Blood pressure indicates overall health, reflecting the force with which blood circulates through the arteries. While high blood pressure (hypertension) is often discussed, low blood pressure (hypotension) also requires attention. Understanding what constitutes low blood pressure is important for recognizing potential health implications.
Decoding Blood Pressure Readings
Blood pressure measurements consist of two numbers, expressed in millimeters of mercury (mmHg). The first number, systolic pressure, represents the force exerted on artery walls when the heart contracts and pumps blood. The second number, diastolic pressure, measures the pressure in the arteries when the heart rests between beats. For most adults, a blood pressure reading below 120/80 mmHg is considered within a normal range.
These two values provide a comprehensive picture of the circulatory system’s function. Blood pressure naturally fluctuates throughout the day due to factors like activity levels, emotional states, and sleep. A consistent reading within the normal range indicates efficient blood flow without undue strain on the heart or vessels.
What Defines Low Blood Pressure
Hypotension is defined as a blood pressure reading below 90/60 mmHg. This threshold applies to resting blood pressure. While these numbers serve as a guideline, what is considered “too low” can vary among individuals.
Some people naturally have blood pressure readings consistently below 90/60 mmHg without experiencing symptoms. In such cases, this lower reading may be normal for their body. However, for others, even a slight drop in blood pressure, such as a 20 mmHg fall in systolic pressure, can lead to noticeable symptoms. Therefore, the presence of symptoms alongside low readings is a significant factor in determining if hypotension requires medical attention.
Common Symptoms and Underlying Causes
When blood pressure drops too low, the body’s organs may not receive adequate blood flow, leading to various symptoms. Common indicators of hypotension include:
- Dizziness
- Lightheadedness
- Fainting
- Blurred vision
- General weakness or fatigue
- Confusion
- Nausea
- Rapid, shallow breathing
Several factors can contribute to low blood pressure. Dehydration, which reduces blood volume, is a frequent cause. Certain medications, such as those prescribed for high blood pressure, depression, or erectile dysfunction, can also lower blood pressure as a side effect. Underlying medical conditions like heart problems, endocrine disorders (e.g., an underactive thyroid), or severe infections (sepsis) can also lead to hypotension. Sudden changes in body position, such as standing up quickly, can cause a temporary drop in blood pressure known as orthostatic hypotension.
When to Seek Medical Guidance
Individuals should seek medical guidance if they consistently experience symptoms associated with low blood pressure, even if their readings are only slightly below the normal range. It is particularly important to consult a healthcare professional if symptoms like dizziness or fainting are new, sudden, or occur frequently. These symptoms can sometimes indicate an underlying health issue that requires diagnosis and management.
Immediate medical attention is needed if severe symptoms of hypotension occur, such as loss of consciousness, confusion, cold and clammy skin, or a rapid and weak pulse. These signs could indicate a serious condition like shock, where organs are not receiving enough blood. Even if readings are not extremely low, persistent or concerning symptoms should prompt a discussion with a doctor to determine the cause and appropriate course of action.