What is Low Blood Pressure?

Low blood pressure, also known as hypotension, is generally defined as a systolic blood pressure below 90 mmHg or a diastolic pressure under 60 mmHg in adults. However, whether low blood pressure requires treatment depends on its impact on a person's quality of life and overall health. Some young individuals, especially those with a lean build or a sedentary lifestyle, may naturally have blood pressure readings around 90/60 mmHg or even slightly lower. If there are no symptoms such as dizziness or fatigue, this is often classified as physiological hypotension and typically does not require medical intervention.

Common Causes of Low Blood Pressure

Low blood pressure can arise from a variety of underlying conditions. In clinical settings, it is often linked to severe heart disease, serious infections, physical trauma, or shock — including hemorrhagic shock, traumatic shock, or cardiogenic shock. These conditions can lead to inadequate blood flow to vital organs such as the brain, heart, and kidneys.

Symptoms of Clinically Significant Hypotension

When blood pressure drops to a level that affects organ function, patients may experience symptoms like dizziness, weakness, blurred vision, shortness of breath, chest discomfort, palpitations, and reduced urine output. In extreme cases, it can progress to a state of shock, which is a life-threatening emergency requiring immediate medical attention.

Understanding Relative Hypotension

It's also important to consider the concept of relative hypotension. This occurs when a person's blood pressure drops significantly from their usual baseline, even if the new readings are still above the standard thresholds of 90/60 mmHg. For example, someone whose normal blood pressure is 140/80 mmHg may experience symptoms of hypotension if their pressure suddenly drops to 100/70 mmHg. This type of blood pressure change can still be clinically significant and warrants careful evaluation by a healthcare professional.