How to Fix High Morning Blood Sugars (Dawn Phenomenon)?

August 7, 2019

There are various possible causes of a high blood sugar level in the morning:

  1. The Dawn Phenomenon which is a natural rise in blood sugar due to a surge of hormones secreted at night which trigger your liver to dump sugar into your blood to help prepare you for the day.
  2. Having high blood sugar from the night before which continue through the night into the morning.
  3. Reactive hyperglycemia which is also called the Somogyi Effect. This is when low blood sugar in the middle of the night triggers your liver to dump sugar into your blood in an attempt to stabilize your blood sugar.

Why Are My Blood Sugars High in the Morning?

adobe stock photo

There is a simple strategy for diagnosing the source of high blood sugars in the morning.

  1. Test your blood sugar before bed.
  2. Test your blood sugar in the middle of the night.
  3. Test your blood sugar in the morning.

It takes a little bit of effort, but you only need to do it a few times to diagnose the issue.

The Somogyi Effect is less common than the Dawn Phenomenon, according to an article published by The Polish Journal of Endocrinology. To diagnose either of these phenomena, scientists recommend checking blood sugar levels for several nights specifically between 3 a.m and 5 a.m. or using a continuous glucose monitoring system (CGM).

Many healthcare practitioners are now offering the use of a loan CGM for a few days which can be helpful to observe nighttime blood sugar activity. Try asking your doctor about using a CGM to learn about your blood sugars at night.

How to Fix High Blood Sugars in the Morning

The Dawn Phenomenon

The Dawn Phenomenon refers to a surge of hormones excreted by your body in the early morning hours. These hormones rise each night around the same time to prepare your body to wake. Basically, your body is starting the engine, releasing some fuel, and prepping to go for the day.

The Dawn Phenomenon occurs in all humans regardless of whether they have diabetes. However, many people with diabetes also experience a rise in blood sugar. In people without diabetes, the body’s natural insulin response prevents the blood sugars from rising.

These hormone surges affect those with type 1 diabetes and according to an ADA published journal, about half of people with type 2 diabetes. Scientists have suggested that the Dawn Phenomenon experienced by those dependent on insulin is mostly caused by a surge in nighttime growth hormone secretion. Other hormones secreted in this surge include cortisol, adrenaline, and glucagon.

These hormones trigger the conversion of the liver’s glycogen stores into glucose which is then dumped into the blood in a process called glycogenolysis.

The University of California, San Francisco

Our in-house diabetologist, Dr Paresh Ved, suggests several things that you can try to combat the effects of the Dawn Phenomenon:

• Avoid carbohydrates at bedtime.
• Adjust your dose of medication or insulin. (If you take long-acting insulin such as Lantus, be aware it doesn’t last a full 24 hours. This means you may want to try taking it at night or splitting the dose by taking half in the morning and the other half 12 hours later.)
• Switch to a different medication.
• Adjust the time when you take your medication or insulin from dinnertime to bedtime.
• Use an insulin pump to administer extra insulin during early-morning hours.

What Works for Some People

Many people get overly concerned about dawn phenomenon. If most of your night is spent with normal blood sugars and you experience a small, temporary increase in the morning, this is likely nothing to worry about. For those that are otherwise in a target range, the morning increase is often less than they experience during a typical meal and even more short-lived.

Due to the Dawn Phenomenon, people are more resistant to insulin first thing in the morning. You may want to limit carbohydrates during the hour or two after you wake up. Insulin-users may need to have a higher insulin-to-carb ratio and take more insulin in the morning than during other parts of the day.

• Some insulin users take a dose of fast-acting insulin as soon as they wake to combat the Dawn Phenomenon and prevent blood sugars from rising first thing in the morning.
• Others find that exercise first thing in the morning helps to avoid lows–in part because of the Dawn Phenomenon.
• You can also try to split your basal dose of Levemir, Lantus, or Tresiba so that you get more even coverage from your basal (do this with support from a healthcare provider).
• If you use an insulin pump, try experimenting with higher basal doses in the early morning to combat Dawn Phenomenon.

High Blood Sugars from the Night Before

If you are experiencing high blood sugar in the morning as a result of elevated blood sugar from the night before, there are several things you could try:

• Eat fewer carbohydrates during the evening hours.
• Add evening exercise like an after-dinner walk.
• In consultation with your doctor, increase blood-sugar lowering medication or insulin.

Reactive Hypoglycemia (Somogyi Effect)

This is also known as rebound hypoglycemia or the Somogyi Effect.

If when you test in the middle of the night you find your blood sugar is going low, this could be the reason for elevated morning blood sugar levels. Your body is essentially in panic mode and alerts you by secreting counter-regulatory hormones like glucagon and epinephrine (adrenaline) which trigger the liver to change its reserves of glycogen into glucose. In short, your body senses a low and dumps as much sugar as it can into the blood in an attempt to get enough fuel to function.

Here are some things you could try to reduce this occurrence:

• Eat a carbohydrate snack before bed.
• Reduce blood sugar-lowering medication or insulin in the evening.
• Reduce your long-acting insulin dose.
• Change your exercise schedule from afternoon or evening to first thing in the morning.

Make sure you don’t ignore reactive hypoglycemia.

Over time, your body’s response to low blood sugar levels may change due to hormone changes, leaving your body unable to warn you with low blood sugar symptoms and unable to trigger the liver into dumping sugar into your blood. Also, if other low blood sugar episodes have occurred earlier the same night or excess exercise has taken place, the liver may have already depleted its reserves of glycogen and may not be able to secrete glucose and raise your blood sugar.

This is why being aware of what is happening and solving the likelihood of this event is important. Some people with diabetes periodically check their blood sugar levels around 3 a.m. to stay aware of nighttime blood sugar trends. If you find that low blood sugars are occurring without any symptoms–this is called hypoglycemia unawareness.


COVID-19 NOTICE: Easy online consultation is now available with Dr. Paresh Ved.
Book Now
close-image