Based on his scientific observations, Michael Somogyi, a biochemist and professor at the University of Washington, hypothesized in the 1950s that “hypoglycemia” could cause “hyperglycemia.” Today, we talk about the “Somogyi effect,” which is characterized by elevated blood sugar in the morning following an undetected and untreated night-time hypoglycemia in diabetics who inject insulin. To offset the hypoglycemia, the body secretes counter-regulatory hormones, such as glucagon and adrenaline. This is also called “rebound hyperglycemia.”

Although this hypothesis has never been scientifically proven, professionals working in the field of diabetes suspect that the Somogyi effect is involved when in a person whose insulin dosage at bedtime is being gradually increased has constant hyperglycemia in the morning.

If your diabetes is being treated with insulin, and if your blood sugar is elevated when you awake in the morning (above 7 mmol/L), you should measure your blood glucose around 3 a.m., or during the peak insulin action from your bedtime injection. Do this for at least two consecutive nights. If you find that your measured blood glucose is less than 4 mmol/L, you are in a state of hypoglycemia and the Somogyi effect could account for your morning hyperglycemia.

Identify the cause of the hypoglycemia to prevent rebound hyperglycemia

Here are a few causes of nocturnal hypoglycemia:

  • The dose of insulin at bedtime is too high
  • A problem related to your insulin-injection technique
  • Consuming fewer than usual carbohydrates at supper or during the evening
  • Drinking alcohol on an empty stomach or excessively
  • Unusual physical activity during the day

When you find the cause, discuss with your physician whether you should reduce your insulin dosage at bedtime or change the type of insulin.