Dawn phenomenon is one common explanation
In the early morning, hormones including cortisol and growth hormone signal the liver to release glucose so the body has energy to wake up. The American Diabetes Association describes this as the dawn phenomenon. In people with diabetes, insulin may not be sufficient to counter that rise.
Other explanations are possible
- Long-acting insulin or other medication effects may not cover the full overnight period.
- A late meal or bedtime snack can keep glucose elevated into the morning.
- Illness, stress and poor sleep can alter the pattern.
- Nighttime lows and rebound patterns are more complicated and should be interpreted with a clinician rather than guessed from a single morning reading.
What to track before changing anything
If your clinician has asked you to monitor glucose, a bedtime reading, an overnight reading or CGM trend, and a waking reading can help distinguish patterns. Medication changes can create hypoglycemia risk, so use the data to support a clinical conversation rather than self-adjusting treatment.
Morning glucose is an outcome. The safest next step is to identify the overnight pattern before deciding what should change.
Sources & verification
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