Insulin

Dawn phenomenon

• BG levels tend to rise in the hours of the morning (usually after 5.00 am) prior to waking. This is called the dawn phenomenon. In non-diabetic individuals the mechanisms include increased nocturnal growth hormone secretion, increased resistance to insulin action and increased hepatic glucose production. These mechanisms are more potent in puberty
• In individuals with type 1 diabetes, fasting hyperglycemia is predominantly caused by waning insulin levels, thus exaggerating the dawn phenomenon. Research studies have not confirmed Somogyi’s idea that the rising BG is due predominantly to counter-regulatory hormones
• Correction of fasting hyperglycemia is likely to require an adjustment of the insulin regimen to provide effective insulin levels throughout the night and the early morning, for example by the use of
  • intermediate-acting insulin later in the evening or at bedtime
  • a longer acting evening insulin
  • insulin pump treatment