Why Do I Get Nauseated & Lightheaded if I Don't Eat?

If you become nauseated or lightheaded when you don't eat, you may be experiencing hypoglycemia, a condition characterized by abnormally low blood sugar. In mild cases, hypoglycemia is relatively benign and easy to treat. In some cases, though, the symptoms can be severe or fail to resolve, which may warrant further investigation by your health care provider to determine if you have a more serious underlying condition.

Simply put, hypoglycemia refers to a blood glucose level that has dropped below normal. While most cells are capable of using a variety of stored nutrients for fuel, cells located in the brain require glucose almost exclusively. As a result, the body closely monitors blood glucose levels via a complex system of hormonally regulated checks and balances. Most people have heard of diabetes, a condition characterized by high blood sugar, or chronic hyperglycemia. Generally speaking, hypoglycemia is the opposite; though unlike diabetes, it is usually temporary.

Hypoglycemia occurs due to a number of factors. For some, low blood sugar is the result of waiting too long to eat. Because your brain cells need glucose, the lack of ingested calories accompanied by a falling glucose level triggers a chain of events. First, a hormone known as glucagon stimulates the release of sugar stored in the liver and muscle cells. If blood sugar continues to fall, your body activates the sympathetic nervous system. This adrenergic response is accountable for many of the classic symptoms associated with hypoglycemia.

Some people will never even realize that their blood sugar level has dropped because once detected, their bodies make the necessary adjustments. In those who do experience symptoms, the effects can vary from person to person but often include one or a combination of the following: nausea (including waking up nauseous), lightheadedness, palpitations, weakness, nervousness, sweating, intense hunger, headache and irritability. In severe and rare cases, hypoglycemia can cause serious problems and even death.

In the case of mild hypoglycemia, the treatment is often simple. Eat or drink something, particularly a food or beverage that is easily digested and high in simple sugars or carbohydrates. A glass of orange juice is a good example. But because other factors can cause and influence hypoglycemia, such as a medication you are taking or the presence of a disease or illness, individuals should consult a physician. This is especially true if symptoms are persistent, severe, frequent or do not respond to eating.