What is low blood sugar?

Low blood sugar is called hypoglycemia (hypo is from the Greek for "low"). Occasionally, your blood sugar level may drop to a level where you don't have enough sugar in your blood to adequately fuel the body's normal functions. Organs in the body that use a high amount of glucose include your brain, heart, kidneys, and muscles.

What causes low blood sugar?

Hypoglycemia can be a side effect of some medications for type 1 and 2 diabetes. Dosage adjustments or taking medications without food can trigger low blood sugars. Exercising more than usual and eating less than you normally do can also cause hypoglycemia.

The best way to avoid hypoglycemia is to monitor blood glucose levels at home and take your medications as directed by your physician, primary health care provider, and pharmacist. If you are managing your diabetes only with changes to your diet and exercise level, it is highly unlikely that you would have low blood sugars.

How will I know if my sugar is low?

Symptoms of hypoglycemia include:

  • anxiety
  • changes to vision
  • confusion
  • difficulty concentrating
  • difficulty speaking
  • dizziness
  • fatigue
  • headache
  • hunger
  • irritability
  • nausea
  • numbness or tingling in tongue or lips
  • pale skin
  • palpitations (fast heart rate)
  • sweating
  • tremor or shakiness
  • weakness

If your blood glucose level is extremely low, it is possible to have a seizure or lose consciousness, but these situations are rare.

What should I do if I'm feeling that I might have low blood sugar?

A health care professional can teach you how to recognize the warning signs of hypoglycemia. People with diabetes should carry candy, sugar, or glucose tablets to treat hypoglycemia. Make sure that you tell others – your friends, family, and coworkers – about the signs of low blood sugar and what to do about it if it happens.

Hypoglycemia may be affected by your age, any medical conditions you may have, medications you’re taking, what you eat, and how much (and what kind of) exercise you get. Your treatment will depend on how severe the hypoglycemia is. Talk to your diabetes educator or health care provider to develop an individualized hypoglycemia plan to manage low blood sugar levels.