Why High on Wakeup?

Guest post from David Mapletoft, Diabetes Educator

Like all things about insulin, blood glucose level and diabetes in general, the reasons why you may go to bed with a perfectly reasonable blood glucose level and wake up higher, are complex. But let’s try and make it understandable in its simplest form.


Commonly referred to (by even the ‘experts’) as sugar – ‘blood sugar level’; ‘how are your sugars’ etc

Glucose enters your blood from the digestion of carbohydrate foods, AND from the liver producing glucose to fuel your body when needed – a 24 hour process.

Your muscles store glucose for when you need to move: glucose is your body’s main fuel.

Muscles & Glucose

You muscles store glucose.

Insulin allows glucose to enter the muscle. Picture this: The MCG (Melbourne Cricket Ground) – a stadium that holds 100,000 people. It has 100 gates that open on game day to allow the crowd to get inside.

Imagine a muscle is like a brick wall: each individual muscle cell represents a brick in the wall (ok, no Pink Floyd jokes).

Imagine that each gate at the MCG represents a ‘gate’ on your cell wall that opens when a piece of insulin opens it.

Each cell is like the MCG – it has thousands of gates on the wall to open and close to allow the glucose to get inside.

When the body is making insulin in normal quantities – we have no diagnosis of diabetes. But sadly, that’s NOT YOU.

So, if a person has any type of diabetes, the pancreas is under-producing insulin. When there is insufficient insulin the ‘gates’ of your cell work inefficiently. This of course has the glucose stuck outside the ‘stadium’ (muscle cell) waiting longer to get inside.

Imagine, game day at the MCG. 100,000 people there for the cricket …. don’t laugh, it used to happen! We have a problem IF half the gates are closed, and the keys are lost. Instead of the crowd moving into the stadium, it takes twice as long due to the closed gates.

Closed gates on your cell wall – it takes longer for the glucose to move from the blood into the cell and ….. therefore a high blood glucose level

The brain is a greedy guts for glucose.

The brain is so very specialised, and requires such a large amount of glucose, its calls absorb glucose without the need for insulin to be present.  When you are not eating the brain still needs glucose. This glucose is supplied by the liver, which makes glucose and releases it into the blood 24/7 (other hormones – natural chemicals in your body – also play a part in the blood glucose level – but that waaaaaay toooo complex for now).

But I Didn’t Eat!

So, when you wake up in the morning and your blood glucose level is higher than when you went to bed……..is is not because you ‘sleep walked’ your way to the fridge and ate that leftover pasta / yoghurt / pavlova etc……it’s because your body is not making enough insulin to process the glucose that was released by your liver to fuel your brain and your muscles and your organs (such as your heart)……. OR…….your bedtime injection of insulin was insufficient….. OR…..you had a hypo in the middle of the night (and your liver released insulin to feed your brain).

I hope that helps in some way!

David, Diabetes Educator


  1. Sue on December 20, 2014 at 9:32 pm

    I have recently been diagnosed with type 2. I’m not on medication at this stage, but only correcting diet and moving more. However, this has been happening to me… Last night went to bed with sugars at 6.6 after dinner, got up this morning and they were at 7.7. Does this mean I may need to have medication to manage the morning highs? I’ve randomly tested during the day and sugars are within range of what they should be, but the mornings are all skwiff.

    • Helen-Edwards on December 22, 2014 at 8:33 am

      Sue that is not much of a change and close to target. However if you continue to get morning readings over 6 mmol, you may need to start medication. Best bet is to chat with your doctor.:)

    • Imagine_David on December 22, 2014 at 9:41 pm

      Hi Sue,

      Yes, I agree with Helen. blood glucsoe level over 6.0 mols is worth talking to your doctor about. Not essential to do this now, but certainly in the next few weeks. Have you excluded a low blood glucsoe level overnight? To exclude a low blood glucsoe level overnight, you can measure at 2-3 am.

      Having a snack before bed can also sometimes improve your wake up / fasting blood glucsoe level. By having a snack, you reduce the risk of having a low blood glucsoe level overnight. When there is a low blood glucsoe level overnight the body responds by releasing glucose from the liver, and the wake up blood glucsoe level is over target.