high sugar overview for patients

Overview

High blood sugar, also called hyperglycemia, happens when there is too much glucose (a type of sugar) in your blood. Glucose is your body's main fuel, but it needs a hormone called insulin to enter your cells. When the body does not make enough insulin, or does not use it properly, sugar stays in the blood instead of being used for energy.

Yes. Millions of people around the world live with high blood sugar. It is most often linked to diabetes, including type 1, type 2, and a condition called prediabetes where blood sugar is higher than normal but not yet diabetes.

High blood sugar can affect anyone at any age. It is more common in people who have diabetes, are overweight, are physically inactive, or have a family history of diabetes. It can also happen temporarily because of stress, illness, or certain medicines.

Symptoms

Common symptoms

• Feeling very thirsty
• Urinating more often than usual
• Feeling tired or weak
• Blurred vision
• Headaches
• Dry mouth or skin
• Unexpected weight loss

Symptoms in children

• Increased thirst and urination (including bedwetting)
• Low energy or irritability
• Stomach pain, nausea, or vomiting (in severe cases)
• Breathing fast or a fruity smell on the breath (emergency)

Symptoms in older adults

• Confusion or dizziness
• Extreme tiredness
• Dark, dry skin in patches
• Repeated infections such as bladder or skin infections
• Slow-healing cuts and sores

Causes

Main causes

• Diabetes (type 1, type 2, or other forms)
• Missing doses of diabetes medicines or insulin
• Eating large amounts of sugary or refined carbohydrate foods
• Physical illness or infection
• Severe stress or injury (such as surgery)
• Certain medicines, like steroid tablets taken for other conditions

Risk factors

• Overweight or obesity
• Low physical activity
• Family history of diabetes
• High blood pressure or abnormal cholesterol
• A history of gestational diabetes during pregnancy
• Smoking

When to see a doctor

See a doctor urgently if:

• Call your local emergency number or go to an emergency room if you have symptoms of very high blood sugar like confusion, vomiting, or fast breathing
• Call your local emergency number if your blood sugar is persistently very high and you feel unwell
• Call your local emergency number if you have signs of a serious infection such as a fever, shivering, or confusion

Book a routine appointment if:

• Make a routine appointment with your healthcare provider if you have ongoing thirst, frequent urination, tiredness, or blurry vision
• Make an appointment if you have risk factors for diabetes (such as overweight, inactivity, or a family history)
• Make an appointment if a prior test showed 'prediabetes' or borderline high blood sugar
• Talk to your doctor during pregnancy if you are worried about gestational diabetes

Diagnosis

Healthcare providers usually diagnose high blood sugar with a simple blood test. If you have not been tested, your doctor can order a test based on your symptoms and risk factors. For people who already have diabetes, routine blood sugar monitoring helps track whether their management plan is working.

Tests that may be done

• Fasting blood glucose test (taken after at least 8 to 12 hours without food)
• Haemoglobin A1C test (a blood test showing your average sugar level over 2–3 months)
• Oral glucose tolerance test (blood sugar measured after drinking a sugar solution)
• Random blood sugar test (taken at any time of day)

What to expect at your appointment

Tests are quick and usually involve a simple blood draw. You may be asked to fast beforehand for a fasting test. Your healthcare provider will explain what your results mean and what to do next.

Treatment

Treatment for high blood sugar focuses on bringing your glucose level back into a healthy range and keeping it there. The exact plan depends on whether you have diabetes, how high your sugar is, and your overall health. For most people, this involves a combination of lifestyle changes, regular monitoring, and medicines if needed.

Self-care at home

• Monitor your blood sugar as often as your care team recommends
• Take your medicines or insulin exactly as prescribed, even when you feel well
• Follow a balanced, portion-controlled diet with plenty of vegetables, whole grains, and lean protein
• Stay physically active on most days of the week
• Drink plenty of water and avoid sugary drinks
• Keep a diary of your readings to spot patterns and discuss them with your doctor

Medical treatments

There are several groups of medicines that lower blood sugar. Some help the body use insulin better, some help release more insulin, and others reduce the amount of sugar the liver produces. In type 1 diabetes, insulin is essential. For people with type 2 diabetes, oral medicines (taken by mouth) or injected non-insulin medicines may be used. Insulin is also an option when needed. Your doctor will choose a plan tailored to you and review it regularly. Never start, stop, or adjust a diabetes medicine without medical advice.

When is surgery considered?

In some situations, a type of weight-loss surgery (called bariatric surgery) may be considered for people with type 2 diabetes who are severely overweight. This decision is made by a specialist team. Surgery is not a routine treatment for high blood sugar itself.

Living with this condition

Living with high blood sugar is a daily balancing act. You will get used to checking your levels, making food choices, and taking medication on time. With the support of your healthcare team, these steps become a healthy routine. Remember that diabetes management is not about being perfect; it is about overall control over time.

Lifestyle tips

• Have a meal routine that fits your life and preferences
• Include regular physical activity like walking, swimming, or cycling
• Check your feet daily for cuts, blisters, or redness
• Bring your glucose monitor and diabetes supplies when travelling
• Wear medical identification if you take insulin or medicines that can cause low blood sugar

Diet and exercise

Eating well helps steady your blood sugar. Focus on vegetables, whole grains, beans, and lean proteins, and go easy on sugary drinks, white bread, rice, and pastries. Portion size matters. Physical activity helps your body use insulin better. Aim for at least 150 minutes of moderate activity a week, but even a 10-minute walk after meals is helpful. Talk to your team about a plan that is right for you.

Mental health and emotional wellbeing

Dealing with a high blood sugar diagnosis can be stressful. You might feel overwhelmed, frustrated, or anxious. This is completely normal. Diabetes distress—feeling weighed down by the daily demands of managing your condition—is common. Reach out to a psychologist or counsellor who understands diabetes, and remember that taking care of your mental health is part of taking care of your glucose.

Prevention

Type 1 diabetes cannot be prevented. But high blood sugar related to type 2 diabetes and prediabetes can often be prevented or delayed with a healthy weight, regular physical activity, and a balanced diet. Even small changes, like less sugar in drinks and more vegetables on your plate, can help.

Vaccines

People with diabetes are encouraged to protect themselves from infections such as flu, pneumonia, and COVID-19, and to stay up to date on vaccinations recommended by their healthcare provider. Vaccines do not prevent high blood sugar, but they help avoid illnesses that can make blood sugar levels rise.

Screening programmes

If you have risk factors—such as being over 40, being overweight, or having a parent or sibling with diabetes—speak to your GP about having your blood sugar checked. Pregnant women are usually screened for gestational diabetes. Repeat tests may be recommended every few years depending on your level of risk.

Complications

If left untreated

• Damage to small blood vessels in the eyes (retinopathy), which can affect vision
• Kidney disease (nephropathy), which can advance to kidney failure
• Nerve damage (neuropathy), causing pain, numbness, or tingling in hands and feet
• Higher risk of heart attack, stroke, and foot ulcers
• Diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS) — serious, life-threatening emergencies

Long-term outlook

With early treatment and steady glucose control, most people with high blood sugar can prevent or delay complications significantly. Living well with diabetes is entirely possible. Many people successfully manage their blood sugar and enjoy full, active lives. Your healthcare team is there to help you every step of the way.

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