- Hypotension, or low blood pressure, is a condition in which the force of blood circulating through the arteries is lower than what is considered normal.
- Blood pressure is measured in millimeters of mercury (mmHg) and expressed as two numbers: systolic (pressure during heartbeats) over diastolic (pressure between heartbeats).
- A typical healthy adult blood pressure is around 120/80 mmHg, and hypotension is often defined as a reading lower than 90/60 mmHg. While many people with low blood pressure experience no problems and may even benefit from it in terms of reduced risk of cardiovascular disease, in others it can cause troubling symptoms or indicate an underlying health issue.
- There are several forms of hypotension, each with distinct causes and implications. Orthostatic hypotension occurs when blood pressure drops suddenly upon standing from a sitting or lying position, often leading to dizziness, lightheadedness, or fainting. This is due to impaired regulation of blood flow and can be more common in older adults, people with dehydration, or those taking certain medications. Another form, postprandial hypotension, happens after eating, when blood pools in the digestive tract. Severe or acute hypotension may arise from shock, blood loss, severe infection (septic shock), or allergic reactions (anaphylaxis), and can be life-threatening because it deprives vital organs of adequate blood supply.
- The symptoms of hypotension vary depending on its severity and cause. Mild or chronic low blood pressure may go unnoticed, but when it is symptomatic, individuals may experience dizziness, blurred vision, fainting, nausea, fatigue, or difficulty concentrating. In dangerous cases, hypotension can lead to confusion, rapid and shallow breathing, weak pulse, and loss of consciousness, signaling inadequate perfusion of the brain and other critical organs.
- The causes of hypotension are wide-ranging. They may include dehydration, prolonged bed rest, heart problems (such as arrhythmias or heart failure), endocrine disorders (like Addison’s disease or hypothyroidism), severe infections, pregnancy, or adverse effects of medications such as diuretics, beta-blockers, or antidepressants. Lifestyle factors like alcohol consumption or overheating can also contribute. Diagnosis typically involves measuring blood pressure multiple times, reviewing medical history, conducting blood tests, and sometimes performing tilt-table testing to evaluate how the body responds to changes in posture.
- Treatment depends on whether hypotension is benign or harmful. For many people, no treatment is necessary, particularly if low blood pressure does not cause symptoms. When intervention is needed, strategies may include increasing fluid and salt intake (under medical supervision), wearing compression stockings, adjusting medications, or using drugs that raise blood pressure. In emergencies, intravenous fluids, vasopressors, or rapid interventions to address underlying causes (such as treating infection or controlling bleeding) may be lifesaving.
