What is a dangerous number for blood sugar

Blood glucose that gets too high or too low can be dangerous. To stay safe and healthy, check your blood glucose regularly and watch for certain symptoms, like being very hungry, tired or sleepy. If your blood glucose is outside the normal range, take the steps described below to start feeling better.

Table of Contents Show

High Blood Glucose: Hyperglycemia
High Blood Glucose: Diabetic Ketoacidosis (DKA)
Low Blood Glucose: Hypoglycemia
Topic Overview
Mild high blood sugar
Moderate to severe high blood sugar
At what blood sugar level is it dangerous?
What blood sugar level is too high?

High Blood Glucose: Hyperglycemia

Hyperglycemia means that you have too much blood glucose. It happens when your blood glucose level is around 200 mg/dL or higher. Hyperglycemia can happen if you miss taking your diabetes medications, eat too much or do not get enough exercise. Sometimes, the medications you take for other problems cause high blood glucose.

Symptoms of hyperglycemia include:

Being very thirsty
Being very tired
Having blurry vision
Having to urinate often

If you have these symptoms, check your blood glucose right away. If it’s too high, follow these steps:

Check your blood glucose every four hours. If your level does not go down after two checks or your symptoms get worse, call a member of your diabetes team.
Drink water or other sugar-free liquids, such as diet soda or Crystal Light.
You may need to take an extra dose of insulin. Your diabetes educator talks with you more about this.

High Blood Glucose: Diabetic Ketoacidosis (DKA)

If your insulin level is too low, your blood glucose could become so high that it is unsafe. You might develop a serious problem called diabetic ketoacidosis (or DKA). This usually happens in people with Type 1 diabetes and those with glucose levels over 500.

If you have DKA, chemicals called ketones start to make a lot of acid in your body. The acid and high blood glucose can make you very sick. You might also become dehydrated (lose body fluid). You can prevent DKA by carefully giving yourself the correct insulin dose every day.

If you have any of the following symptoms of DKA, get to your local emergency department right away. You need to be treated with insulin and fluids that are given to you through an IV (a thin tube placed in your arm):

Blurry vision
Decreased appetite
Dry mouth, eyes or skin
Fast breathing
Feeling confused or irritable
Feeling very weak or tired
Fruity-smelling breath
Stomach pain, nausea or vomiting

Low Blood Glucose: Hypoglycemia

Hypoglycemia can occur when blood glucose drops below normal levels or drops too quickly. Your blood glucose level is too low if it is under 70 mg/dL.

Hypoglycemia can be caused by:

A combination of these factors
Being more active than usual
Drinking alcohol
Eating at the wrong time for the medications you take
Skipping or not finishing meals or snacks
Taking too much diabetes medication

You can have hypoglycemia without any symptoms. That makes it important to check your blood glucose levels regularly. When hypoglycemia does cause symptoms, they can include:

Being sweaty
Fast heartbeat
Feeling irritable
Feeling shaky
Feeling tired
Headache
Hunger

If you have these symptoms, check your blood glucose right away. If it is too low (under 70 mg/dL), take something with sugar right away. This quickly raises your blood glucose level. Some good options include:

Five to six hard candies
One-half cup (4 oz) of fruit juice or regular soda
Three glucose tablets

You should also check your blood glucose again after 15 minutes. If it’s still low, again take something with sugar. Check your blood glucose level again after another 15 minutes. If it is still low, call a member of your diabetes team. If your next meal is more than an hour away, eat a small snack.

*The content on this website is for informational purposes only and is not medical advice. Please consult a physician regarding your specific medical condition, diagnosis and/or treatment.

Topic Overview

High blood sugar (hyperglycemia) is most often seen in people who have diabetes that isn't well controlled. The symptoms of high blood sugar can be mild, moderate, or severe.

Mild high blood sugar

If your blood sugar levels are consistently higher than your target range (usually 11 mmol/L to 20 mmol/L, and 11 mmol/L to 14 mmol/L in children), you may have mild symptoms of high blood sugar. You may urinate more than usual if you are drinking plenty of liquids. Some people who have diabetes may not notice any symptoms when their blood sugar level is in this range. The main symptoms of high blood sugar are:

Increased thirst.
Increased urination.
Weight loss.
Fatigue.
Increased appetite.

Young children are unable to recognize symptoms of high blood sugar. Parents need to do a home blood sugar test on their child whenever they suspect high blood sugar.

If you don't drink enough liquids to replace the fluids lost from high blood sugar levels, you can become dehydrated. Young children can become dehydrated very quickly. Symptoms of dehydration include:

A dry mouth and increased thirst.
Warm, dry skin.

Moderate to severe high blood sugar

If your blood sugar levels are consistently high (usually above 20 mmol/L in adults and above 14 mmol/L in children), you may have moderate to severe symptoms of high blood sugar. These symptoms include:

Blurred vision.
Extreme thirst.
Light-headedness.
Flushed, hot, dry skin.
Restlessness, drowsiness, or difficulty waking up.

If your body produces little or no insulin (people with type 1 diabetes and some people with type 2 diabetes), you also may have:

Rapid, deep breathing.
A fast heart rate and a weak pulse.
A strong, fruity breath odour.
Loss of appetite, belly pain, and/or vomiting.

If your blood sugar levels continue to rise, you may become confused and lethargic. You also may become unconscious if your blood sugar levels are very high.

Credits

Current as of: July 28, 2021

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Donald Sproule MDCM, CCFP - Family Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Rhonda O'Brien MS, RD, CDE - Certified Diabetes Educator

At what blood sugar level is it dangerous?

A level of blood sugar above 250 mg/dL or under 50 mg/dL is dangerous and requires medical emergency treatment. The optimal blood sugar level that you want to achieve is generally between 70 and 130 mg/dL.

What blood sugar level is too high?

High Blood Glucose: Hyperglycemia Hyperglycemia means that you have too much blood glucose. It happens when your blood glucose level is around 200 mg/dL or higher. Hyperglycemia can happen if you miss taking your diabetes medications, eat too much or do not get enough exercise.