Blood glucose, insulin and HbA1c

If you have type 1 diabetes, what is happening in your body? Your body stops making enough insulin and insulin is responsible for moving glucose out of your bloodstream into your cells to give them energy to work, e.g. your muscle cells to contract and your brain cells to ‘think’. It’s important that your blood glucose is well controlled in order for your body to function properly.

High blood glucose

Without insulin, the glucose from your food cannot enter the body cells and builds up in your bloodstream, eventually passing out of the body in your urine. (This is why one of the typical symptoms of diabetes, or uncontrolled diabetes, is ‘sweet urine’ – the glucose level can be measured using urine dipsticks).

High blood glucose, or hyperglycaemia, can be dangerous. When the glucose in your bloodstream is high for a long period of time, it stops the tiny blood vessels, or capillaries, and the nerves around them from working properly. This eventually results in irreversible tissue damage. 

Controlling your blood glucose levels will help you avoid complications like:

heart attack


reduced eyesight, blindness

kidney disease

nerve problems

blocked circulation in the feet

foot infection, which can lead to gangrene

leg amputations

Low blood glucose

Very low blood glucose is also dangerous – your body needs glucose to fuel itself and when blood glucose drops too low, tiredness and loss of energy occurs. You may also feel confused. You’ve probably experienced this before – the faint, shaky feeling you get if you haven’t eaten for a long time.

The medical term for low blood glucose is hypoglycaemia. People with diabetes who are on medications that increase insulin production in the body, or who are on insulin, need to be aware of the signs of hypoglycaemia, or “a hypo”, because sometimes these medications can make it drop too low.

The signs of hypoglycaemia are:

shakiness or feeling weak

sweating, chills and clamminess


rapid/fast heartbeat

light-headedness or dizziness

nervousness, anxiety or irritability

How should you treat a hypo?

If you have a hypo, you should treat it by consuming something sugary, like orange juice or sweets, otherwise you may lose consciousness. It is important to always carry something to help you treat a hypo.  It’s recommended that you consume 15 grams of carbohydrate that is absorbed quickly, such as juice, milk, sweets, or glucose tablets. If you are unsure about what a hypo feels like and how to treat one, please seek advice from your doctor or nurse.

As time goes on, you’ll become more familiar with what high and low blood glucose feels like, and what to do about it.

Blood glucose measurements

You can now see why it’s important to maintain your blood glucose levels within a ‘healthy’ range – how can you achieve this?

Monitoring your blood glucose frequently on a day-to-day basis is the key to good control. Keeping track of the values allows you to adjust your diet or insulin dose appropriately to maintain levels in the correct range.

Blood glucose measurements

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