Blood pressure is a measurement of the force blood exerts against the walls of the arteries. This force is important for ensuring that blood circulates effectively throughout the body, delivering oxygen and nutrients to tissues and organs. A blood pressure reading consists of two numbers: the systolic pressure, which is the upper number, and the diastolic pressure, which is the lower number. The systolic pressure reflects the force when the heart beats and pumps blood, while the diastolic pressure indicates the pressure in the arteries when the heart rests between beats.
Defining Low Diastolic Blood Pressure
Normal blood pressure is below 120/80 mmHg. Low blood pressure, also known as hypotension, is a reading below 90/60 mmHg. Specifically, low diastolic blood pressure occurs when the bottom number is unusually low. While a healthy diastolic reading is often below 80 mmHg, a reading of 60 mmHg or less is considered low. In some instances, the diastolic pressure can be low even when the systolic pressure remains within a normal range, a condition referred to as isolated diastolic hypotension. This condition highlights reduced pressure in the arteries during the heart’s relaxation phase, which is when the heart muscle itself receives its blood supply.
Common Symptoms to Watch For
Low diastolic blood pressure can cause several noticeable symptoms. Dizziness, lightheadedness, blurred vision, tunnel vision, and confusion often result from insufficient blood flow to the brain. Fainting, or syncope, may occur if brain blood flow significantly decreases.
Individuals might also experience fatigue, weakness, or nausea, possibly due to inadequate blood flow to the digestive system. Other physical signs include cold, clammy, or pale skin, and rapid, shallow breathing.
Chest pain (angina) or heart failure symptoms like shortness of breath and lower extremity swelling may develop if the heart muscle itself is not receiving enough blood during the diastolic phase.
Factors Contributing to Low Diastolic Blood Pressure
Several factors can contribute to low diastolic blood pressure. Dehydration is a common cause, as it reduces blood volume and pressure. Certain medications can also lower diastolic pressure, including diuretics, some heart medications (e.g., alpha-blockers, beta-blockers), and antidepressants. Age is another factor, as stiffening arteries can cause systolic pressure to rise while diastolic pressure decreases.
Underlying medical conditions also play a role. These include heart conditions like valve problems, a slow heart rate, or heart failure. Endocrine disorders such as adrenal insufficiency or hypothyroidism can impact blood pressure regulation. Severe infections, especially sepsis, and allergic reactions like anaphylaxis, can cause a sudden and significant drop in blood pressure.
Knowing When to Consult a Doctor
While low blood pressure does not always cause noticeable problems, seeking medical attention is important if symptoms are present. You should consult a healthcare provider if you consistently experience symptoms such as dizziness, lightheadedness, or fainting. Even if your symptoms are mild, consistently low diastolic readings should prompt a discussion with a healthcare professional to determine if there are any underlying conditions.
Immediate medical evaluation is necessary for severe symptoms, including chest pain, difficulty breathing, or loss of consciousness. A weak, rapid pulse, shallow breathing, or confusion are also signs that warrant urgent medical care. This article offers general information and should not be considered a substitute for personalized medical advice from a qualified healthcare provider.