Hypoglycemia Overview

What happens when your blood glucose level drops too low

Hypoglycemia means low (hypo) glucose (gly) in the blood (emia). Your body needs glucose to properly function. Your cells rely on glucose for energy.

Glucose comes from the foods you eat. Carbohydrates (e.g., fruit, bread, potatoes, milk, and rice) are the biggest source of glucose in a typical diet, and your body breaks down carbohydrates into glucose. The glucose is then transported in your blood to cells that need it; it gives your body energy.

However, in order to use the glucose, your body needs insulin. This is a hormone produced by the pancreas. Insulin helps transport glucose into the cells, particularly the muscle cells.

Sometimes, your blood glucose level can drop too low—that's hypoglycemia. It usually happens quite quickly, and it can be handled quite quickly, as well.

People with type 1 diabetes do not make insulin to help their bodies use glucose, so they have to take insulin, which is injected under the skin. People with type 2 diabetes fall into two categories when it comes to insulin: either their body doesn't make enough, or their body is unable to use it well (insulin resistance).

Normal Blood Glucose
The American Diabetes Association published the Standards of Medical Care in Diabetes that provide recommended target blood glucose ranges for people with and without diabetes.

The standard for measuring blood glucose is “mg/dL,” which means milligrams per deciliter.

            People without Diabetes
            Fasting glucose (at least 8 hours without eating)          70 to 99 mg/dL
            After eating (called postprandial)                                       70 to 140 mg/dL
 
            Goals for People with Diabetes
            Before eating                                                                         70 to 130 mg/dL
            1 to 2 hours after starting a meal                                       below 180 mg/dL
 

 

View Sources

Sources

  • American Diabetes Association.  Standards of Medical Care in Diabetes—2009. Diabetes Care. 2009;32:S13-61.
  • National Diabetes Information Clearinghouse (NDIC) Web site.  Hypoglycemia page.  Available at:  http://diabetes.niddk.nih.gov/dm/pubs/hypoglycemia/.  Accessed May 5, 2009.