Understanding the Dawn Phenomenon

Waking up with high blood sugar? It’s more common than you think.

In fact, even people who don’t have diabetes can have higher blood sugars in the morning. This is because of an effect called the “dawn phenomenon.” Never heard of it? Don’t worry! We’ll explore what the dawn phenomenon is, why it’s raising your morning blood sugars, and share tips for keeping your morning readings on target.

High blood sugar in the morning can be caused by many things. While diet and medications are some of the more common culprits, normal body processes can also be to blame.

The dawn phenomenon is seen in people with type 1 and type 2 diabetes, and isn’t necessarily caused by something that you are or are not doing.

In the early hours of the morning, even before you are aware of it, your body is getting ready for the day ahead.  Certain hormones needed for energy peak in these early hours. The liver works hard overnight to produce blood sugar (aka glucose), and when signaled by this surge of hormones, releases the glucose into the bloodstream to get ready to get up. In a person who does not have diabetes, insulin ensures the blood sugar levels don’t get too high. In a person with diabetes, this early morning release of energy can cause a high blood sugar.

The dawn phenomenon, also called the dawn effect, can be worrisome if it becomes a persistent occurrence. Side effects can include an elevated A1c and higher risk of diabetes related complications. If your blood sugar is within the safe zone (80-180) the majority of the time, your A1c can remain in a good range, even with the occasional morning high blood sugar reading. However, if you have trouble staying in the zone and are experiencing many high morning readings, you may be at risk for an elevated A1c. We recommend the following strategies for preventing high morning readings and keeping your sugars “in the zone:”

Get enough sleep. Aim for at least 7 hours per night. Studies have shown that adequate sleep helps to keep cortisol low. Cortisol is a hormone that tells the liver to release glucose, so lower levels of cortisol is good. Your Brook dashboard helps you track your sleep, and you can ask one of our Health Coaches for some tips on getting high quality shut-eye.

Watch carbs at bedtime. Having dinner a few hours before bed and eating a moderate amount of carbs supports a healthy blood sugar reading in the morning. Not sure what a moderate amount of carbohydrates looks like? Check out the Brook Healthy Plate for guidance. Taking meds? Always talk to your doctor before making drastic changes.

Pro-tip: Want an evening snack, but trying to avoid carbs at night? Don’t go hungry! Have a small handful of nuts or a hard boiled egg to get in some healthy fats and proteins while still keeping it low carb.

Get active after dinner. Take a brief 10 – 15 minute walk after dinner to help lower blood sugar before bed and minimize the effects of early morning hyperglycemia. Look here for some tips on getting more physical activity into your day.

Eat a balanced breakfast. Eating a balanced meal soon after waking up can trigger the release of insulin and help to lower blood sugar. Not sure what a balanced breakfast looks like? Talk to one of our Health Coaches for some ideas and recipes.

Talk to your doctor about med changes. Although it may be warranted if you are experience frequent morning high blood sugars, risking a low blood sugar by making medication adjustments without professional advice can be dangerous. Chat with your doc at your next check up to see if a medication change or adjustment is the right way to go.

Only your healthcare team can truly determine if the dawn phenomenon is causing your morning readings to be high. If you suspect that your morning high blood sugar readings are a result of the dawn phenomenon, try testing your blood sugars consistently before meals, upon waking, and around 2 am for 2-3 days. Having this information will help you and your doctor make the best decisions for your care, enabling you to be the most successful in keeping your sugars in the zone.

For more tips on managing blood sugar, the dawn phenomenon, and staying “in the zone,” chat with us in your Brook app!

Image of Brook Health Expert Kelsea
Reviewed by Kelsea Hoover, MS, RDN​

on February 20th, 2020. Kelsea is a Registered Dietitian with her Master's degree in Nutrition from Bastyr University in Kenmore, WA, and is one of our Health Coaches.