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Managing a hyper

Hyperglycemia happens when levels of blood glucose are too high. We’ll take you through the things you can do to manage and prevent hypers from happening.
Content last reviewed and updated: 09.08.2023

A woman checking a blood glucose meter as part of managing a type 1 diabetes hyper

What is a hyper?

A hyper – short for hyperglycaemia – is where your blood glucose levels go above range, usually over 7 to 10mml/L.

What can cause a hyper?

Hypers happen when you don’t have enough insulin to process the glucose in your blood, so your blood glucose levels become high.

This might happen if you haven’t had enough insulin to match the carbohydrate you have eaten.

There are other factors that can make your blood glucose levels higher than usual, so hypers can also be triggered by things like stress, illness and even growth spurts.

Signs and symptoms of hyperglycaemia

Symptoms of hyperglycaemia usually develop over the course of a few days or weeks. They are similar to the symptoms most people have when they are first diagnosed, because in both cases there is not enough insulin to bring blood glucose levels down.

Symptoms of hyperglycaemia usually include:

  • Feeling thirsty and having a dry mouth
  • Need to urinate frequently
  • Having blurred vision
  • Feeling tired
  • Losing weight
  • Experiencing recurrent infections such as bladder infections (cystitis), skin infections or thrush
  • Stomach ache
  • Nausea and/or vomiting
  • Fruity-smelling breath

Sometimes, there might not be any symptoms until blood glucose is very high, which is why regular blood glucose monitoring is important.

Like hypoglycaemia, ‘hypers’ are a fact of life for people with type 1 diabetes – it’s pretty difficult to keep your blood glucose within range all the time. A lot of the time, hypers happen when there isn’t enough insulin to match the amount of carbohydrate eaten, however they can also be triggered by stress, illness and even growth spurts.

A hyper doesn’t carry the same immediate risk as a hypo as it won’t make you immediately feel really unwell or to lose consciousness. However, frequent high blood glucose can increase the risks of developing complications of type 1 diabetes, so it’s important to minimise this as much as possible. It can also make you feel pretty unwell if you are hyper for too long.

Are hypers bad?

A hyper doesn’t usually carry the same immediate risk as a hypo and won’t make you immediately feel unwell. However, over time they can cause complications and even be life-threatening.

Diabetic ketoacidosis

When levels of blood glucose go too high too quickly, they can lead to diabetic ketoacidosis (DKA). DKA is serious and can be life-threatening, but it is preventable by effectively managing hypers.


Having frequent high blood glucose levels can increase the risk of developing type 1 complications. For that reason, it’s good to manage your blood glucose levels so you spend as much time within the target blood glucose range as possible (known as time in range).

How do you treat and manage hyperglycaemia?

If you’re getting consistently high blood glucose levels, talk to your Diabetes Healthcare Team. It may be that you need to change your basal or bolus insulin doses.

There are things you can do to help prevent high blood glucose levels or help you and your Diabetes Healthcare Team see what’s going on and what you can do to manage it.

Regular glucose monitoring

Regularly checking your glucose levels with a blood glucose meter, continuous glucose monitor (CGM) or flash glucose monitor will help you see if your levels are going too high.

Using technology like CGM or flash, gives you lots of data about what your blood glucose levels are doing over periods of time – information you can share with your Diabetes Healthcare Team.

Remember that your glucose levels can be affected by things aside from food, such as stress or illness. If there’s something going on that might be causing your levels to run high – like exam stress or a sickness bug – you will need to check your glucose levels more often.

Checking for ketones

When your body doesn’t have enough insulin to turn glucose into energy, it starts breaking down fat instead. This breakdown of fat creates ketones. Having ketones shows that you may be at risk of DKA. You can use a ketone monitor to check if you have any ketones in your blood.

Speak to your Diabetes Healthcare Team if you have concerns about ketones.

Matching your insulin dose to what you eat

Working out how much insulin you need to cover the carbohydrate you’re eating can be difficult, and nobody gets it right every time. There are a range of tools that can help you with this:

Type 1 diabetes education courses

There are free education courses you can attend to learn more about carb counting and dosing insulin. Read more about what courses are available and how to access them. You can also read about the DAFNE course on the dedicated NHS website for DAFNE.

Insulin pumps

If you use an insulin pump you tell it how many carbs you’re eating and it will calculate the insulin dosage for you which can help you dose more accurately.

Type 1 diabetes apps

There are apps that help you count carbs more accurately so that you can work out how much insulin you need to take. Find out more about what apps are available and how they can help.

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