Low blood pressure, also known as hypotension, is a condition in which the blood pressure is lower than normal. Normal blood pressure is considered to be between 120/80 mmHg and 140/90 mmHg. Blood pressure is measured in millimeters of mercury (mmHg) and is recorded as two numbers: systolic blood pressure (the top number) and diastolic blood pressure (the bottom number). Hypotension is defined as having a systolic blood pressure of less than 90 mmHg or a diastolic blood pressure of less than 60 mmHg.
Low blood pressure can be caused by a number of factors, including dehydration, blood loss, certain medications, and medical conditions such as heart disease and diabetes. Symptoms of low blood pressure can include dizziness, lightheadedness, fainting, nausea, and blurred vision. In severe cases, low blood pressure can lead to shock and even death.