Overview

Hypotension, commonly called low blood pressure, refers to blood pressure readings lower than the range that reliably supplies organs with oxygenated blood. For many adults, values below a systolic pressure of about 90 mmHg or a diastolic pressure below about 60 mmHg are considered low, although what is problematic varies by individual. Some people—such as young healthy athletes—have persistently low readings without symptoms and require no treatment.

Causes and types

Low blood pressure can arise from many mechanisms. It may reflect reduced blood volume, weakened heart pumping, dilation of blood vessels, or abnormal autonomic nervous system control. Common patterns include:

  • Orthostatic hypotension: a drop in pressure when standing up, often causing dizziness.
  • Postprandial hypotension: decline in pressure after meals, more common in older adults.
  • Neurally mediated hypotension: inappropriate reflex responses, frequently affecting younger people after prolonged standing.
  • Shock and severe hypotension: from major blood loss, sepsis, or heart failure; a medical emergency.

Symptoms and possible complications

Symptoms occur when blood flow to the brain or other organs is inadequate. Typical complaints include lightheadedness, blurred vision, weakness, nausea, confusion, and fainting (syncope). Recurrent or severe hypotension can increase the risk of falls and organ injury; prolonged very low pressure may cause acute kidney injury or damage to the heart and brain.

Diagnosis

Diagnosis begins with accurate blood pressure measurement in different positions (lying, sitting, standing) and correcting for cuff size and technique. Ambulatory or home monitoring can capture fluctuations over the day. Further testing may include blood tests, electrocardiography, echocardiography, autonomic function tests such as a tilt-table study, and evaluation for contributing medications or endocrine disorders.

Treatment and management

Management targets the underlying cause and symptom relief. General measures often recommended are gradual posture changes, increased dietary salt and fluid intake when appropriate, compression stockings, and physical counterpressure maneuvers (leg crossing, calf tensing). When conservative measures are insufficient, clinicians may prescribe medications such as fludrocortisone or alpha-agonists to raise blood pressure. In emergency settings, intravenous fluids or vasopressors are used.

When to seek medical care

Seek prompt evaluation for sudden or severe symptoms, fainting, chest pain, shortness of breath, or signs of shock (cold clammy skin, rapid weak pulse, confusion). Persistent symptomatic hypotension or suspicion of an underlying disease warrants medical follow-up. For general information and clinical guidance, consult a reliable resource such as a medical reference.