How to respond to blood glucose readings

By Chris Eldridge Dietitian and Diabetes Educator

6 minute read

Published 12 August 2026

name

type 1 diabetes type 2 diabetes prediabetes

How to respond to blood glucose readings

One of the hardest parts of managing diabetes is knowing what to do when you see a blood sugar reading.

So, let's make it easier.

If your blood sugar is higher than expected, the first step is to pause.

Don't rush to correct it straight away.

Think about what might be influencing it.

A recent meal, less activity than usual, stress, illness or medication changes can all play a role.

If you're not feeling unwell, simple steps like drinking some water or gentle movement can help support your levels.

Then we can recheck in around one to two hours to see how things are tracking.

But if you are unwell and have a fever, infection or an upset stomach, your blood glucose levels can behave a little bit differently.

It's important to follow your sick day plan from your healthcare team as your usual patterns and responses may change.

If things aren't improving or blood glucose levels remain consistently high or low, check in with your GP or diabetes care team.

If your blood glucose level is below 4, that is usually considered a hypo or low blood sugar.

It's important to treat a hypo straight away by following the plan you've developed with your healthcare team, so for many people this includes treating it quickly with fast acting carbohydrates like glucose tablets, fruit juice or a non diet soft drink.

After treating the hypo, recheck your blood glucose according to your plan and make sure your levels are recovering.

If your blood glucose levels aren't improving or you're experiencing repeated hypos, contact your GP or your diabetes care team for advice.

If a reading doesn't match how you feel, it's a good idea to check again straight away.

A second reading can help confirm what's going on.

And remember, one reading isn't the full picture, it's the patterns over time that matter the most.

You should also reach out to your GP or specialist if you're seeing a repeated high levels or low levels, or if anything seems out of the ordinary for you.

If you feel it's an emergency, seek urgent medical attention.

Remember, you don't have to react to every number.

When you know what to do in the moment, you can feel more confident in managing your diabetes day to day.

See you next time.

Key takeaways

A high or low reading is a signal to pause and check what may be happening.
If you are unwell, follow your sick day action plan and seek advice early if needed.
A hypo is generally a blood glucose level below 4.0 mmol/L and should be treated quickly.

Pause and think about the pattern

One of the hardest parts of diabetes management is knowing what to do with blood glucose readings.

A number can feel personal, but it’s not a mark of success or failure. It’s information about what is happening in your body at that point in time.¹

If a reading is higher than expected, pause and think about what may have influenced it. Recent food, less activity than usual, stress, poor sleep, illness, pain, medication changes or timing of medication can all play a role. One reading rarely tells the whole story.

What to do if your blood glucose levels stay high

If your blood glucose reading is higher than expected and you feel well, follow the plan you have agreed with your diabetes care team. This may include drinking water, doing some gentle movement if it's safe for you, and rechecking your level later. Contact your GP or diabetes care team if your readings stay high, are unusual for you, or you start to feel unwell.²

It's also important to take high readings seriously when you’re sick. Illness can make it harder to keep glucose levels in range because stress hormones can cause the liver to release more glucose into the bloodstream. This can raise blood glucose levels, even if you’re eating less than usual.²

Create and follow a sick day plan

If you’re sick with a fever, infection, gastro or another illness, follow your personalised sick day action plan. It can help to have a sick day action plan and kit ready to use at the earliest sign of illness.²

If you don’t have a sick day plan, ask your GP, diabetes nurse practitioner or diabetes educator to help create one. It should tell you when to check your glucose, when to check ketones if relevant, what to do with food and fluids, how to manage medicines and when to seek urgent medical help.

Act quickly if your blood glucose level is low

A low blood glucose level, also called hypoglycemia or a hypo, needs quick action. For most people with diabetes, this means a blood glucose level below 4.0 mmol/L. Hypos can happen if you use insulin or some other glucose-lowering medicines and treating them promptly can help stop symptoms from getting worse.³

Your healthcare team should help you create a hypo plan, so you know exactly what to do. For many people, this involves taking a fast-acting carbohydrate, such as glucose tablets, glucose gel, regular soft drink or fruit juice, then rechecking blood glucose as advised in their plan.³

Recheck when something does not seem right

If a reading doesn’t match how you feel, wash your hands, check your equipment and test again. A second reading can help confirm what’s happening. If you use a CGM and symptoms don’t match the sensor reading, your healthcare team may advise confirming with a fingerprick reading.³

Seek support if you’re having repeated highs or lows, your readings are outside your usual pattern, or symptoms feel worrying or unusual. Diabetes management should be personalised, and you deserve clear guidance.

Keep your diabetes care team involved. The goal is not to react to every number, but to understand patterns and know what to do when it matters.

Chris Eldridge Dietitian and Diabetes Educator

Chris is a Clinical and Sports Dietitian with a passion for promoting positive health and preventative care.

At Bupa, trust is everything

Our health and wellbeing information is regularly reviewed and maintained by a team of healthcare experts, to ensure its relevancy and accuracy. Everyone's health journey is unique and health outcomes vary from person to person.

This content is not a replacement for personalised and specific medical, healthcare, or other professional advice. If you have concerns about your health, see your doctor or other health professional.