Increased Blood Sugar

Overview

Increased blood sugar, known medically as hyperglycemia, means there is more glucose circulating in the blood than there should be. Glucose is the body's main fuel, and its level is normally kept in a narrow range by insulin, a hormone made by the pancreas. When the body does not make enough insulin or cannot use it well, glucose builds up in the blood.

A single high reading after a sugary meal is not necessarily a problem, but consistently elevated blood sugar is the central feature of prediabetes and diabetes. Mildly raised levels often cause no symptoms and are found on a routine blood test. Higher levels can cause noticeable symptoms, and very high blood sugar can become a dangerous emergency. Because increased blood sugar is both common and treatable, it is important to recognize and act on it.

Common Causes

Blood sugar can rise for several reasons:

• Diabetes: The most common cause of persistently high blood sugar, where the body lacks insulin or cannot use it effectively.
• Prediabetes: Blood sugar higher than normal but not yet in the diabetes range.
• Diet: Large amounts of sugary or carbohydrate-rich food temporarily raise blood sugar.
• Illness and infection: Stress on the body, including infections, can push blood sugar up.
• Medications: Steroids and some other drugs can raise blood sugar.
• Stress: Physical or emotional stress releases hormones that increase glucose.
• Inactivity and weight gain: Which reduce the body's sensitivity to insulin.
• Hormonal conditions: Such as Cushing syndrome.

Associated Symptoms

Mildly increased blood sugar often causes no symptoms. As levels rise, common symptoms include:

• Increased thirst and a dry mouth
• Frequent urination, including at night
• Fatigue and low energy
• Blurred vision
• Unexplained weight loss
• Slow-healing cuts and frequent infections
• Increased hunger

Very high blood sugar can cause nausea, vomiting, deep or rapid breathing, fruity-smelling breath, drowsiness, and confusion. These are warning signs of a dangerous complication and need emergency care.

Diagnosis & Evaluation

Blood sugar is measured and evaluated with several tests:

• Fasting blood glucose: Measured after not eating overnight.
• HbA1c: A blood test reflecting average blood sugar over the past two to three months.
• Random or post-meal glucose: A reading taken at any time or after eating.
• Oral glucose tolerance test: Measuring how the body handles a glucose drink.

These tests determine whether blood sugar is normal, in the prediabetes range, or in the diabetes range, guiding next steps.

Treatment & Management

Managing increased blood sugar focuses on bringing it into a healthy range and treating any underlying diabetes:

• Healthy eating: Balanced meals, controlling portions of sugary and refined-carbohydrate foods, and plenty of vegetables and fiber.
• Physical activity: Regular exercise improves how the body uses insulin.
• Weight management: Even modest weight loss can lower blood sugar.
• Medications: Such as metformin or other diabetes medicines, and insulin when needed.
• Monitoring: Checking blood sugar as advised and attending follow-ups.
• Treating contributing factors: Such as infections or reviewing medications that raise sugar.

For prediabetes, lifestyle changes can often prevent or delay diabetes. A doctor tailors the plan to your situation.

Self-Care & Prevention

Increased blood sugar can often be prevented or improved through everyday habits, which are also the foundation of managing prediabetes and diabetes:

• Eating balanced meals with controlled portions of sugary and refined-carbohydrate foods, and plenty of vegetables, fiber, and whole grains
• Being physically active most days, since muscles use glucose during activity
• Maintaining a healthy weight, as even modest weight loss improves blood sugar
• Limiting sugary drinks and choosing water instead
• Managing stress and getting enough sleep, both of which affect blood sugar
• Attending recommended screenings, especially if you have risk factors

For people with prediabetes, these changes can prevent or delay the onset of diabetes. If you already have diabetes, following your treatment and monitoring plan keeps blood sugar in a safer range and lowers the risk of complications over time.

When to See a Doctor

See a doctor if a blood test shows increased blood sugar, or if you have symptoms such as increased thirst, frequent urination, fatigue, blurred vision, or unexplained weight loss, so you can be tested for prediabetes or diabetes.

Seek emergency care if blood sugar is very high and accompanied by nausea, vomiting, abdominal pain, deep or rapid breathing, fruity-smelling breath, drowsiness, or confusion. These can signal a life-threatening complication of very high blood sugar that needs immediate treatment.

Related Topics

Frequently Asked Questions

References

1. Centers for Disease Control and Prevention (CDC). Diabetes Basics.
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetes Tests & Diagnosis.
3. Mayo Clinic. Hyperglycemia in diabetes - Symptoms and causes.
4. MedlinePlus, U.S. National Library of Medicine. High blood sugar.