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What does high blood sugar mean

Hyperglycemia in diabetes - Symptoms and causes


High blood sugar, also called hyperglycemia, affects people who have diabetes. Several factors can play a role in hyperglycemia in people with diabetes. They include food and physical activity, illness, and medications not related to diabetes. Skipping doses or not taking enough insulin or other medication to lower blood sugar also can lead to hyperglycemia.

It's important to treat hyperglycemia. If it's not treated, hyperglycemia can become severe and cause serious health problems that require emergency care, including a diabetic coma. Hyperglycemia that lasts, even if it's not severe, can lead to health problems that affect the eyes, kidneys, nerves and heart.

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Hyperglycemia usually doesn't cause symptoms until blood sugar (glucose) levels are high — above 180 to 200 milligrams per deciliter (mg/dL), or 10 to 11. 1 millimoles per liter (mmol/L).

Symptoms of hyperglycemia develop slowly over several days or weeks. The longer blood sugar levels stay high, the more serious symptoms may become. But some people who've had type 2 diabetes for a long time may not show any symptoms despite high blood sugar levels.

Early signs and symptoms

Recognizing early symptoms of hyperglycemia can help identify and treat it right away. Watch for:

  • Frequent urination
  • Increased thirst
  • Blurred vision
  • Feeling weak or unusually tired

Later signs and symptoms

If hyperglycemia isn't treated, it can cause toxic acids, called ketones, to build up in the blood and urine. This condition is called ketoacidosis. Symptoms include:

  • Fruity-smelling breath
  • Dry mouth
  • Abdominal pain
  • Nausea and vomiting
  • Shortness of breath
  • Confusion
  • Loss of consciousness

When to see a doctor

Seek immediate help from your care provider or call 911 if:
  • You have ongoing diarrhea or vomiting, and you can't keep any food or fluids down
  • Your blood glucose levels stay above 240 mg/dL (13. 3 mmol/L) and you have symptoms of ketones in your urine
Make an appointment with your health care provider if:
  • You have ongoing diarrhea or vomiting, but you're able to take some foods or drinks
  • You have a fever that lasts more than 24 hours
  • Your blood sugar levels stay above 240 mg/dL (13.3 mmol/L) despite treatment, and you have symptoms of ketoacidosis
  • You have trouble keeping your blood glucose within your target range

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During digestion, the body breaks down carbohydrates from foods — such as bread, rice and pasta — into sugar molecules. One of the sugar molecules is called glucose. It's one of the body's main energy sources. Glucose is absorbed and goes directly into your bloodstream after you eat, but it can't enter the cells of most of the body's tissues without the help of insulin. Insulin is a hormone made by the pancreas.

When the glucose level in the blood rises, the pancreas releases insulin. The insulin unlocks the cells so that glucose can enter. This provides the fuel the cells need to work properly. Extra glucose is stored in the liver and muscles.

This process lowers the amount of glucose in the bloodstream and prevents it from reaching dangerously high levels. As the blood sugar level returns to normal, so does the amount of insulin the pancreas makes.

Diabetes drastically reduces insulin's effects on the body. This may be because your pancreas is unable to produce insulin, as in type 1 diabetes. Or it may be because your body is resistant to the effects of insulin, or it doesn't make enough insulin to keep a normal glucose level, as in type 2 diabetes.

In people who have diabetes, glucose tends to build up in the bloodstream. This condition is called hyperglycemia. It may reach dangerously high levels if it is not treated properly. Insulin and other drugs are used to lower blood sugar levels.

Risk factors

Many factors can contribute to hyperglycemia, including:

  • Not using enough insulin or other diabetes medication
  • Not injecting insulin properly or using expired insulin
  • Not following your diabetes eating plan
  • Being inactive
  • Having an illness or infection
  • Using certain medications, such as steroids or immunosuppressants
  • Being injured or having surgery
  • Experiencing emotional stress, such as family problems or workplace issues

Illness or stress can trigger hyperglycemia. That's because hormones your body makes to fight illness or stress can also cause blood sugar to rise. You may need to take extra diabetes medication to keep blood glucose in your target range during illness or stress.


Long-term complications

Keeping blood sugar in a healthy range can help prevent many diabetes-related complications. Long-term complications of hyperglycemia that isn't treated include:

  • Cardiovascular disease
  • Nerve damage (neuropathy)
  • Kidney damage (diabetic nephropathy) or kidney failure
  • Damage to the blood vessels of the retina (diabetic retinopathy) that could lead to blindness
  • Feet problems caused by damaged nerves or poor blood flow that can lead to serious skin infections, ulcerations and, in some severe cases, amputation
  • Bone and joint problems
  • Teeth and gum infections

Emergency complications

If blood sugar rises very high or if high blood sugar levels are not treated, it can lead to two serious conditions.

  • Diabetic ketoacidosis. This condition develops when you don't have enough insulin in your body. When this happens, glucose can't enter your cells for energy. Your blood sugar level rises, and your body begins to break down fat for energy.

    When fat is broken down for energy in the body, it produces toxic acids called ketones. Ketones accumulate in the blood and eventually spill into the urine. If it isn't treated, diabetic ketoacidosis can lead to a diabetic coma that can be life-threatening.

  • Hyperosmolar hyperglycemic state. This condition occurs when the body makes insulin, but the insulin doesn't work properly. Blood glucose levels may become very high — greater than 600 mg/dL (33.3 mmol/L) without ketoacidosis. If you develop this condition, your body can't use either glucose or fat for energy.

    Glucose then goes into the urine, causing increased urination. If it isn't treated, diabetic hyperosmolar hyperglycemic state can lead to life-threatening dehydration and coma. It's very important to get medical care for it right away.


To help keep your blood sugar within a healthy range:

  • Follow your diabetes meal plan. If you take insulin or oral diabetes medication, be consistent about the amount and timing of your meals and snacks. The food you eat must be in balance with the insulin working in your body.
  • Monitor your blood sugar. Depending on your treatment plan, you may check and record your blood sugar level several times a week or several times a day. Careful monitoring is the only way to make sure that your blood sugar level stays within your target range. Note when your glucose readings are above or below your target range.
  • Carefully follow your health care provider's directions for how to take your medication.
  • Adjust your medication if you change your physical activity. The adjustment depends on blood sugar test results and on the type and length of the activity. If you have questions about this, talk to your health care provider.

By Mayo Clinic Staff


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Hyperglycaemia (high blood sugar) - Illnesses & conditions

Hyperglycaemia is the medical term for a high blood sugar (glucose) level. It's a common problem for people with diabetes.

It can affect people with type 1 diabetes and type 2 diabetes, as well as pregnant women with gestational diabetes.

It can occasionally affect people who don't have diabetes, but usually only people who are seriously ill, such as those who have recently had a stroke or heart attack, or have a severe infection.

Hyperglycaemia shouldn't be confused with hypoglycaemia, which is when a person's blood sugar level drops too low.

This information focuses on hyperglycaemia in people with diabetes.

Is hyperglycaemia serious?

The aim of diabetes treatment is to keep blood sugar levels as near to normal as possible. But if you have diabetes, no matter how careful you are, you're likely to experience hyperglycaemia at some point.

It's important to be able to recognise and treat hyperglycaemia, as it can lead to serious health problems if left untreated.

Occasional mild episodes aren't usually a cause for concern and can be treated quite easily or may return to normal on their own. However, hyperglycaemia can be potentially dangerous if blood sugar levels become very high or stay high for long periods.

Very high blood sugar levels can cause life-threatening complications, such as:

  • diabetic ketoacidosis (DKA) – a condition caused by the body needing to break down fat as a source of energy, which can lead to a diabetic coma; this tends to affect people with type 1 diabetes
  • hyperosmolar hyperglycaemic state (HHS) – severe dehydration caused by the body trying to get rid of excess sugar; this tends to affect people with type 2 diabetes

Regularly having high blood sugar levels for long periods of time (over months or years) can result in permanent damage to parts of the body such as the eyes, nerves, kidneys and blood vessels.

If you experience hyperglycaemia regularly, speak to your doctor or diabetes care team. You may need to change your treatment or lifestyle to keep your blood sugar levels within a healthy range.

Symptoms of hyperglycaemia

Symptoms of hyperglycaemia in people with diabetes tend to develop slowly over a few days or weeks. In some cases, there may be no symptoms until the blood sugar level is very high.

Symptoms of hyperglycaemia include:

  • increased thirst and a dry mouth
  • needing to pee frequently
  • tiredness
  • blurred vision
  • unintentional weight loss
  • recurrent infections, such as thrush, bladder infections (cystitis) and skin infections

Symptoms of hyperglycaemia can also be due to undiagnosed diabetes, so see your GP if this applies to you. You can have a test to check for the condition.

What should my blood sugar level be?

When you're first diagnosed with diabetes, your diabetes care team will usually tell you what your blood sugar level is and what you should aim to get it down to.

You may be advised to use a testing device to monitor your blood sugar level regularly at home, or you may have an appointment with a nurse or doctor every few months to see what your level is.

Target blood sugar levels differ for everyone, but generally speaking:

  • if you monitor yourself at home – a normal target is 4-7mmol/l before eating and under 8. 5-9mmol/l two hours after a meal
  • if you're tested every few months – a normal target is below 48mmol/mol (or 6.5% on the older measurement scale)

What causes high blood sugar?

A variety of things can trigger an increase in blood sugar level in people with diabetes, including:

  • stress
  • an illness, such as a cold
  • eating too much, such as snacking between meals
  • a lack of exercise 
  • dehydration
  • missing a dose of your diabetes medication, or taking an incorrect dose
  • over-treating an episode of hypoglycaemia (low blood sugar)
  • taking certain medicines, such as steroid medication

Occasional episodes of hyperglycaemia can also occur in children and young adults during growth spurts.

Treating hyperglycaemia

If you've been diagnosed with diabetes and you have symptoms of hyperglycaemia, follow the advice your care team has given you to reduce your blood sugar level.

If you're not sure what to do, contact your GP or care team.

You may be advised to:

  • change your diet – for example, you may be advised to avoid foods that cause your blood sugar levels to rise, such as cakes or sugary drinks
  • drink plenty of sugar-free fluids – this can help if you're dehydrated
  • exercise more often – gentle, regular exercise such as walking can often lower your blood sugar level, particularly if it helps you lose weight
  • if you use insulin, adjust your dose – your care team can give you specific advice about how to do this

You may also be advised to monitor your blood sugar level more closely, or test your blood or urine for substances called ketones (associated with diabetic ketoacidosis).

Until your blood sugar level is back under control, watch out for additional symptoms that could be a sign of a more serious condition (see below).

When to get urgent medical attention

Contact your diabetes care team immediately if you have a high blood sugar level and experience the following symptoms:

  • feeling or being sick
  • abdominal (tummy) pain 
  • rapid, deep breathing
  • signs of dehydration, such as a headache, dry skin and a weak, rapid heartbeat
  • difficulty staying awake

These symptoms could be a sign of diabetic ketoacidosis or a hyperosmolar hyperglycaemic state (see above) and you may need to be looked after in hospital.

How to prevent hyperglycaemia

There are simple ways to reduce your risk of severe or prolonged hyperglycaemia:

  • Be careful what you eat – be particularly aware of how snacking and eating sugary foods or carbohydrates can affect your blood sugar level.
  • Stick to your treatment plan – remember to take your insulin or other diabetes medications as recommended by your care team.
  • Be as active as possible – getting regular exercise can help stop your blood sugar level rising, but you should check with your doctor first if you're taking diabetes medication, as some medicines can lead to hypoglycaemia if you exercise too much
  • Take extra care when you're ill – your care team can provide you with some "sick day rules" that outline what you can do to keep your blood sugar level under control during an illness.
  • Monitor your blood sugar level – your care team may suggest using a device to check your level at home, so you can spot an increase early and take steps to stop it.

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Diabetes is a disease in which the level of sugar (glucose) in the blood rises. Currently, there is a real epidemic of this disease in the world: every eleventh inhabitant of the planet suffers from diabetes, and according to experts, in 2030, every tenth person will be "diabetic".

High blood sugar is very dangerous. Like corrosion, it “corrodes” all organs. The eyes, kidneys, nerves, and heart suffer the most. Patients with diabetes die from heart attacks, strokes, lose their sight. They develop kidney failure and have to undergo hemodialysis several times a week (purification of the blood using an artificial kidney machine). Sometimes leg ulcers appear on the legs, leading to amputation.

Type 2 diabetes is the most common. It occurs due to excess weight, a sedentary lifestyle, the consumption of large amounts of high-calorie foods, burdened heredity. In this case, the body loses sensitivity to insulin, a hormone that is responsible for maintaining normal blood glucose levels.

Type 1 diabetes is less common. It develops due to the fact that there is a failure in the immune system, and the body begins to destroy its own cells that produce insulin. This process is triggered by some viruses (Coxsackie virus, mumps virus), toxic substances (nitroso compounds). In this disease, heredity also plays a role.

How can a person know if they have diabetes?

Unfortunately, our body does not provide a sensory organ that would capture high blood sugar. Therefore, at the beginning of the disease, when blood glucose is still not very high, the person does not feel anything unusual. But at the same time, the harmful effects of glucose on the body are already beginning. In the future, when blood sugar is already high enough, glucose begins to penetrate into the urine, attracting water to itself, and frequent urination appears, followed by thirst. Sometimes these symptoms prompt a person to see a doctor and get a diagnosis.

In some patients, the first symptom of diabetes may be itching (glucose accumulates in the skin and irritates the nerve endings) or pustular skin rashes, boils.

In type 2 diabetes, symptoms develop slowly and a person can walk for years with high blood glucose levels while the body is already suffering irreparable damage. In type 1 diabetes, the symptoms usually develop quite quickly, there is a strong thirst, frequent urination, weight loss, weakness. If help is not provided on time, then ketones accumulate in the body, nausea and vomiting, abdominal pain, shortness of breath appear, a person may fall into a coma.

What can I do to prevent diabetes?

To prevent the development of the disease, it is necessary, no matter how trite it may sound, to lead a healthy lifestyle. Engage in physical education, eat right (do not abuse fatty foods, sweets and pastries, alcohol), observe the regime of work and rest. Annually undergo medical examinations, donate blood for sugar.

With the appearance of thirst, frequent urination, skin itching, pustules or boils on the skin, sores on the feet, weight loss, weakness, it is necessary to check the level of blood glucose. The normal fasting blood glucose from a finger is from 3.3 to 5.5 mmol / l, from a vein up to 6.0 mmol / l. If these indicators are exceeded, it is necessary to consult an endocrinologist.

Should I panic if I am diagnosed with diabetes?

Diabetes mellitus is a serious disease that leads to adverse consequences. At the same time, today in the arsenal of an endocrinologist there are many effective drugs for lowering blood sugar levels and treating the consequences of diabetes. Therefore, if you follow the doctor's recommendations, you can effectively manage this disease and live a long and happy life.

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Increased glucose level. How to be and what to do?


In the body, all metabolic processes occur in close connection. When they are violated, a variety of diseases and pathological conditions develop, among which there is an increase in blood glucose.

Now people consume a very large amount of sugar, as well as easily digestible carbohydrates. There is even evidence that in the last century their consumption has increased 20 times. In addition, people's health has recently been negatively affected by ecology, the presence of a large amount of unnatural food in the diet.

Signs of an increase in blood sugar are very common in people, and the number of cases of diabetes in developed countries is now increasing every year.

Glucose is one of the main sources of energy and a universal fuel for cells, thanks to which our body performs a huge number of functions - for example, such as the work of the cardiovascular, nervous, and digestive systems.

The amount of glucose in the blood is called the sugar level and its rate depends on the work of the pancreas. This indicator can be influenced by factors such as: muscle activity, emotional state, diet.

A change in blood sugar levels is a signal of pathological processes in the body and may be a symptom of the development of serious diseases. Glycemia is the amount of glucose in a person's blood. To understand the essence of this concept, it is important to know what glucose is and what should be the indicators of glucose content.

The level of sugar in the blood, the norm of which is important for the normal functioning of the body, regulates insulin. But if enough of this hormone is not produced, or tissues respond inadequately to insulin, then blood sugar levels increase. The increase in this indicator is affected by smoking, unhealthy diet, stressful situations.

The answer to the question, what is the norm of sugar in the blood of an adult, is given by the World Health Organization. There are approved norms of glucose. So, if the indicators are below the norm, then the person has hypoglycemia, if higher - hyperglycemia. You need to understand that any option is dangerous for the body, as this means that violations occur in the body, and sometimes irreversible.

It is generally accepted that if capillary and venous blood is examined, then the result may fluctuate slightly. Therefore, when determining what the normal glucose content is, the result is slightly overestimated. The norm of venous blood is on average 3.5-6.1, capillary blood - 3.5-5.5. The norm of sugar after eating is up to 7.8 mmol / l. Above this indicator in healthy people, sugar does not rise.

But if the norm of glucose in the blood is slightly exceeded, and the indicators in the analysis from the finger are 5.6-6.1, and from the vein it is from 6.1 to 7, this condition is defined as prediabetes (impaired glucose tolerance).

With a result from a vein of more than 7 mmol / l (7.4, etc.), and from a finger - above 6.1, we are already talking about diabetes. For a reliable assessment of diabetes, a test is used - glycated hemoglobin.

Elevated blood sugar can be determined if a person has certain signs. The following symptoms, manifested in an adult and a child, should alert a person:

- weakness, severe fatigue; - increased appetite and at the same time weight loss; - thirst and a constant feeling of dryness in the mouth;

- profuse and very frequent urination, night trips to the toilet are typical; - pustules, boils and other lesions on the skin, such lesions do not heal well;

- regular manifestation of itching in the groin, in the genitals;

- deterioration of immunity, deterioration in performance, frequent colds, allergies in adults;

- deterioration of vision, especially in people who are already 50 years old.

The manifestation of such symptoms may indicate that there is an increased glucose in the blood. It is important to consider that signs of high blood sugar can be expressed only by some of the manifestations listed above. Therefore, even if only some symptoms of high sugar levels appear in an adult or a child, you need to take tests and determine glucose.

The risk group for diabetes includes those who have a hereditary predisposition to diabetes, obesity, pancreatic disease, etc.

In the presence of such signs, high blood sugar during pregnancy is also possible. In this case, it is very important to determine the exact causes of high sugar.

However, there is another test that is recommended for diagnosing diabetes in humans. It's called a glycated hemoglobin test, which is the amount of glucose in the blood that is bound to it. This study will show whether the patient with diabetes clearly controls blood glucose in the last 3 months.

Diabetes mellitus is a disease that can proceed without symptoms for a long time, and then turn into severe complications leading to disability and death. Diabetes mellitus occurs in 6% of the world's population, annually over 2 million people die from it. Moreover, in 90% of cases, patients are diagnosed with type 2 diabetes mellitus, in the development of which the most important role belongs to obesity and a sedentary lifestyle.

Proper nutrition plays an important role in the treatment of most diseases, but in diabetes it is of key importance. For example, in obese patients with type 2 diabetes, a diet that promotes weight loss can often stop the progression of the disease and the development of dangerous complications.

There are basic principles of nutrition for obesity and the risk of developing diabetes:

The diet should include the full range of macronutrients - proteins (15%), fats (25%) and carbohydrates (60%).

- When it comes to diabetes prevention, many people think about the need for almost complete restriction of carbohydrates in their diet. And at first glance, this looks quite logical - after all, it is carbohydrates that increase blood sugar levels. But still, you should not rush into this. Firstly, carbohydrates are different, and secondly, they perform many useful functions in our body. You just need to understand what carbohydrates and at what time you can afford. You can not exclude carbohydrates from the diet or limit their volume: this will not lead to a decrease in glucose levels - it will be synthesized in the body from fats and proteins. It is important to minimize the intake of carbohydrates that are easily digestible (sugar, sugary drinks, refined cereals) - they lead to a sharp jump in blood glucose, which is difficult to quickly compensate for the introduction of insulin or hypoglycemic drugs. It is necessary to give preference to "complex" carbohydrates, such as vegetables, fruits, whole grains - they are slowly digested and the level of glucose in the blood rises smoothly.

- it is necessary to reduce the content of animal fats in the diet, which contribute to the development of atherosclerosis, and give preference to vegetable fats, fatty fish varieties are also useful;

- you should eat often, fractionally and in small portions to avoid sharp "splashes" of blood glucose levels;

- the diet should be rich in vitamins and minerals: their deficiency exacerbates metabolic disorders.

In patients with normal weight, the daily calorie content of the diet should correspond to energy expenditure, and overweight patients (which is more common in type 2 diabetes) should consume fewer calories than they spend in order to gradually and smoothly get rid of extra pounds. This is the easiest and most effective way to reduce weight!

An important role belongs to physical activity. Muscle work contributes to the utilization of glucose, helps to reduce weight, increases the sensitivity of receptors to insulin. In addition, physical exercises create conditions for better blood supply to all organs, primarily the heart and the skeletal muscles themselves, the formation of new vessels to replace the destroyed ones, which avoids their “drying out”.

According to the Russian and foreign diabetic associations, very little is needed to prevent the development of diabetes - only 150 minutes of active physical activity per week. Of course, we are not talking about calm walking, but the type of activity does not matter.

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