Hyperglycaemia (High Blood Sugar)
Informed by recognized medical guidance
If symptoms are severe, worsening, or life-threatening, seek urgent medical care now.
Overview
Hyperglycaemia, also known as high blood sugar, happens when there is too much sugar (glucose) in your bloodstream. It is a common issue for people with diabetes, but can also occur temporarily in others. Your body uses sugar for energy, but when levels get too high, it can cause problems.
Key facts
- High blood sugar often means your body isn't making enough insulin or can't use insulin properly.
- Untreated hyperglycaemia can lead to serious complications, but it is manageable with proper care.
- It can be a temporary condition, like after a large meal, or a sign of diabetes needing ongoing management.
Yes, hyperglycaemia is very common, especially among people with diabetes. Millions of people worldwide experience it regularly.
It affects people with type 1 or type 2 diabetes most often. It can also occur in people without diabetes during illness, stress, or after eating very sugary foods.
Symptoms
- If you have trouble breathing or feel very confused
- If you become unconscious or extremely drowsy
- If you have fruity-smelling breath (a sign of diabetic ketoacidosis)
- ⚠If you have a fever with high blood sugar
- ⚠If you are vomiting and can't keep down fluids or food
- ⚠If you have severe abdominal pain
Common symptoms
- Feeling very thirsty
- Urinating more often than usual, especially at night
- Blurred vision
- Feeling tired or weak
- Headaches
Symptoms in children
- Increased thirst and frequent urination (bedwetting in toilet-trained children)
- Unexplained weight loss
- Feeling very hungry or irritable
Symptoms in older adults
- Dry mouth and feeling excessively thirsty
- More frequent infections, like urinary tract infections
- Confusion or dizziness
- Slow-healing cuts or bruises
Causes
Main causes
- Not having enough insulin in your body (common in type 1 diabetes)
- Your body not responding well to insulin (insulin resistance, common in type 2 diabetes)
- Eating too much carbohydrate or sugary food without enough insulin or diabetes medication
- Being sick or having an infection
- Stress, lack of exercise, or skipping diabetes medication
Risk factors
- Having type 1 or type 2 diabetes
- Being overweight or obese
- Leading a sedentary lifestyle
- Eating a diet high in sugar and refined carbohydrates
- Having a family history of diabetes
When to see a doctor
See a doctor urgently if:
- If your blood sugar readings are consistently above 13.9 mmol/L (250 mg/dL)
- If you have symptoms of diabetic ketoacidosis (nausea, vomiting, abdominal pain, confusion)
- If you have a high fever or feel extremely ill
Book a routine appointment if:
- If you have been diagnosed with diabetes and your blood sugar is often higher than your target
- If you have new or worsening symptoms of thirst, urination, or blurred vision
- If you need help adjusting your diabetes management plan
Diagnosis
A doctor diagnoses hyperglycaemia with a simple blood test to measure your blood sugar level. They may also use a urine test to check for ketones.
Tests that may be done
- Fasting blood sugar test (taken after not eating for at least 8 hours)
- Random blood sugar test (taken at any time)
- HbA1c test (shows your average blood sugar over the past 2-3 months)
- Urine ketone test (to detect ketones, a sign of severe high blood sugar)
What to expect at your appointment
Your doctor will explain what your results mean. They may diagnose diabetes or pre-diabetes, or confirm you have hyperglycaemia. They will work with you to create a plan to manage it.
Treatment
Treatment for hyperglycaemia focuses on bringing your blood sugar back down to a healthy level. This often involves changing what you eat, increasing physical activity, and taking medication or insulin as prescribed. The goal is to prevent long-term damage and keep you feeling well.
Self-care at home
- Drink plenty of water to help flush out excess sugar through your urine
- Get regular physical activity – walking, swimming, or cycling helps your body use glucose
- Follow a healthy diet – choose whole grains, vegetables, and lean proteins; limit sugary drinks and sweets
- Monitor your blood sugar levels as recommended by your care team
Medical treatments
For people with diabetes, treatment includes medications that help lower blood sugar, often taken as pills or injections. Some people need insulin therapy. Your healthcare provider will prescribe the right treatment for you. Never adjust your medication without talking to your doctor.
When is surgery considered?
Surgery is not usually used to treat hyperglycaemia itself. However, bariatric surgery may be considered for some people with type 2 diabetes and severe obesity as a way to improve blood sugar control.
Living with this condition
Living with hyperglycaemia means being aware of your blood sugar levels and making daily choices to keep them in range. It can feel like a lot of work at first, but many people manage it successfully with support from their healthcare team.
Lifestyle tips
- Check your blood sugar regularly as advised
- Keep a log of your readings to share with your doctor
- Carry a snack or glucose tablets in case your blood sugar drops too low
- Wear a medical ID bracelet if you have diabetes
Diet and exercise
Eating a balanced diet with vegetables, fruits, whole grains, and lean proteins can help. Regular exercise – at least 150 minutes per week of moderate activity like brisk walking – improves how your body uses insulin. Always talk to your doctor before starting a new exercise plan.
Mental health and emotional wellbeing
Managing a condition like hyperglycaemia can be stressful. You might feel anxious about blood sugar checks, frustrated by food restrictions, or discouraged by setbacks. These feelings are normal. Reaching out to a counsellor or support group can help.
Prevention
For people with diabetes, you can often prevent hyperglycaemia by following your treatment plan, eating healthy foods, staying active, and monitoring your levels. For those at risk of type 2 diabetes, lifestyle changes like weight loss and exercise can sometimes prevent or delay high blood sugar.
Vaccines
If you have diabetes, getting recommended vaccines – like the flu shot and pneumonia vaccine – can help prevent infections that might raise your blood sugar.
Screening programmes
If you are at risk of diabetes (for example, if you are overweight or have a family history), your doctor may recommend regular blood sugar checks. Early detection makes management easier.
Complications
If left untreated
- Long-term damage to blood vessels, increasing risk of heart disease and stroke
- Kidney disease (nephropathy)
- Nerve damage (neuropathy), causing pain or numbness in your feet and hands
- Eye damage (retinopathy) which can lead to blindness
- Diabetic ketoacidosis (DKA), a life-threatening emergency
Long-term outlook
With the right care, many people with hyperglycaemia live full, active lives. Keeping blood sugar in a healthy range can prevent or delay complications. Your healthcare team is there to help you every step of the way.
Find support
International organisations
Local organisations
- Diabetes UK ↗ · United Kingdom
- American Diabetes Association ↗ · United States
Helplines
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.