Managing blood glucose levels

What are blood glucose levels?

Your blood glucose level is the amount of glucose (sugar) in your blood. The amount of glucose goes up and down depending on many factors, mainly what you eat and how much glucose you burn off through movement and exercise.

In people who don’t have type 1 diabetes, the body makes insulin to make sure the amount of glucose in the blood doesn’t go too high. If you have type 1 diabetes, the body doesn’t do this, so you have to monitor your blood glucose levels and make adjustments, either by eating glucose to bring it up or taking insulin to bring it down.

What are blood glucose levels measured in?

Blood glucose levels are measured in units called mmol/L (millimoles per litre). In the US, blood glucose levels are measured in mg/dl (milligrams per deciliter). If you read about blood glucose readings that seem very high, like 140 or 220, divide them by 18 to get the mmol/L.

Why is it important to manage your blood glucose levels?

The amount of time you spend within the targets you’ve been given is called time in range. Spending as much time in range as possible is good because it prevents your blood glucose levels going too high which, over time, can lead to complications. In extreme circumstances, very high blood glucose levels can lead to life-threatening diabetic ketoacidosis (DKA). It’s also important to stop blood glucose levels going too low because they can lead to hypos which can be dangerous if they’re not treated quickly.

What affects blood glucose levels?

Blood glucose levels are affected by many factors. Although eating carbohydrates and physical activity are two of the main factors, your levels can also be affected by other things like being hot, cold, ill, stressed, taking other medications or hormonal changes like having your period or going through adolescence or menopause. That’s why it’s important to check them regularly.

How do I check my blood glucose levels?

There are different ways of checking your glucose levels, depending on what works best for you.

You can do finger prick tests with a blood glucose meter. A blood glucose meter tests your capillary blood, which gives you the most accurate blood glucose reading.

Continuous glucose monitors (CGM) send constant readings of your glucose levels to a handset or your mobile phone. There is also flash technology, where you scan a sensor attached to your upper arm with a handset or mobile phone to take a reading.

CGM and flash measure interstitial fluid, which is the fluid between your blood vessels and cells. This is a good measure of your glucose levels, but you’ll sometimes need to use a blood glucose meter to check your capillary blood before taking action, like treating a hypo.

What should my blood glucose levels be?

Nobody expects you to get perfect blood glucose levels all the time. There will be things that will affect your levels that you can’t control, like heatwaves in summer or getting a cold.

Read more about what the target blood glucose levels are.

What to do if your blood sugar is running high/low?

If your blood glucose is running high, you need to take some insulin to bring it down. There are different ways to take insulin. You can inject insulin with a pen or smart pen or use an insulin pump.

If your blood glucose levels are low and you’re having a hypo, you should eat some carbohydrate to bring these levels back up.

Find out more about what to do if you’re having a hypo.

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