T1D Info


Healthcare Professionals

About Us

Managing your diabetes when you are sick

Edited: 18.04.2024

Anne-Charlotte Ficheroulle

Pharmacist, Digital Innovation Manager, A4D

1. What happens with diabetes control when you are sick?

Like everyone you may get sick from time to time. However, because the effects of illness on the body can raise or lower your blood glucose levels, a few extra steps are needed to keep blood glucose levels under control. Managing your diabetes when you are sick is an important thing to learn.

Blood glucose levels can be very unpredictable on sick days. You can’t know exactly how the illness will affect your diabetes control. So it’s important to check your blood glucose levels more often on sick days and adjust insulin doses as needed.

When you have a cold, flu, or any other illness with or without fever, your body needs extra energy to fight off the germs, and it might interfere with the action of insulin you inject.

Your cells may need more insulin to work, or less insulin. Eating, drinking, and taking insulin are extremely important when you are ill.

If the cells do not get enough energy, or if there isn’t enough insulin to help the glucose get into your cells, your body breaks down its own stores (fat and muscle) to provide this energy. This process produces waste products called ketones which are dangerous in high quantities.

If high blood glucose levels are not treated, ketones will develop and you could become very sick with diabetic ketoacidosis (DKA) even without an identifiable illness.

Read more.

2. How can I be prepared?

Knowing how to manage sick days should prevent any major problems and complications.

The goals of sick daycare are to:

  • prevent dehydration

  • prevent ketoacidosis (high levels of sugar and ketones in the blood)

  • prevent hypoglycaemia (low blood glucose levels).

3. How to recognise ketones?

Here are some symptoms to recognise when blood ketones are being produced by the body:

  • Breath that smells fruity

  • High blood glucose levels

  • Going to the toilet a lot

  • Being really thirsty

  • Feeling more tired than usual

  • Stomach pain

  • Changes to their breathing (usually deeper)

  • Confusion

  • Fainting

  • Feeling or being sick

The best way to test ketones is by using blood ketone test strips. Many people do not have blood ketone test strips and the machine available at home. Your local clinic or healthcare centre may be able to do this.

4. What should I do when I am sick?

Please follow these general guidelines during any illness:


  • Insulin dose may need to be increased or decreased, based on blood glucose level and food intake

  • Increase blood glucose monitoring to 3-4 hourly if test strips available

  • If unable to test blood glucose levels at home, admit to a local health facility for regular testing

  • Drink more water. Eat small and frequent meals but in regular meal timing

  • Treat fever

Monitoring for urinary or blood ketones is very important. Additional insulin is usually necessary to control blood glucose levels (unless the illness causes hypoglycaemia).

If you have elevated blood glucose level with no or small ketones:

  • Take 5-10% of total daily dose of insulin as short or rapid-acting insulin and repeat every 2-4 hours

If you have elevated blood glucose level with moderate or large ketones:

  • Take 10-20% of total daily dose of insulin as short or rapid-acting insulin and repeat every 2-4 hours

If you are vomiting, this is a sign of insulin deficiency and diabetic ketoacidosis (DKA). Please call your doctor immediately or go to the local clinic/hospital.

5. What should I do when I am sick?

People with diabetes need to take extra care of their body, especially when they get sick. Being ill can cause blood sugar levels to be more unpredictable, making it more difficult to manage.

This is why it is important to take care of your body by following closely your doctor’s advice in managing your diabetes. It would be best to inform your doctor whenever you get sick, so that they can guide you on how to monitor your blood glucose levels and what you can do to keep it under control.

Managing your diabetes well by taking your medication, eating right, and staying healthy, can go a long way in terms of maintaining a good quality of life.

Take the quiz on sick day management now!

Icon Disclaimer:

You are not alone!

There are many people who have the condition.

on the Type 1 Facebook community.