Dawn phenomenon refers to -

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 and 8 a.m. -- in people with diabetes. It arises through a combination of the normal circadian rhythm and release of counter-regulatory hormones (growth hormone, coisol, glucagon and epinephrine) during the later pa of the night which increases insulin resistance, causing blood sugar to rise, as well as diminishing levels of overnight insulin. Steps that may help include eating dinner earlier in the evening, avoiding carbohydrate intake at bedtime, doing something active after dinner (such as going for a walk), moving the long-acting insulin from before the evening meal to bedtime, switch to a different medication, use an insulin pump to administer extra insulin during early-morning hours. Reference : page 825 Davidson's Principles and practice of Medicine 22nd edition and page 2412 Harrison's Principles of Internal Medicine 19th edition