Low Blood Pressure Symptoms and Causes Explained

Low blood pressure, medically known as hypotension, is generally defined as a systolic pressure below 90 mmHg and a diastolic pressure below 60 mmHg. It can be caused by various medical conditions, medications, or lifestyle factors. Common symptoms include dizziness, lightheadedness, and even fainting. Additionally, individuals may feel fatigued or experience a decline in memory. These symptoms occur because the brain is often the first organ affected by low blood pressure. Since the brain is located at the top of the body, blood must work against gravity to reach it. This becomes especially noticeable when someone rises quickly from a seated, squatting, or lying position, which can temporarily reduce blood flow to the brain and lead to impaired function, causing dizziness, vertigo, or fainting spells.

Common Causes of Low Blood Pressure

1. Cardiac-Related Factors

Heart conditions such as heart attacks, valve disorders, and irregular heartbeats — whether too fast (tachycardia) or too slow (bradycardia) — can all lead to low blood pressure. These conditions not only cause hypotension but also present symptoms related to the underlying heart issue. For example, individuals may experience chest pain, shortness of breath, or palpitations alongside dizziness or fainting.

2. Medication Side Effects

Certain medications are known to lower blood pressure as a side effect. These include antihypertensive drugs designed to treat high blood pressure, vasodilators that widen blood vessels, and certain psychiatric medications such as antidepressants and anti-anxiety drugs. Additionally, medications used in the treatment of Parkinson's disease can also contribute to hypotension. It's important for patients to monitor their blood pressure when starting or adjusting these types of medications.

3. Reduced Blood Volume

Low blood volume, or hypovolemia, is another major cause of low blood pressure. Conditions that lead to excessive fluid loss — such as severe diarrhea, heavy bleeding, or overuse of diuretics — can significantly reduce the amount of circulating blood in the body. Excessive sweating can also lead to dehydration and a drop in blood pressure. When blood volume decreases, the heart has less fluid to pump, which results in lower pressure within the blood vessels and the associated symptoms of hypotension.