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The dawn phenomenon, also called the dawn effect, is the term used to describe an abnormal early-morning increase in blood sugar (glucose) — usually between 2 a.m. and 8 a.m. — in people with diabetes.
Some researchers believe the natural overnight release of the so-called counter-regulatory hormones — including growth hormone, cortisol, glucagon and epinephrine — increases insulin resistance, causing blood sugar to rise. High morning blood sugar may also be caused by insufficient insulin the night before, insufficient anti-diabetic medication dosages or carbohydrate snack consumption at bedtime.
If you have persistently elevated blood sugar in the morning, checking your blood sugar once during the night — around 2 a.m. or 3 a.m. — for several nights in a row will help you and your doctor determine if you have the dawn phenomenon or if there's another reason for an elevated morning blood sugar reading.
Your doctor may recommend a number of options to help you prevent or correct high blood sugar levels in the morning:
M. Regina Castro, M.D.
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