Languages
The NDSS is administered by Diabetes Australia
brandlogo diabetes australia

Hyperglycaemia and sick days

There will be times when your glucose level goes above your target range. This is called hyperglycaemia. It’s important to be prepared so you know what to do and where to get support if you need it.

What's on this page

Causes of hyperglycaemia

Common reasons for hyperglycaemia include:

  • missing insulin doses
  • being sick from an illness or an infection
  • having surgery or medical procedures
  • feeling very stressed
  • not being as active as you usually are
  • over-treating your low glucose levels (hypoglycaemia or hypos for short).

Some other causes of hyperglycaemia

There are many other reasons why your blood glucose levels may be too high, for example:

  • not having enough insulin for the amount of carbohydrates you’re consuming
  • using insulin that is out of date or has been accidently frozen
  • feeling super excited or stressed
  • reacting to a vaccine
  • other hormones
  • insulin pump or CGM malfunction
  • sometimes you just don’t know why!

Signs and symptoms of hyperglycaemia

When glucose levels are only a little higher than your target range, you may not feel any symptoms. You may only know from checking your glucose levels. If your glucose level continues to rise, you may notice some or all these symptoms.

Passing urine (peeing) more often, especially at night

Feeling very thirsty

Feeling tired and weak

Having headaches

Blurry vision

Losing weight

You may remember these symptoms from the time before you were diagnosed with type 1 diabetes.

Managing hyperglycaemia

If your blood glucose level has only been high for a short time, you know the reason and if you’re feeling well, treatment may not be necessary. Continue to check your blood glucose level. If you’re using a CGM, you can set an alarm to alert you to when the glucose is above your target. This can help you keep track of how you’re going.

Let’s find out what you can do to reduce your risk of hyperglycaemia:

  • Check your glucose level regularly.
  • Choose to use CGM to check your glucose level through the day and night, and set an alarm to alert you when your level goes above your target range.
  • Count your carbs to help you work out insulin dose for your meals (bolus insulin).
  • Take your insulin and other medication as prescribed by your doctor or diabetes nurse practitioner.
  • Look for patterns when your glucose level is above your target.
  • Manage your sleep and stress.
  • Have a sick day action plan and start using it as soon as you’re feeling unwell.

Find out more

If you are using a CGM, you may need to confirm your glucose level using a finger prick blood glucose check.

What to do if you have hyperglycaemia

Determine the cause
It may be in response to what you’ve been doing, what you’ve eaten, or how you’re feeling. If your glucose levels continue to stay above your target, you may need extra insulin. This is called a ‘correction’ dose.

Ask for help
Ask your doctor or diabetes nurse practitioner about how and when to use insulin correction doses and ask them to give you a written sick day action plan.

Let a friend or family member know when you are unwell
Tell them about your sick day action plan in case you need help. If possible, have someone stay with you or check on you frequently.

When to seek medical attention

In most situations you will be able to manage hyperglycaemia at home. Start using your sick day action plan as a guide. Ask your family members or friends, and your diabetes health professionals for support if you need it.

If there is no improvement, you’re at risk of diabetic ketoacidosis (or DKA for short). DKA is serious if it isn’t treated fast. It’s a medical emergency and you’ll need to go to hospital for treatment. You know your own body and if you feel your symptoms are getting worse, seek emergency medical care.

Some of the warning signs

Your blood glucose level is not improving or the ketones in your blood or urine are increasing.

You’re getting drowsy and confused, have signs of dehydration such as a headache, or have severe tummy pain or difficulty breathing.

You’ve been vomiting more than 2 hours or can’t drink any fluids.

The symptoms of your illness aren’t improving with medication such as a high temperature or headache.

Reducing the risk of diabetic ketoacidosis

When you have type 1 diabetes and have hyperglycaemia, you’re at risk of DKA. DKA happens when there isn’t enough insulin for the body to use glucose as energy. The body uses fat for energy instead. This results in a build-up of acids in the blood called ketones. If left untreated, the build up of ketones can lead to DKA.

When you have type 1 diabetes, you need to know the signs of DKA and when to seek emergency care. Be alert for these serious signs and symptoms and start your sick day action plan immediately.

Know the signs and symptoms of DKA

Having fruity-smelling breath

Having nausea, or vomiting and diarrhoea

Having tummy pains

Breathing quickly and deeply, or having trouble catching your breath

Dehydration such as feeling very thirsty, having a dry mouth, or not peeing much

Feeling sleepy, weak or confused

Ketones

When to check for ketones

Always check for ketones if:
  • your blood glucose level is 15 mmol/L or above
  • you’re sick or feel unwell, even if your blood glucose level is less than
    15 mmol/L.

How to check for ketones

Your diabetes health professional will help you decide the best way for you to check for:

  • blood ketones using a compatible blood glucose meter and blood ketone strips OR
  • urine ketones using urine ketone strips (subsidised through the NDSS).

Drinking water will help reduce the risk of dehydration. Continue to check your blood glucose levels and ketones every 2-4 hours.

If the ketones in your bloodstream are 0.6 to 1.5 mmol/L (or moderate to high in your urine) start following your sick day action plan. Start straight away to avoid emergency problems like DKA. DKA is best treated with fluids and insulin, usually in hospital.​

Exercise tips

glucose
glucose-stick
If your blood glucose levels are higher than 15 mmol/L, make sure you check for ketones before you exercise.

It can be dangerous to exercise when blood glucose levels are high and/or you have ketones in your blood or urine. This means you don’t have enough insulin in your bloodstream for your muscles to use glucose for energy. It can increase your risk of DKA.

Managing sick days

Preparing for sick days

Being unwell can make it more challenging to keep blood glucose levels in your target range. This is because of the stress hormones your body releases when you’re sick. Stress hormones increase the amount of glucose the liver releases into the bloodstream.

This can make it difficult for your usual dose of insulin to keep your blood glucose levels in your target range. If you’re sick and have a high blood glucose level, you’re at risk of severe dehydration and DKA.

DKA is a medical emergency and if left untreated it can be life-threatening.

Be prepared and reduce your risks of DKA

  • Ask your diabetes health professionals to help you make a written diabetes sick day action plan.
  • Your doctor, diabetes nurse practitioner or diabetes educator will work with you to develop your personalised plan.
  • Work with your diabetes health professionals to update your plan every 1-2 years or more often if there are changes to how you manage your diabetes.
  • Keep your plan in an easily accessible place. 
  • Let your family or those who support you know where you keep your plan.

Find out more

Important things to do every time you feel sick

Follow your sick day action plan

A sick day action plan is step-by-step written instructions on how to manage your diabetes when you’re unwell. Start following your plan as soon as you feel unwell, your blood glucose reaches the level that is written in your plan (or is greater than 15 mmol/L) – even if you feel well, or have ketones in your bloodstream of 0.6 to 1.5 mmol/L (or moderate to high in your urine).
let-someone-know

Let someone know you are unwell

Let a friend or family member know that you’re unwell. Tell them about your sick day action plan in case you need help. If possible, have someone stay with you or check on you frequently.
check-your-blood-glucose-level

Check your glucose levels more often

Check your glucose levels every 2 hours or more often according to your sick day action plan. If you’re using a CGM, you may need to confirm the result with a finger prick blood glucose check. Remember there’s lag time between blood glucose levels measured by a finger prick check and CGM glucose levels. Your blood glucose level and sick day action plan will help you to work out if you need to change your insulin doses.

check-for-ketone

Check for ketones

You should check for ketones every 2-4 hours when you’re unwell. The most accurate way to check for ketones is to use a blood glucose meter that also checks for blood ketones.
change-your-insulin-dose

Change your insulin dose if needed

Your body usually needs extra insulin when you’re unwell, even when you are not eating much.Your sick day action plan can help you work out if you need to take extra insulin. It can also help you decide how much extra insulin you should take.
keep-drinking

Keep drinking and (if possible) eating

It’s very important to keep up your fluid intake. This will reduce your risk of becoming dehydrated. It’s also very important to keep up your carb intake if needed to reduce your risk of hypos. Your sick day action plan should have instruction about when to choose carb-free fluids and when to have fluids containing carbs. Aim for at least 1 cup of fluid every hour.

ask-for-help

Ask for help

If you need advice about your insulin doses, taking other medications when you’re unwell, or have questions about your sick day action plan, contact your doctor, diabetes nurse practitioner or diabetes educator.

seek-urgent-emergency-care

Seek urgent emergency care

It’s a medical emergency and you should go to the hospital emergency department or call 000 immediately if you: 

  • have blood ketones of 3.0mmol/L or more 
  • are vomiting a lot 
  • don’t have anyone that can help you 

Ask someone to drive you to the hospital or call 000 for an ambulance.  

Your sick day kit

You will probably already have a first aid kit at home that you can use to make your diabetes sick day kit. To help manage your diabetes when you are unwell, here’s some things you should have in the kit.

What to pack

Top tip

You can easily get all these items from the supermarket and a pharmacy.

Last updated: May 2025

Contact us

Footer Logo
logo diabetes australia
Facebook-f Twitter
Diabetes Australia acknowledges the Traditional Custodians of the lands on which we work and live, and we pay our respects to all Elders past, present and future.
Diabetes Australia acknowledges Aboriginal and Torres Strait Islander peoples as the Traditional Owners and Custodians of this Country. We recognise their connection to land, waters, winds and culture. We pay the upmost respect to them, their cultures and to their Elders, past and present. We are committed to improving health outcomes for all Aboriginal and Torres Strait Islander people affected by diabetes and those at risk.
Learn about the artwork