when things go bump in the night

One of the interesting things that I deal with is a rise in blood glucose overnight. I go to bed with a BG of 84 mg/dL (last night), and wake up with a BG of 104 (this morning)! My last meal was about 12 hours ago so what happened?!

This can be the results of two different processes: Dawn Phenomenon and Somogyi Effect.

The dawn phenomenon is a natural part of our bodies circadian rhythm. The evolutionary process developed this so that our ancestors could get up in the morning after a night of fasting and have enough energy to find food. This is great ability to have when your food can run away ( think woolly mammoth ) but not so great when you just need enough energy to open the refrigerator.

The Somogyi Effect is caused by the bodies response to night time hypoglycemia. When BG drops overnight the body reacts by secreting a hormone, glucagon, which signals the liver to start converting stored glucose (glycogen) into glucose. This of course raises your BG.

I notice that my before breakfast morning BG is always higher (about 20 points higher) than my bedtime BG. I believe it’s the dawn phenomenon at work. Have you experienced either the dawn phenomenon or the Somogyi Effect and how have you controlled it?

5 thoughts on “when things go bump in the night

  1. Maybe this doesn’t sound so nice, but I test EVERY night. It is very difficult to make a judgement with just one night’s results. You have to look for a pattern and be able to eliminate days when you have had unusual amounts of exercise. I am unsure if you use a pump. The rise in bg could also reflect a need to alter your basal rate during the night. You can do this if you have apump.


  2. If you check your bg twice during the night you should be able to figure out if the rise is due to a hypo, thus the somogyl cause. If you can eliminate that then you can KNOW that the cause is your need for more insulin during the later part of the night – the dawn phenomenon. If the rise in bg is due to the dawn phenomenon it is difficult to adjust without a pump. With a pump you can increase the basal hour by hour. I had similar problems before getting a pump. One cannot increase the long term insulin b/c in the beginning of the night such an increase will cause a hypo.


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