood sugar regulation. One study of adults with type 1 diabetes found that those who slept more than 6.5 hours a night had lower A1c levels than those who slept less. Other studies have found that spending more time in deep sleep is linked to lower A1c levels in teens and adults with type 1 diabetes.

Can Vinegar Control the Dawn Effect?

There’s limited evidence that vinegar, especially apple cider vinegar (ACV), may help control the dawn phenomenon. Some small studies suggest that consuming vinegar before bed can help lower fasting blood glucose.

One study looked at 80 adults with type 2 diabetes who managed their condition through diet and glucose-lowering medications, but not insulin injections. Participants took 30 milliliters (mL) of ACV daily for eight weeks while following dietary recommendations.

At the end of the study, those who took ACV had a significant decrease in fasting blood sugar compared to people who only followed the diet. They also showed a greater drop in A1c levels and an increase in insulin levels.

This means that ACV may help improve overall blood sugar control for some people. However, there’s not enough strong evidence to show that it specifically helps with the dawn phenomenon. If you’re interested in trying it, talk with your doctor first — especially if you take insulin or sulfonylureas, since vinegar can interact with these medications. Keep in mind that vinegar may also irritate your teeth or stomach.

Track Your Glucose Levels

Glucose monitoring is important if you’re living with diabetes. If you find you’re waking up with high blood sugar often, talk with your doctor.

Your healthcare provider may ask you to check your blood sugar at specific times during the night using a glucose meter, or they might recommend wearing a continuous glucose monitor (CGM). This device automatically records your blood sugar levels throughout the day and night.

By reviewing your glucose data, your healthcare provider can spot trends and determine whether your morning blood glucose levels are due to the dawn phenomenon and how to best manage your diabetes care.

Join the Conversation

On DiabetesTeam, people share their experiences with diabetes, get advice, and find support from others who understand.

Have you experienced the dawn phenomenon? Let others know in the comments below.