Lightheadedness is a type of dizziness that occurs when a proper amount of blood is not being delivered to the brain. Red blood cells carry oxygen to the body tissues, so when blood does not reach the brain, the brain tissues also do not receive enough oxygen. The lack of oxygen causes lightheadedness, which is most often described as feeling like one may faint.
Low Blood Pressure
Low blood pressure, which is also called hypotension, occurs when the heart does not effectively pump blood throughout the entire area of the body. When blood pressure is low, sufficient oxygen cannot reach the brain. This can result in lightheadedness, blurred vision, nausea, an inability to concentrate, clammy skin, shallow breathing, fatigue and increased thirst. Although the definition of low blood pressure can vary between individuals, a blood pressure reading of less than 90/60 mm Hg is usually considered low, according to MayoClinic.com. Low blood pressure can occur as a result of pregnancy, blood loss, infections, allergic reactions, malnutrition, heart problems and thyroid diseases. In those with a clear cause of low blood pressure, treatment focuses on correcting the underlying problem. In cases where the cause cannot be determined, low blood pressure can be increased with increased salt intake, increased water intake and medications.
Dehydration
Dehydration occurs when the body loses more fluid than it takes in and no longer contains enough fluid to carry out its functions properly. The body is made up of approximately two-thirds water, according to KidsHealth, an information website sponsored by the Nemours Foundation. When this ratio is skewed, affected individuals may begin to feel lightheaded and thirsty. Urine production also decreases and the mouth becomes dry and sticky. Among the most common causes of dehydration are gastrointestinal illnesses that cause persistent and severe diarrhea and vomiting. Other causes include excessive sweating during physical activity and inadequate water intake. Mild cases of dehydration can be treated with the replacement of lost fluid. Some individuals who are severely dehydrated may require hospitalization, during which intravenous fluids and salts will be administered.
Hypoglycemia
Glucose, also referred to as blood sugar, is the main source of energy for the body. Hypoglycemia is a condition in which glucose in the blood is too low. MedlinePlus notes that low blood sugar is usually defined as anything below 70 mg/dL. Hypoglycemia can occur when the body's stores of glucose are depleted too quickly, glucose is released into the blood too slowly or too much insulin, which is a hormone that decreases blood sugar, is released by the pancreas. Symptoms of hypoglycemia include lightheadedness, vision problems, hunger, headache, irritability, nervousness, shaking, tingling and numbness of the skin, fatigue and weakness, according to MedlinePlus. Mild hypoglycemia can usually be treated with the consumption of carbohydrates, which provide glucose to the body. In severe cases, immediate glucose injections may be needed.
