Hypotension

Hypotension, or low blood pressure, is a cardiovascular condition in which blood pressure falls abnormally low, generally defined as a systolic reading under 90 mmHg or a diastolic reading under 60 mmHg, though in practice it is only treated as a problem once it causes noticeable symptoms. Common symptoms include dizziness, lightheadedness, confusion, tiredness, weakness, headache, blurred vision, nausea, and sometimes fainting, ranging from mild to severe depending on the cause. It can result from strenuous exercise, excessive heat, low blood volume, hormonal changes, widening of blood vessels, anemia, vitamin B12 deficiency, anaphylaxis, heart problems, endocrine problems, or certain medications. Severely low blood pressure can starve the brain and other organs of oxygen and nutrients, producing the life-threatening state of shock, though hypotension is generally understood as a physiological state rather than a disease in itself, and some healthy athletes have normally low blood pressure.