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 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. 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. The Dawn Phenomenon
Diet
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.
Whether you have type 1 or type 2 diabetes, a morning blood sugar high can be due to several causes. But with a little detective work and the help of your diabetes care team, you can isolate the cause and take steps to correct it. Here are three common scenarios:
1. The Dawn Phenomenon
This occurs during the night while you're asleep and the body releases stress hormones. This phenomenon usually occurs between 3 a.m. and 8 a.m. and involves growth hormone, cortisol, and adrenaline, which trigger the production and release of glucose from your liver. The end result of this chemical cascade is an increase in blood sugar.
“These hormones are designed to get us up and moving in the morning,” says endocrinologist Renee Amori, MD, assistant professor of medicine in the division of endocrinology at the Drexel University College of Medicine in Philadelphia. While everybody experiences these natural changes in hormone levels, in people with diabetes the body may not adjust appropriately. This can lead to higher-than-normal blood sugar at the start of the day. Testing for these elevated first morning blood sugars is one way to diagnose people with type 2 diabetes.
2. The Somogyi Effect
High morning readings can also be caused by the Somogyi effect, a rebound response that occurs when the body overcompensates for a low blood sugar reaction at night. If you take blood sugar–lowering medication — such as insulin — in the evening, this may cause you to have a hypoglycemic reaction while you're asleep, and your body will then release these stress hormones, causing you to have high blood sugar in the morning.
If this is contributing to your high morning blood sugar, Dr. Amori says, you may experience symptoms of hypoglycemia that can wake you from sleep in the middle of the night, including headache and excessive sweating. You may also experience difficulty waking in the morning. If your physician is increasing your evening diabetes medication to lower your morning blood sugar but your blood sugar keeps going up, you may be experiencing the Somogyi effect.
3. Waning Insulin
The third common cause of high morning blood sugar levels is waning amounts of insulin, which means your insulin levels are going down and no longer keeping your blood sugar in check. As a result, you wake up to an elevated reading.
Finding the Cause of Your Morning Blood Sugar High
Though the three most likely causes of high morning blood sugar can all be treated, first you have to know which one is the source of your condition. "If you’re not sure, you might have to take the somewhat inconvenient step of waking up to check your blood sugar levels in the middle of your sleep pattern (for example at 3 a.m. if you go to bed at 11 p.m.)" suggests Amori. Here’s why:
- Consistent blood sugar from bedtime until about 3 a.m. and then a rise suggests the dawn phenomenon.
- Low blood sugar at 3 a.m. suggests the Somogyi effect.
- Blood sugar that increases from bedtime to 3 a.m. and then is even higher when you wake is probably due to waning insulin.
Using a continuous glucose monitor enables you to get this information without having to wake up for it. "These monitors potentially help identify patterns and severity of high and low blood sugars," explains Amori.
Treating High Morning Blood Sugar
A blood sugar high in the morning "can be tough to treat,” acknowledges Amori, but with the help of your medical team, you can try different approaches. Talk with your doctor about these strategies:
Adjust your pump. If you’re testing high regularly and you use an insulin pump, you might be able to program it to help manage your morning highs.
Check blood sugar before bed. Granted, many people have morning high blood sugar after an acceptable blood sugar before bedtime. Even so, "don't go to bed with high blood sugar," cautions Amori.
Take basal insulin. Taking basal insulin at bedtime could help, but be sure to clear any changes in dosing with your physician before you try it.
Adjust medication. If in fact your high morning blood sugar is a rebound response to a low blood sugar level while you’re asleep, you might need to change the dose of any medication you take in the evening that could be causing low blood sugar. Talk with your doctor about whether your medication schedule should be adjusted to treat morning highs.
Have a healthy pre-bed snack. For those experiencing the Somogyi effect, a healthy mixed snack of protein and carbohydrates could help prevent your blood sugar roller coaster at night. Amori advises working with a registered dietitian if you’re not sure how to fit a pre-bed snack into your daily diet.
Increase physical activity. Being physically active during the day can help you manage blood sugar more effectively in general. If your diabetes is treated with insulin or you have a concern about low blood sugar, find out how to exercise safely before increasing your physical activity.
High morning blood sugar levels are a concern, especially if they happen regularly and seem to make it hard to meet your blood sugar goals. But taking steps to address these morning highs can improve your overall diabetes management and stave off diabetes-related complications.