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High Blood Sugar Basics

High blood sugar, called hyperglycemia, is one of the defining characteristics of diabetes. When people are diagnosed with diabetes, it means their blood sugar has been high, usually for a long period of time. Over time, high blood sugar can lead to serious long-term health problems. Click here to test your knowledge about blood sugar.

The good news is that scientific studies have proven that control of blood sugar may help delay or even prevent diabetes complications – get started by learning more about the signs and causes of high blood sugar and tips to help prevent its development.

What happens when you have high blood sugar?

  • Insulin is a hormone needed for proper control of blood sugar. In patients with type 2 diabetes, your pancreas does not make enough insulin, and/or the insulin that the pancreas makes does not work the way that it should. As a result, sugar in the blood cannot enter most cells and the liver makes too much sugar, causing blood sugar levels to get too high. The cells in your body are unable to use this sugar for energy and high blood sugar can cause serious long-term health problems.

High blood sugar symptoms

  • When sugar levels become high, you may experience:
    • Dry mouth, thirst
    • Frequent urination
    • Fatigue
    • Blurred vision
    • Headaches
    • Weight loss
    • Frequent infection

    However, some patients with type 2 diabetes may have no symptoms.

What should I do if I have symptoms?

  • If you haven’t been diagnosed with type 2 diabetes, see your diabetes healthcare team (primary care provider, endocrinologist and diabetes educator) for an evaluation
  • If you have diabetes, it’s important to check blood sugar levels regularly to make sure you are within your goal range, take your medication as directed, stay on your meal plan and get regular physical activity
  • Review your latest A1C test results with your diabetes healthcare team
  • Talk to your diabetes healthcare team about your blood sugar goals and how best to keep your blood sugar under control
  • Click here for more information on what to do if your blood sugar levels are too high

What causes high blood sugar?

  • High blood sugar in people with type 2 diabetes can be caused by the following:
    • Not staying on your prescribed meal plan
    • Insufficient physical activity
    • Not taking your prescribed medicine
    • Stress from any illness, including cold or flu
    • Emotional stress, such as family conflicts or school or dating problems
  • High blood sugar usually occurs over a period of days
  • Over time, your body may make less insulin, which can contribute to high blood sugar. Your treatment plan may need to be adjusted to keep your blood sugar under control. Talk with your diabetes healthcare team about changes to your meal plan and physical activity, and whether adjustments to the medication you take may be necessary

Consequences of high blood sugar

  • Short-term complications of high blood sugar can affect daily life, and may include fatigue, inability to concentrate and blurred vision. In severe cases, ketoacidosis (diabetic coma) can occur and requires emergency treatment
  • Long-term consequences of untreated diabetes can have devastating health effects and include:
    • Heart disease
      Heart disease and stroke are the number one cause of death and disability in people with type 2 diabetes
    • Kidney disease
      Diabetes is the leading cause of kidney failure
    • Nerve and blood vessel damage
      About half of all people with diabetes have some form of nerve damage
    • Blindness
      People with diabetes are at an increased risk for eye complications that can lead to blindness
    • Gum disease
      People with diabetes – especially those with poor blood sugar control – are at a higher risk for gum problems

What can I do to control my high blood sugar?

  • To help control high blood sugar, it’s important to set goals with your diabetes healthcare team for weight, physical activity, blood sugar levels and A1C level
  • Stay as close as you can to your schedule of eating, physical activity, and medication
  • Check your blood sugar levels regularly and share your tracking records with your diabetes healthcare team (primary care provider, endocrinologist and diabetes educator).
Fast 5 Questions to Ask Your Doctor

Make your next conversation with your diabetes healthcare team count by asking these five questions about blood sugar!

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Blood Sugar Checklists

Make sure you're checking off these boxes in addition to checking your blood sugar!

Low Blood Sugar Checklist  High Blood Sugar Checklist

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