Dizziness, the feeling of unsteadiness or the sensation of movement or spinning, can occur due to various conditions. Illnesses that upset the equilibrium mechanism in the inner ear, such as the common cold, flu or allergies, can result in dizziness. Suddenly changing positions or changes in the level of sugar in the blood can also cause dizziness. Although most causes of dizziness are not serious, according to MedLinePlus and the National Institutes of Health, heart issues that affect the flow of blood to the brain can also cause dizziness.
Hypertension
Hypertension, or high blood pressure, affects one in three adults in the United States, according to the National heart Lung and Blood Institute. Blood pressure is the force of blood against the walls of arteries and is recorded as two numbers—the systolic pressure, or the pressure the heart exerts when it pumps, and the diastolic pressure he force the blood vessels exert as they resist the flow of blood. Doctors consider a systolic reading over 140 mm Hg and a diastolic reading over 90 mm Hg as high blood pressure, according to the American Heart Association.
Continuous high blood pressure damages the walls of the blood vessels. This damage causes the blood vessels to become thick, hard and stiff, a condition known as arteriosclerosis. Arteriosclerosis in the blood vessels leading to the brain restricts the flow of blood to the brain, resulting in dizziness.
Hypotension
Hypotension describes a condition of abnormally low blood pressure. This condition commonly causes dizziness and fainting due to a lack of blood flow to the brain. Doctors generally consider blood pressure low, as defined by MayoClinic.com, when the systolic pressure reads 90 mm Hg or less and the diastolic pressure reads 60 mm Hg or less.
Several heart conditions can cause hypotension. When the heart fails to receive enough blood, the cells in the heart muscle become damaged, a condition known as a heart attack. Heart failure describes a condition that occurs when the heart fails to pump enough blood to meet the needs of the body. These conditions decrease the volume of blood flowing through the blood vessels, therefore, resulting in low blood pressure.
Arrhythmia
Arrhythmia describes a condition of abnormal heart rhythm. Arrhythmia can occur due to several different heart issues, including scaring of heart tissue from a heart attack, heart disease and high blood pressure. The cells of the heart muscle contract when induced by electrical impulses produced by the sinus node, a group of specialized cells found in the upper right chamber of the heart. These electrical impulses travel through the heart to keep the heart beating at a regular pace, normally 60 to 100 beats per minute, according to the American Heart Association. When the sinus node fails to fire impulses in a normal rhythm, or when something interferes with the pathway of the electrical impulses, arrhythmia can occur. A heart that beats too slow, a condition known as bradycardia, propels less blood into the blood vessels, leading to symptoms, which include dizziness. A heart that beats too fast, a condition known as tachycardia, beats inefficiently, leaving blood in the chambers of the heart, therefore, reducing the volume reaching the brain. This can also cause dizziness.
