Low blood glucose, also called low blood sugar or hypoglycemia, occurs when the level of glucose in your blood drops below what is healthy for you.
For many people with diabetes, this means a blood glucose reading lower than 70 milligrams per deciliter (mg/dL).
Your number might be different, so check with your doctor or health care team to find out what blood glucose level is low for you.
How common is low blood glucose?
Low blood glucose is common among people with type 1 diabetes and among people with type 2 diabetes who take insulin or some other diabetes medicines.
In a large global study of people with diabetes who take insulin, 4 in 5 people with type 1 diabetes and nearly half of those with type 2 diabetes reported a low blood sugar event at least once over a 4-week period.
Severely low blood glucose, defined as when your blood glucose level drops so low you can’t treat it yourself, is less common.
Among U.S. adults with diabetes who take insulin or some diabetes medicines that help the pancreas release insulin into the blood, 2 in 100 may develop severely low blood glucose each year.
Who is more likely to develop low blood glucose?
You are more likely to develop low blood glucose if you
have type 1 diabetes
take insulin or some other diabetes medicines
are age 65 or older5
had low blood glucose before
have other health problems, such as kidney disease, heart disease, or cognitive impairment NIH external link
Low blood glucose during sleep
Your blood glucose level can drop while you sleep and stay low for several hours, causing serious problems.
Symptoms of low blood glucose while you sleep can include
crying out or having nightmares
sweating enough to make your pajamas or sheets damp
feeling tired, irritable, or confused after waking up
Although you may not wake up or notice any symptoms, low blood glucose can interfere with your sleep, which may affect your quality of life, mood, and ability to work.
Having low blood glucose during sleep can also make you less likely to notice and respond to symptoms of low blood glucose during the day.
What are the complications of low blood glucose?
Mild-to-moderate low blood glucose can be easily treated. But severely low blood glucose can cause serious complications, including passing out, coma, or death.
Repeated episodes of low blood glucose can lead to
high blood glucose levels, if worry or fear of low blood glucose keeps you from taking the medicines you need to manage your diabetes;
hypoglycemia unawareness, a condition in which you don’t notice any symptoms of low blood glucose until your blood glucose level has dropped very low.
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