Why Blood Sugar is Highest in the Morning & How to Prevent It
Many diabetics struggle with achieving good glycemic control. Some people
struggle in particular with fasting blood glucose
levels, the reading
taken first thing in the morning before consuming any calories. Naturally, it would seem
that blood sugar should be lowest in the morning because you haven't had anything to eat in
so long. That's why it can be so confusing when
blood sugar is highest in the morning
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Reasons Why Fasting Blood Sugar Can Be High
- The Dawn Phenomenon. In the hours just after going to bed -
typically midnight to around 3:00am - our bodies don't need a lot of
insulin. Medications taken before bedtime will cause a drop in blood
sugar during this time.
But as our bodies begin to get ready for a new
day, they release stored glucose as well as hormones like cortisol and
growth hormones. These hormones counteract the effects of insulin - they
cause a rise in blood sugar levels instead of dropping them. The
combination of the release of stored glucose, the release of hormones,
and the bedtime dose of insulin wearing off results in a rise in blood
So when you wake up in the morning, your blood sugar is
high. Most people don't realize this is happening and only find out
when they wake up and take a blood sugar reading.
- Rebound Hyperglycemia (The Somogyi Effect).
Rebound hyperglycemia is caused by poor diabetes management, rather than natural
changes in the body during sleep (like the Dawn Phenomenon).
High morning blood sugar can be caused by taking too large a dose of insulin
at bedtime, for example, or eating too small of a bedtime snack. This causes
blood sugar levels to drop too low, triggering your body to release hormones
to counteract it and bring blood sugar levels back up.
Another way high blood sugar can happen is if the bedtime insulin dose is
too small. Without sufficient insulin, blood sugar levels will remain high.
Figuring Out the Cause
Before figuring out what can be done about high blood sugar in the morning,
you need to know what's causing t. Your doctor may ask you to check your blood
sugar early, typically between 2:00am and 3:00am, for several nights in a row.
If there is a consistently a low reading, then it's likely rebound
If the readings are consistently normal or high, then it's more likely to be the
Trying to Achieve a Normal Fasting Blood Glucose
Discuss with your doctor how to manage high morning blood sugar. Options can include:
- Changing what you eat or how much you eat at your bedtime snack.
If you're not currently eating carbs
at night, you may need to have a little. If you are currently eating carbohydrates,
protein and/or fat may be needed instead. You may need to eat a little more to
prevent your blood sugar from dipping too low overnight while you fast.
- Aim for a lower blood glucose reading before bedtime.
That might mean you need to adjust what you eat for dinner, such as having fewer
carbohydrates or eating a smaller meal.
- Adjust the time you take your bedtime insulin, adjust the dosage,
or change the type of insulin you're taking. The morning insulin
dose may also need adjusting.
- Exercise in the evening.
is a great regulator of blood sugar levels, and the effects can last for hours after you stop.
Be sure to keep good records of your blood sugar readings,
along with notes about diet, exercise, medication, etc. so that you can
see what's working and what is not. Your doctor or diabetes educator
can advise you on what changes to make to your
to try to prevent the issue where blood sugar is highest in the morning.
It can take some experimentation and time but it can usually be resolved.
The information on this website is based on our own research and personal experience,
and is not a substitute for medical advice. Questions about your health and individual
situation should be directed to your doctor.