The Dawn Phenominon & The Symogi Effect, By Mr. Metabolism

| Feb 1, 1993

Dear Mr. Metabolism,

Please explain:

  1. The dawn phenominon
  2. The Symogi effect
  3. Why doesn't the diabetic use his/her stored liver glycogen when having low blood sugar? Is it all used up? Does a diabetic person store less glycogen? I have been aerobically exercising for 20 years and have a good muscle mass. About how much liver glycogen do we store?

Gudo Hallstone
Fresno, CA

The dawn effect is an increase in insulin resistance (or decrease in insulin sensitivity) caused by hormones released about two hours before you wake. These hormones are under the control of the pituitary gland, and thus the brain. The dawn effect is influenced by testosterone and tends to be more significant in men. It is highly variable from person to person. Your overnight insulin is taken to counter the dawn effect, and on average, diabetics take 20% of their insulin overnight. Mr. Metabolism requires more than 20% of his insulin at night.

The Symogi effect is the tendency of the blood sugar to rise as a result of low blood sugar. Low blood sugar can trigger release of hormones such as glucagon that raise blood sugar.

The liver would normally respond to declining blood sugar by increasing glycogenolysis, as I discussed above. But insulin inhibits glycogenolysis, and as you may have observed, low blood sugar occurs most often near an insulin peak.

Diabetics store slightly less liver glycogen than non-diabetics, but the difference is not thought to be very important. In well fed people, the carbohydrate stores are:

Muscle glycogen...1,700 calories

Liver glycogen..........500 calories

Plasma glucose...........12 calories

Mr. Metabolism (S. Robert King) has a masters degree from Harvard in Biochemistry and is a former biotechnology analyst with Montgomery Securities. Besides having type I diabetes, Mr. Metabolism is currently V.P., Technology for Metabolex, a biotechnology research firm in Hayward, CA.

If you have questions regarding diabetes research, write to Mr. Metabolism at 3715 Balboa St., San Francisco, CA 94121, or call our voice comment line at (415) 750-1958.

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Posted by Anonymous on 14 December 2008

Hello, I am a type I diabetic, age 23 and am a medical student in Chicago. I was diagnosed about 6 years ago. Through data that I have collected on myself, I am skeptical about the rationale behind the 'dawn effect.' Decreased insulin sensitivity due to hormones would imply that if you were to eat varying levels of carbohydrate upon waking, then (assuming you did not alter your insulin regimen to compensate for the dawn effect) you should experience corresponding variable hyperglycemia levels. That is to say, the more you eat in the morning, the higher your level of hyperglycemia. For me, this is absolutely not the case. I can eat either 30g of carbohydrate or 90g of carbohydrate and, assuming I do not factor in a dose for the dawn effect, know precisely how 'hyperglycemic' I will be. In practice, I supplement my morning meal insulin with a fixed surplus of insulin to cover the 'dawn effect.' If sensitivity is the given explanation, how can we explain my findings?

Chicago, IL

Posted by Anonymous on 20 May 2009

I take Metformin 500 mg am and pm. I have hi fasting glucose reading in the am. What if I tried to take Metforman500 in the am and Metformin 1000 in the pm. Do you think a higher dose of Metformin before bedtime will alter the "Dawn " effect. I know insulin would regulate it, but would po meds affect it???

Posted by Morris on 11 June 2009

Thank you for your website and comments Mr. M! I have just started to monitor my blood sugar. (Using my mother's testing unit.) I am not currently under a doctor's care, and am not formally diagnosed with diabetes. I was surprised to find morning FASTING levels of 149, 149, and 150 on three of the past four days. Then, during the day, my waking fasting levels are 103, 112, etc.

So, I went where everyone goes for accurate health information, the Internet. ;)

I am just learning about the Dawn Effect. Here's my additional two cents. I have just entered menopause in earnest. Hot flashes for the past two years. No menses for the past year. I have also put on additional belly fat in the last year, without changing my eating pattern. Now - you say that testosterone may play a part in the Dawn Effect. I wonder if there is an effect with the RELATIVE amount of Testosterone Hormone? Maybe I have the same amount I have always had, but now relatively less Estrogen and/or Progesterone, etc. What do you think? (That's rhetorical. I don't actually expect you to answer that.)

I think this question is worthy of study by some Masters or PhD student. Do Menopausal (and likely pre-diabetic) women also experience the Dawn Effect with morning fasting blood sugar? And could it be due to the loss of Estrogen, etc., making the percentage of Testosterone relatively greater? Thanks again for your site!

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