The dawn phenomenon is an increase in blood sugar levels, or hyperglycemia, that happens in the morning. This typically occurs between the hours of 3:00 a.m. and 8:00 a.m.
The dawn phenomenon is common in individuals with either type 1 or type 2 diabetes, and it has an estimated prevalence of
In people with diabetes, the dawn phenomenon can potentially elevate blood sugar to dangerous levels. This is why it’s important to try to manage the dawn phenomenon.
Read on to learn more about what causes the dawn phenomenon, the symptoms to look out for, and the steps that you can take to help manage it.
When levels of these hormones increase, your liver is stimulated to release glucose into your bloodstream. This gives your body a boost of energy to prepare you to wake up in the morning.
This natural increase in blood sugar occurs in all people. In individuals without diabetes, a rise in blood sugar causes cells in the pancreas to begin producing insulin to help keep blood sugar levels balanced.
What happens in people with diabetes?
Individuals that have diabetes may produce too little insulin. They may also have insulin resistance — when the cells of the body don’t respond to insulin. In this case, blood sugar levels remain high as you wake up in the morning.
If you use insulin as part of your diabetes treatment plan, it’s also possible that what you’re using may not be enough to manage your blood sugar levels through the night. This can happen for a couple of reasons.
If you inject long-acting insulin early, insulin levels in your bloodstream may not last until the morning. Or, if you use an insulin pump, the levels of insulin it administers in the night may be too low to counteract the dawn phenomenon.
Some research also shows that sleep quality may affect the dawn phenomenon. A
Even small changes may increase risk. For example,
Since even small increases in blood sugar levels can impact your health, managing the dawn phenomenon can be an important step in reducing your risk of diabetes complications.
The main symptom of the dawn phenomenon is high morning blood sugar. High blood sugar, also called hyperglycemia, is when your blood sugar reading is either over your blood sugar target or over 180 milligrams per deciliter (mg/dL).
High blood sugar due to the dawn phenomenon is often persistent and hard to manage. Generally, people that experience the dawn phenomenon don’t experience any physical symptoms.
However, some symptoms of hyperglycemia to look out for include:
If you notice that you frequently have high blood sugar in the morning, setting up a testing routine for several nights may be useful. To do this, test your blood sugar at the following times:
- right before going to bed
- in the early morning hours, such as between 2:00 a.m. and 4:00 a.m.
- first thing in the morning
Doing this can give you a good idea of your blood sugar levels at different times and when they’re beginning to rise. It can also serve as a helpful log if you visit your doctor to discuss high morning blood sugar.
In the Somogyi effect, blood sugar levels become too low at night, triggering your body to release additional glucose in response. When this occurs, you can wake up in the morning with high blood sugar.
There are a couple of things that can contribute to the Somogyi effect. These can include taking too much insulin or diabetes medications prior to bed or not eating a sufficient evening meal.
If you have high morning blood sugar, you can help determine what’s causing it by measuring your blood sugar in the early morning hours. The result can give you a better idea of what may be going on.
If you have normal or high blood sugar in the early morning hours, your high morning blood sugar is likely due to the dawn phenomenon. If you have low blood sugar in the early morning hours, your high morning blood sugar may be due to the Somogyi effect.
Setting up an evening routine can help you better manage high morning blood sugar. Follow the tips below to get started.
Avoid carbohydrates before bed
Eating a carb-filled snack prior to bedtime can cause blood sugar levels to rise. When this persists through the evening, the effects of the dawn phenomenon may be exacerbated.
Have dinner regularly
Always be sure to eat dinner in the evening. Not doing so may lead to hypoglycemia and the Somogyi effect.
To prevent having high blood sugar levels when you go to bed, avoid large meals and aim to have meals with a higher protein to carbohydrate ratio. Eating dinner earlier in the evening rather than later may also help.
Exercising in the evening hours can help to lower your blood sugar levels. Just be careful not to overdo it, as you risk experiencing hypoglycemia in the night. Focus on lighter activities like walking or yoga.
If you do have high blood sugar in the morning, being active during this time isn’t a bad idea either. This can help lower your blood sugar.
Consider the timing of insulin or medications
Considering the timing of insulin or other medications may also help. This is because it’s possible that you may not have enough in your system to counteract the effects of the dawn phenomenon in the early morning hours.
Potential things to try include:
- taking your insulin or diabetes medications prior to bed
- using long-acting insulin a little later in the day
- programing an insulin pump to give more insulin in the early morning hours
Adjusting your insulin or medications can potentially have other health effects. Because of this, always speak with your doctor before doing so. For example, using too much before bed may cause you to have low blood sugar during the night, which can also be dangerous.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommends seeing your doctor if your blood sugar is high more than three times in a 2-week period.
Your doctor may suggest continuous glucose monitoring to evaluate your blood sugar levels during the night. This can help determine if you’re experiencing the dawn phenomenon, the Somogyi effect, or something else.
Your doctor may also choose to adjust or switch your insulin or diabetes medication. For example, programing an insulin pump to give more insulin in the early morning hours can help to counteract the dawn phenomenon.
Overall, it’s possible that some trial and error will be needed in managing the dawn phenomenon. You may need to try different combinations of medication adjustments and lifestyle changes to reduce morning blood sugar levels.
The dawn phenomenon happens in people with either type 1 or type 2 diabetes. It’s caused by changes in hormones that lead to increases in blood sugar that begin in the early morning hours.
Many people that experience the dawn phenomenon won’t have any physical symptoms. The main symptom is having high blood sugar in the morning.
Because high blood sugar can lead to complications, see your doctor if you have high blood sugar more than three times in 2 weeks. A combination of treatment adjustments and lifestyle changes can help to manage the dawn phenomenon.