What Level of Blood Sugar is Dangerous?: You Need to Know

Learn about dangerous blood sugar levels, their symptoms, causes, and management. Protect your health by understanding when blood sugar levels become dangerous.

Maintaining healthy blood sugar levels is critical for overall well-being, especially for individuals with diabetes. Understanding what constitutes a dangerous blood sugar level can help you take proactive measures to prevent serious health complications.

This comprehensive guide will delve into the nuances of blood sugar levels, what makes them dangerous, and how to manage them effectively.

What is Blood Sugar?

Blood sugar, or blood glucose, is the primary type of sugar found in your blood. It comes from the food you eat and serves as the main energy source for your body’s cells. The levels of glucose in your blood are regulated by insulin, a hormone produced by the pancreas.

For those with diabetes, the body either doesn’t produce enough insulin or can’t use it effectively, leading to abnormal blood sugar levels.

Understanding Blood Sugar Levels

Blood sugar levels can vary throughout the day based on factors such as food intake, physical activity, and medication. Here’s a general overview of blood sugar level ranges:

  • Normal blood sugar levels: Fasting blood sugar levels of 70-99 mg/dL (3.9-5.5 mmol/L) and less than 140 mg/dL (7.8 mmol/L) two hours after eating.
  • Prediabetes: Fasting blood sugar levels of 100-125 mg/dL (5.6-6.9 mmol/L) and 140-199 mg/dL (7.8-11.0 mmol/L) two hours after eating.
  • Diabetes: Fasting blood sugar levels of 126 mg/dL (7.0 mmol/L) or higher on two separate tests, or a two-hour blood sugar level of 200 mg/dL (11.1 mmol/L) or higher during an oral glucose tolerance test.

What is a Dangerous Blood Sugar Level?

A dangerous blood sugar level refers to any extreme deviation from the normal range that can lead to severe health complications. Both hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar) can be dangerous if not managed properly.

Hyperglycemia: High Blood Sugar Levels

Hyperglycemia occurs when blood sugar levels are too high. It is particularly dangerous for individuals with diabetes as it can lead to both short-term and long-term complications.

Symptoms of Hyperglycemia

  • Increased thirst
  • Frequent urination
  • Fatigue
  • Blurred vision
  • Headache
  • Nausea and vomiting
  • Shortness of breath
  • Dry mouth

Dangerous Hyperglycemia Levels

Blood sugar levels consistently above 180 mg/dL (10.0 mmol/L) are considered high. Levels above 240 mg/dL (13.3 mmol/L) require immediate medical attention, and levels above 600 mg/dL (33.3 mmol/L) can lead to diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS), both of which are life-threatening conditions.

Hypoglycemia: Low Blood Sugar Levels

Hypoglycemia occurs when blood sugar levels drop too low. It is a dangerous blood sugar level scenario that requires prompt attention to prevent severe outcomes.

Symptoms of Hypoglycemia

  • Shakiness
  • Sweating
  • Rapid heartbeat
  • Hunger
  • Irritability or confusion
  • Dizziness
  • Blurred vision
  • Weakness or fatigue
  • Seizures (in severe cases)
  • Loss of consciousness

Dangerous Hypoglycemia Levels

Blood sugar levels below 70 mg/dL (3.9 mmol/L) are considered low and require immediate action. Levels below 54 mg/dL (3.0 mmol/L) are dangerously low and need urgent treatment to prevent severe hypoglycemia and its potential complications, such as seizures, loss of consciousness, or even death.

Causes of Dangerous Blood Sugar Levels

Understanding the causes of dangerous blood sugar levels can help you take preventative measures. Here are some common factors that can lead to hyperglycemia and hypoglycemia:

Causes of Hyperglycemia

  1. Excessive carbohydrate intake: Consuming too many carbs without enough insulin to process them can spike blood sugar levels.
  2. Insufficient insulin or medication: Missing doses or not taking enough insulin or diabetes medication can lead to high blood sugar.
  3. Infections or illness: These can cause stress on the body, leading to higher blood sugar levels.
  4. Stress: Physical or emotional stress can increase blood sugar levels due to the release of stress hormones like cortisol.
  5. Sedentary lifestyle: Lack of physical activity can lead to weight gain and insulin resistance, increasing blood sugar levels.
Blood Sugar Level

Causes of Hypoglycemia

  1. Too much insulin or medication: Taking more insulin or diabetes medication than needed can lower blood sugar levels too much.
  2. Skipping meals or not eating enough: Missing meals or not eating enough carbohydrates can cause low blood sugar.
  3. Excessive physical activity: Exercising more than usual without adjusting food intake or medication can lead to hypoglycemia.
  4. Alcohol consumption: Drinking alcohol, especially on an empty stomach, can cause blood sugar levels to drop.

Managing Dangerous Blood Sugar Levels

Effectively managing dangerous blood sugar levels involves a combination of lifestyle changes, medication, and regular monitoring. Here’s how you can manage both hyperglycemia and hypoglycemia:

Managing Hyperglycemia

  1. Monitor blood sugar levels regularly: Keep track of your blood sugar levels to identify any spikes and take action promptly.
  2. Adjust your diet: Focus on a balanced diet that includes whole grains, lean proteins, healthy fats, and plenty of vegetables. Avoid sugary foods and beverages.
  3. Stay hydrated: Drinking plenty of water helps flush excess sugar from your bloodstream through urine.
  4. Exercise regularly: Physical activity helps lower blood sugar levels by increasing insulin sensitivity.
  5. Take medication as prescribed: Follow your healthcare provider’s recommendations regarding insulin or oral diabetes medications.

Managing Hypoglycemia

  1. Monitor blood sugar levels frequently: Check your levels before and after meals, and before and after exercise.
  2. Carry fast-acting carbohydrates: Always have glucose tablets, fruit juice, or candy on hand to quickly raise your blood sugar levels if they drop too low.
  3. Eat regular meals and snacks: Avoid skipping meals and ensure you consume enough carbohydrates.
  4. Adjust insulin or medication doses: Work with your healthcare provider to adjust your medication as needed based on your activity level and food intake.
  5. Avoid alcohol on an empty stomach: If you drink alcohol, consume it with a meal or snack to prevent hypoglycemia.

When to Seek Medical Help

Knowing when to seek medical help is crucial for managing dangerous blood sugar levels effectively. Here are some signs that indicate you need to consult a healthcare professional:

For Hyperglycemia

  • Blood sugar levels consistently above 240 mg/dL (13.3 mmol/L)
  • Symptoms of diabetic ketoacidosis (DKA) such as fruity-smelling breath, rapid breathing, and confusion
  • Persistent high blood sugar despite following your treatment plan

For Hypoglycemia

  • Blood sugar levels below 54 mg/dL (3.0 mmol/L) that do not improve with treatment
  • Severe symptoms such as seizures, loss of consciousness, or inability to eat or drink
  • Frequent episodes of low blood sugar


Understanding and managing dangerous blood sugar levels is essential for maintaining your health and preventing serious complications.

By being vigilant about monitoring your blood sugar, making necessary lifestyle adjustments, and seeking professional guidance, you can effectively manage both hyperglycemia and hypoglycemia. Remember, maintaining a balance is key to living a healthy life with diabetes.

This comprehensive guide should provide you with a clear understanding of what dangerous blood sugar levels are, how to recognise them, and how to manage them effectively. Stay proactive and informed to ensure your well-being and quality of life.

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Peter K. Attia

Passionate about empowering individuals through dietary supplements, I specialize in researching and recommending the best products for optimal health. With a focus on health supplements, my mission is to provide insightful, scientifically backed advice to help individuals achieve their wellness goals.

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