There is a lot of information out there about what to do when blood glucose levels (BGLs) are low, but what about when they are high? Hyperglycaemia, or high blood glucose levels, can affect people with all types of diabetes, making you feel more tired, headachy, irritable or thirsty.

Many different factors can make your blood glucose levels higher than normal. Figuring out the underlying cause is the first step to knowing how to bring them back down. We’ve picked out the top reasons why your blood glucose levels might be high:

1. Carbohydrates like bread, potato, fruit and milk products are all broken down into glucose and directly raise blood glucose levels. Having a bigger meal or more carbohydrate than usual can push glucose levels up.
2. Physical activity is great for using up glucose from the blood. Being less active than usual can mean the glucose is stuck in the blood, making glucose higher than normal. Intense exercise can initially make glucose levels higher but the muscles will soon use it up for energy.
3. Medications for diabetes, including tablets and insulin, are all designed to lower glucose levels, so missing a dose or taking less than usual will usually result in higher blood glucose levels. Some other medications, such as steroids, make the body more insulin resistant and so raise glucose levels.
4. Stress tells the body to be on high alert and get ready for action. The body responds by making the heart beat faster, the breathing rate speed up and dumping extra glucose in the blood for energy.
5. Illness or infection causes the body to produce extra hormones to help heal the body. However these hormones temporarily prevent insulin from working effectively and can make blood glucose levels higher than usual.
6. Hot weather doesn’t directly affect glucose levels but makes us sweat more, making it easier to become dehydrated. Dehydration makes the blood thicker and the glucose concentration rise.
7. Diabetes is progressive meaning that cells in the pancreas wear out over time and are not able to make as much insulin. This may lead to higher blood glucose levels and signal the need for changes to your diabetes management plan.

Having a one-off, high blood glucose level is not going to dramatically increase the risk of diabetes complications.  In people with type 2 diabetes, their body is still able to make some insulin, so the glucose level usually comes back down within a few days once the underlying issue has been resolved.

In the meantime, aim to get plenty of rest, drink plenty of fluids and do some light exercise such as a walk around the block, if you’re feeling well enough. If you’re sick or treating an infection, talk to your GP or pharmacist about options to treat the problem and alleviate symptoms. If you’re feeling stressed, depressed or anxious, take some time out for yourself to do something you enjoy – maybe a massage or catch up with a friend. Remember a problem shared is a problem halved – try talking to a friend, family member or professional counsellor or psychologist.

If blood glucose levels are getting very high or becoming symptomatic or have not returned to normal within one to two weeks, talk to your GP or diabetes care team.