Blood pressure is a measurement of the force blood exerts against the walls of your arteries. It is expressed as two numbers: systolic and diastolic. The systolic pressure, the upper number, reflects the pressure when your heart beats and pushes blood out. The diastolic pressure, the lower number, indicates the pressure in your arteries when your heart rests between beats and refills with blood. While both numbers are important, a low diastolic reading can signal an underlying health concern.
Understanding Low Diastolic Pressure
A healthy blood pressure reading is below 120/80 mmHg. Low blood pressure, or hypotension, is broadly defined as a reading below 90/60 mmHg. Specifically, low diastolic pressure occurs when the bottom number falls below 60 mmHg.
The diastolic phase is particularly important because it is when the heart muscle itself receives oxygen-rich blood through the coronary arteries. This resting phase allows the heart to replenish its own blood supply. When diastolic pressure is too low, the heart may not receive adequate blood flow, potentially affecting its function and the perfusion of other organs throughout the body.
Common Causes
Several factors can contribute to low diastolic pressure. Dehydration is a common cause, as insufficient fluid intake or excessive fluid loss can reduce blood volume, leading to lower blood pressure overall. Certain medications can also affect diastolic pressure; for instance, diuretics, antidepressants, and some blood pressure medications like alpha-blockers are known to lower it.
Underlying medical conditions also contribute. Heart conditions, such as heart valve problems, heart failure, or a slow heart rate, can lead to lower blood pressure. Endocrine disorders, like adrenal insufficiency or hypothyroidism, and severe infections can also contribute to low diastolic readings. Additionally, aging can cause arteries to become stiffer, sometimes resulting in a lower diastolic pressure, even if the systolic pressure remains stable or increases.
Recognizing the Signs
When diastolic pressure is low, the body may not receive enough blood flow, leading to various symptoms. Common indicators include dizziness and lightheadedness, especially when moving from a sitting or lying position to standing. Individuals might also experience fatigue, a general feeling of weakness, or blurred vision.
Fainting is another possible sign, occurring if the drop in blood flow to the brain is significant. Some people may also report nausea, confusion, or cold, clammy skin. Not everyone with low diastolic pressure will experience noticeable symptoms, and the severity varies among individuals.
Potential Health Implications
Low diastolic pressure can pose health risks because it impacts the blood supply to the heart and other vital organs. If this pressure is too low, the heart muscle may not receive enough oxygenated blood, leading to inadequate coronary artery filling.
Over time, this reduced blood flow can weaken the heart and lead to conditions such as heart failure. Beyond the heart, insufficient blood perfusion can also affect the brain, causing confusion or an increased risk of falls, particularly in older adults. Prolonged low diastolic pressure might also impact kidney function due to reduced blood flow to these organs.
When to Consult a Doctor
It is advisable to consult a healthcare professional if you frequently experience symptoms associated with low diastolic pressure, such as persistent dizziness, lightheadedness, or fainting spells. You should also seek medical attention if home blood pressure readings consistently show a diastolic number below 60 mmHg, especially if accompanied by symptoms. A sudden, significant drop in blood pressure that causes severe symptoms like chest pain, extreme weakness, or confusion warrants immediate medical evaluation.
A doctor will assess your overall health, review any medications you are taking, and may suggest lifestyle adjustments. They might also perform additional tests, such as blood or urine tests, or an electrocardiogram, to identify any underlying causes. The goal is to determine the reason for the low reading and develop an appropriate management plan to ensure your heart and other organs receive adequate blood flow.