Health & Wellness

What Are the Symptoms of High Blood Sugar?

Blood SugarWhenever the glucose (sugar) level in one’s blood rises high temporarily, this condition is known as hyperglycemia. The opposite condition, low blood sugar, is called hypoglycemia.

Glucose comes from most foods, and the body uses other chemicals to create glucose in the liver and muscles. The blood carries glucose (blood sugar) to all the cells in the body. To carry glucose into the cells as an energy supply, cells need help from insulin. Insulin is a hormone made by the pancreas, an organ near the stomach.

The pancreas releases insulin into the blood, based upon the blood sugar level. Insulin helps move glucose from digested food enter into cells. Sometimes, the body stops making insulin (for example, in type 1 diabetes), or the insulin does not work properly (as in type 2 diabetes). In diabetic patients, glucose does not enter the cells sufficiently, thus staying in the blood and creating high blood sugar levels.

Blood sugar levels can be measured in seconds by using a blood glucose meter, also known as a glucometer. A tiny drop of blood from the finger or forearm is placed on a test strip and inserted into the glucometer. The blood sugar (or glucose) level is displayed digitally within seconds.

Blood glucose levels vary widely throughout the day and night in people with diabetes. Ideally, blood glucose levels range from 90 to 130 mg/dL before meals, and below 180 mg/dL within 1 to 2 hours after a meal. Adolescents and adults with diabetes strive to keep their blood sugar levels within a controlled range, usually 80-150 mg/dL before meals. Doctors and diabetes health educators guide each patient to determine their optimal range of blood glucose control.

When blood sugar levels remain high for several hours, dehydration and more serious complications can develop. Moreover, even mild hyperglycemia (a fasting blood sugar over 109 mg/dL in adolescents/adults or over 100 mg/dL in children before puberty) – when unrecognized or inadequately treated for several years – can damage multiple tissues in the brain, kidneys, and arteries. When hyperglycemia is associated with the presence of ketones in theurine, this state demands immediate medical attention. When blood sugar levels rise and stay high (over 165 mg/dL consistently) for days to weeks, diabetes should be suspected and must be treated.

High blood sugar level fluctations occur daily in people with diabetes. It is important to control blood sugar levels through diet, exercise, and medication (if prescribed), to know the symptoms of elevated blood sugar, and to seek treatment, when necessary.

These are the symptoms of high blood glucose (hyperglycemia). Regular monitoring can help you avoid high and low blood glucose, avoid complications of diabetes, and help control your blood glucose levels.

Increased thirst

High blood glucose can cause excessive thirst. If you are always thirsty and you can’t seem to get enough fluids despite the amount you drink, diabetes may be out of control.


When insulin in the body is insufficient to push glucose into the cells of the body, glucose stays in the blood streams. As a result, your brain detects this and tells you that you need food.

Headaches and difficulty concentrating

Too much glucose in the blood can result in your brain cells not getting enough glucose to function properly.

Blurred vision

High blood glucose can cause eye problems. High levels of blood glucose pull fluid from your tissues, including the lenses of your eyes, making focusing difficult. When diabetes is uncontrolled, blood vessels in the retina are damaged, and new blood vessels form. You may experience mild vision problems, such as dark spots, flashing lights or rings around lights. It can also cause blindness.

Frequent urination

High blood glucose can cause frequent urination, one of the classic symptoms of uncontrolled diabetes. Although it doesn’t always signal uncontrolled diabetes, if you have diabetes and you have to go too often, then your blood glucose control may be poor. As a result of this, you will feel thirsty, no matter how much you try to replenish the fluids that you lose.

Fatigue or tiredness

High blood glucose can cause fatigue. If you are getting regular exercise, being diligent with your medication, aren’t pregnant, or are relatively stress-free, yet you feel tired and sleepy frequently and have difficulty getting through the day, your diabetes may be out of control. This means that your body is storing and using glucose poorly.

Weight Loss

Too much glucose in the blood can result in your body failing to store glucose in cells properly, and start to break down other sources for energy instead, resulting in weight loss.


High blood glucose weakens your body’s immunity and defenses against infection. When your blood glucose levels are persistently high, your body’s natural ability to heal and fight off infections is impaired. You become vulnerable to influenza, bladder and vaginal infections. If you are always fighting infections, your diabetes may be uncontrolled.

Foot Problems

High blood glucose can lead to nerve damage, usually in the extremities and particularly in the feet and lower leg. You may notice tingling and loss of sensation or burning pain in your feet, legs and hands.

Other conditions

Other signs of high blood glucose can include dry mouth, dry or itchy skin, male impotence, vaginal yeast infections, unexplained aches and pains, urinary tract infections, sores that don’t heal very well, excessive infections and genital itching.

Symptoms will vary from person to person, and may be affected by age or sex.

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9 years ago

I am 65, and finally understand all the symptoms of High Blood Sugar. Do you have any information on ringing noise in the ear?

10 years ago

Appeciated the information – eye-opening yet concise .

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