Lightheadedness is a subtype of dizziness that is described as feeling as though you may faint. Dizziness and lightheadedness are common symptoms and usually do not indicate a serious underlying condition. Several conditions can cause lightheadedness, which occurs when the brain doesn't receive adequate amounts of blood and oxygen.
Dehydration
Dehydration occurs when the body does not have the amount of fluid that it is necessary to carry out normal and proper functions. Fluid loss and inadequate fluid intake contribute to the development of dehydration. Persistent vomiting and diarrhea are often common causes of dehydration as well. Symptoms of dehydration include dizziness and lightheadedness, dry mouth, decreased urine output, decreased tear production, sunken eyes and lethargy. Most cases of dehydration are treatable with increased fluid intake. In severe cases, or if dehydration affects an infant or elderly adult, hospitalization may be required. During hospitalization, intravenous fluids and electrolytes will be administered. According to the Medline Plus Medical Encyclopedia, severe dehydration is a life-threatening medical emergency.
Low Blood Pressure
The American Heart Association defines optimal blood pressure at around 120/80 mm Hg. The top or systolic number represents the pressure exerted when the heart contracts. The bottom or diastolic number represents the pressure when the heart relaxes. Normal blood pressure can vary based on the individual, which can make low blood pressure difficult to define. Generally, low blood pressure is defined as blood pressure that drops 20 mm Hg below an individual's normal blood pressure. Low blood pressure can be caused by certain medications, heart problems, allergic reactions, overexertion, nutritional deficiencies and blood loss. Other symptoms of low blood pressure include fainting, dehydration, lack of concentration, blurred vision, nausea, shallow breathing and fatigue. Low blood pressure that occurs independently does not usually require treatment. If low blood pressure is a symptom of another condition, treatment is aimed at correcting that condition.
Arrhythmia
An arrhythmia describes any change in the rhythm of the heartbeat. An arrhythmia can mean that the heart beats too quickly, too slowly or irregularly. Arrhythmias are a result of abnormal nerve impulses and electrical signals that control the beat of the heart. Alcohol abuse, smoking, stress and exercise can cause minor arrhythmias, while coronary artery disease, abnormal heart valve function and heart failure are common causes of more serious arrhythmias, according to the American Academy of Family Physicians. Additional symptoms of arrhythmias include tiredness, heart palpitations, fainting, shortness of breath and chest pain. Minor arrhythmias do not require any treatment, but arrhythmias that are caused by underlying heart conditions may require a pacemaker or surgery.
