Skip to content
My WebMD Sign In, Sign Up

Diabetes Health Center

Font Size

Dawn Phenomenon and the Somogyi Effect - Overview

The dawn phenomenon and the Somogyi effect cause high blood sugar levels, especially in the morning before breakfast, in people who have diabetes.

Dawn phenomenon

The dawn phenomenon is a normal rise in blood sugar as a person's body prepares to wake up.

  • In the early morning hours, hormones (growth hormone, cortisol, and catecholamines) cause the liver to release large amounts of sugar into the bloodstream. For most people, the body produces insulin to control the rise in blood sugar.
  • If the body doesn't produce enough insulin, blood sugar levels can rise. This may cause high blood sugar in the morning (before eating).

Somogyi effect

If the blood sugar level drops too low in the early morning hours, hormones (such as growth hormone, cortisol, and catecholamines) are released. These help reverse the low blood sugar level but may lead to blood sugar levels that are higher than normal in the morning. An example of the Somogyi effect is:

  • A person who takes insulin doesn't eat a regular bedtime snack, and the person's blood sugar level drops during the night.
  • The person's body responds to the low blood sugar by releasing hormones that raise the blood sugar level. This may cause a high blood sugar level in the early morning.

How can you tell the difference?

The Somogyi effect can occur any time you or your child has extra insulin in the body. To sort out whether an early morning high blood sugar level is caused by the dawn phenomenon or Somogyi effect, check blood sugar levels at bedtime, around 2 a.m. to 3 a.m., and at your normal wake-up time for several nights. A continuous glucose monitor could also be used throughout the night.

  • If the blood sugar level is low at 2 a.m. to 3 a.m., suspect the Somogyi effect.
  • If the blood sugar level is normal or high at 2 a.m. to 3 a.m., it's likely the dawn phenomenon.
1

WebMD Medical Reference from Healthwise

Last Updated: June 24, 2013
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Dawn Phenomenon and the Somogyi Effect Topics

Is This Normal? Get the Facts Fast!

Check Your Blood Sugar Level Now
What type of diabetes do you have?
Your gender:

Get the latest Diabetes newsletter delivered to your inbox!


or
Answer:
Low
0-69
Normal
70-130
High
131+

Your level is currently

If the level is below 70 or you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.

People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.

Congratulations on taking steps to manage your health.

However, it's important to continue to track your numbers so that you can make lifestyle changes if needed. If you are pregnant always consult with your physician.

Your level is high if this reading was taken before eating. Aim for 70-130 before meals and less than 180 two hours after meals.

Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.

One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.

Did You Know Your Lifestyle Choices
Affect Your Blood Sugar?

Use the Blood Glucose Tracker to monitor
how well you manage your blood sugar over time.

Get Started

This tool is not intended for women who are pregnant.

Start Over

Step:  of 

Today on WebMD

Diabetic tools
Symptoms, diagnosis, treatment, and more.
woman flexing muscles
10 strength training exercises.
 
Blood sugar test
12 practical tips.
Tom Hanks
Stars living with type 1 or type 2.
 
Woman serving fast food from window
Video
Can Vinegar Treat Diabetes
Video
 
Middle aged person
Tool
are battery operated toothbrushes really better
Video
 

Prediabetes How to Prevent Type 2 Diabetes
Article
type 2 diabetes
Slideshow
 
food fitness planner
Tool
Are You at Risk for Dupuytrens Contracture
Article