Nocturnal hypoglycemia decreases awakening response in adults with type 2 diabetes
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Overnight hypoglycemia in adults with type 2 diabetes leads to a decreased awakening response in the hours after the event, affecting the person’s ability to respond with an adequate intake of carbohydrates, according to research in Diabetes Care.
Poul Jennum, MD, DMSc, of the Danish Center for Sleep Medicine at Copenhagen University Hospital in Glostrup, Denmark, and colleagues screened 42 adults with type 2 diabetes (18 men; mean age, 55 years; mean BMI, 29.6 kg/m²; duration of diabetes, 5.4 years) for study participation; 20 completed two overnight sleep sessions in a lab setting and were evaluated in the study. During one overnight visit, researchers induced hypoglycemia with a hyperinsulinemic clamp; after participants reached sleep stage N2, researchers turned off glucose infusion until the plasma glucose target of 2.7 mmol/L to 2.8 mmol/L was reached and maintained for 15 minutes. The participants were then brought back into normal glycemic range for the remainder of the night. During a separate visit, plasma glucose was maintained in the normoglycemic range for the duration of the session; participants were assigned to the two sessions in random order.
Poul Jennum
When compared with the normoglycemic night, the rate of awakenings fell 27% between hours 4 and 8 on the hypoglycemic night; awakenings were 20% fewer during hours 0 to 8. Participants also slept longer during the hypoglycemic night (366 minutes vs. 349 minutes), and researchers measured significantly higher hormonal responses to hypoglycemia (adrenaline, growth hormone and cortisol) on the hypoglycemic night.
“It is noteworthy that a reduced awakening response was observed in this population, despite the relatively recent diagnosis and that the subjects were insulin naive,” the researchers wrote. “For patients experiencing life-threatening physiological changes during sleep, the arousal response can be critical for survival. In contrast, the reduced awakening response seen following nocturnal hypoglycemia in this study could potentially be harmful by rendering patients unable to compensate behaviorally, thereby prolonging and worsening the hypoglycemic episode.”
“The study adds further understanding of the problems with sleep-related hypoglycemia and its relation to daytime impairment and comorbidity,” Jennum told Endocrine Today. “We need to explore the central regulatory mechanism involved in hypoglycemia during sleep.” – by Regina Schaffer
D isclosure: Novo Nordisk sponsored this study, and three of the study researchers report being employees and shareholders of Novo Nordisk. Jennum reports no relevant financial disclosures. Please see the full study for a list of other relevant financial disclosures.