Contending With the Lows While Catching Some Z's

---

Hypoglycemia during sleep impairs consolidation of declarative memory in type 1 diabetic and healthy humans, by K. Jauch-Chara and colleagues. Diabetes Care 30:2040-2045, 2007

What is the problem and what is known about it so far?

Many times, people with type 1 diabetes will experience hypoglycemia (or too-low blood glucose levels) while sleeping. Some studies have shown that the brain stores memories while we sleep, and other studies have shown that having low blood glucose can impair memory and the brain’s ability to think through difficult tasks.

Why did researchers do this particular study?

Researchers wanted to build on these earlier studies and test the effects of low blood glucose during sleep on the memory process.

Who was studied?

Adults with type 1 diabetes.

How was the study done?

During the evening, 16 people with diabetes and 16 without viewed 40 random word pairs (for example, flag-camp) on a computer and then were tested on them. Afterwards, some nights the researchers lowered the test subjects’ blood glucose, while the other nights, the researchers kept their glucose at a normal level. The next morning, they were retested on the word associations from the night before.

What did the researchers find?

When retested on the same word pairs in the morning, everyone, whether or not they had diabetes, only remembered one more word pair after the night when their blood glucose dropped. The morning after blood glucose levels stayed normal, they remembered up to 3 more word pairs. This showed that when blood glucose levels were dropped overnight, the memory stored less from the day before.

What are the limitations of the study?

Thirty-two participants were enough to prove that a period of low blood glucose during the night does affect the memory, but researchers should test a larger group to support and understand these results.

What are the implications of the study?

New findings in diabetes research show that high blood glucose over time leads to mild brain disorders. This study suggests that low blood glucose could also be a cause for these problems since long periods of low blood glucose at night disrupt the normal, ongoing memory process. Doctors should examine sleep more carefully as an important time for treatment of type 1 diabetes.

Patients who suspect that they are having low blood glucose levels during sleep should consult their doctor. The doctor may want to adjust their insulin or eating schedule.

FOR MORE INFORMATION

Nighttime and Exercise-Induced Hypoglycemia

Hypoglycemia

Beating the Blood Sugar Blues