High blood glucose can be caused by many things. Knowing the most common causes can help you manage your blood glucose and avoid problems.

Common causes of high blood glucose

Food choices

Eating foods high in carbohydrates, especially refined sugars and simple carbohydrates (known as processed, high GI foods), can lead to rapid spikes in your blood glucose levels. Foods such as sugary snacks, sweetened beverages, white bread, jasmine rice, and pastries are common culprits.

fact-sheet-carbohydrate-counting.pdf (ndss.com.au)

The glycemic index fact sheet (ndss.com.au)

Not enough insulin

When you have diabetes, your body is either producing less insulin and/or your body is resistant to insulin (type 2 diabetes), or your body produces no insulin at all (type 1 diabetes). A lack of insulin can stop glucose from entering body cells properly and in time, so the glucose stays in your blood stream, and your blood  glucose levels rise.

Not enough physical activity

Lack of activity can reduce your body’s ability to use glucose effectively. This can lead to higher blood glucose levels. When you move more your insulin works better.

Stress

Stress triggers the release of hormones such as cortisol and adrenaline (stress hormones), which can cause blood glucose levels to rise. Chronic stress can contribute to long-term blood glucose imbalances.

Medications

Certain medications, such as corticosteroids, some antidepressants, and certain asthma medications, can raise blood glucose levels as a side effect.

Illness or infection

During illness or infection, your body releases stress hormones to fight the illness. This can raise blood glucose levels.

What are the health effects of high blood glucose levels

Short-term effects

High blood glucose can cause symptoms such as increased thirst, frequent urination, fatigue, blurred vision, and headaches. If very high, it can lead to electrolyte imbalance, causing dehydration and/or Hyper Osmolar Hyperglycemic State (HSS) in people with type 2 diabetes and diabetic ketoacidosis (DKA), a life-threatening condition, in people with type 1 diabetes.

Long-term effects

Over time, high blood glucose can damage blood vessels. This can cause heart disease, nerve damage, kidney problems, eye damage, and more infections.

Things you can do to avoid glucose spikes

Monitor blood glucose levels

Check your blood glucose regularly if advised by your doctor or diabetes educator.

Balanced diet

Eat whole grains, legumes, fruits, and vegetables, less processed foods and low GI carbohydrates. Include lean proteins and healthy fats. Ask your doctor to refer you to a dietitian.

Portion control

Eat smaller, more frequent meals to avoid large spikes.

Food and Nutrition Resources | NDSS

Exercise regularly

Sitting less and building muscle are important. Activities like walking, cycling, or swimming can help you to keep you blood glucose in your target range. If you are not sure about your target range, speak with your diabetes educator.

Physical Activity | NDSS

Take your medications

Follow your doctor’s advice for any medicines you need, including insulin.

Manage stress

Practice deep breathing, meditation, or hobbies to reduce stress.

Emotional and Mental Health | NDSS

Stay hydrated

Drink plenty of water to prevent dehydration. Drinking water won’t lower your blood glucose levels, but it can help you manage your glucose levels. Drinking enough water is healthy, with research linking it to a reduced risk of high blood glucose and effective for flushing waste out your kidneys.

Regular check-ups

Visit your doctor regularly to monitor your health and adjust your treatment as needed. Knowing if you are outside your target blood glucose range could help you to make changes. See your doctor for regular checks.

Annual cycle of care (ndss.com.au)

By understanding the causes of high blood glucose levels and ways to manage them, you may be able to improve your diabetes self-care and avoid complications.

For more help, follow the links in the article or call the NDSS helpline at 1800 637 700 and ask to speak with a Credentialled Diabetes Educator (CDE), Accredited Practising Dietitian or Accredited Exercise Physiologist.

By Vania Khoury, Credentialled Diabetes Educator and Registered Nurse