What Is High Blood Sugar (Hyperglycemia)?

High blood sugar (hyperglycemia) occurs when high levels of glucose (sugar) are in the blood.
High blood sugar affects people with type 1 and type 2 diabetes, conditions in which the body has too little insulin or when the body doesn't use insulin properly.
Normal blood sugar levels differ depending on a person’s age and other health conditions.
For adults who have type 1 or type 2 diabetes, and children who have type 1 diabetes, normal blood sugar ranges are:
- Fasting/upon waking and before meals: 80 to 130 mg/dL
- After meals/before bed: Less than 180 mg/dL
High blood sugar (hyperglycemia) is defined as:
- Fasting/upon waking and before meals: above 130mg/dL
- After meals/before bed: above 180mg/dL
What Are Symptoms of High Blood Sugar (Hyperglycemia)?
When blood sugar levels are high, most people will feel thirsty and feel a need to urinate more often.
Symptoms of high blood sugar (hyperglycemia) include:
- Increased thirst
- Frequent urination
- Increased hunger
- Headache
- Blurred vision
- Fatigue
- Dry mouth
- Weight loss
- Fatigue
- Dizziness
What Causes High Blood Sugar (Hyperglycemia)?
Causes of high blood sugar (hyperglycemia) include:
- Not taking enough insulin (type 1 diabetes)
- Insulin is not working as effectively as it should (type 2 diabetes)
- Eating more than planned
- Exercising less than planned
- Stress, such as due to:
- The dawn phenomenon (a surge of hormones the body produces daily around 4:00 a.m. to 5:00 a.m.)
Risk factors for developing high blood sugar include:
- Being overweight
- Unhealthy diet
- Physical inactivity
- Genetics
- Age
- High blood pressure (hypertension)
- High cholesterol
- History of heart disease
How Is High Blood Sugar (Hyperglycemia) Diagnosed?
High blood sugar (hyperglycemia) is diagnosed with the following tests:
- Blood tests
- Fasting blood sugar
- Hemoglobin A1C test
- Fructosamine test
- Use of glucose monitor
- Oral glucose tolerance test
What Is the Treatment for High Blood Sugar (Hyperglycemia)?
High blood sugar (hyperglycemia) can often be treated by the patient with lifestyle measures.
- Exercise
- Quit smoking
- Adjust the amount of insulin used or the timing of when it’s taken (consult your doctor before making any changes to your regimen)
- Surgery, for cases that do not respond to medications
- Bariatric surgery to promote weight loss in obese patients
- Artificial pancreas, to replace the use of insulin injections and pumps and the need for manual testing of glucose levels
What Are Complications of High Blood Sugar (Hyperglycemia)?
If high blood sugar (hyperglycemia) is not treated, the main complication is ketoacidosis (diabetic coma).
Ketoacidosis is life-threatening and needs immediate medical treatment. Symptoms of ketoacidosis include:
How Do You Prevent High Blood Sugar (Hyperglycemia)?
Manage your diabetes and learn to detect high blood sugar (hyperglycemia) so it can be treated early, before it gets worse.
Keep blood sugar levels in check by:
- Eating a healthy diet
- Tracking food, drink, and exercise
- Eating at regular times, and not skipping meals
- Maintaining a healthy weight
- Controlling food portions
- Tracking blood sugar levels if you are diabetic to see what makes them go up or down
- Getting regular exercise