Hypertension, commonly known as high blood pressure, affects many adults globally. It often progresses without symptoms, earning it the moniker “silent killer.” The lower number in blood pressure readings, diastolic blood pressure, is an important aspect of cardiovascular health. Understanding its causes is important for managing this condition and preventing complications. This article explores the causes of diastolic hypertension, from habits to medical issues.
Understanding Diastolic Blood Pressure
Blood pressure is measured as two numbers: systolic over diastolic. The diastolic reading, the lower number, represents the pressure within your arteries when your heart relaxes and fills with blood between beats. A healthy diastolic reading typically falls below 80 millimeters of mercury (mmHg).
A diastolic reading consistently at or above 80 mmHg indicates elevated diastolic pressure. For example, 120/80 mmHg shows a diastolic pressure of 80 mmHg, the upper limit of normal. Readings from 120/80 mmHg to 129/80 mmHg are categorized as elevated blood pressure, while 130/80 mmHg or higher indicates hypertension. Monitoring both systolic and diastolic numbers provides a comprehensive picture of cardiovascular health.
Primary Factors Contributing to Diastolic Hypertension
Many cases of diastolic hypertension develop without a single identifiable underlying medical condition, often linked to a combination of lifestyle choices and inherent factors. Consuming excessive sodium, frequently found in processed foods, can lead to fluid retention, increasing blood volume and subsequently elevating diastolic pressure. Conversely, insufficient potassium intake, which helps balance sodium levels, can also contribute to higher readings. A diet rich in unhealthy saturated and trans fats may promote arterial stiffness, making it harder for arteries to relax and accommodate blood flow between heartbeats.
A sedentary lifestyle contributes to weight gain and reduced cardiovascular fitness, directly affecting diastolic readings. Being overweight or obese places additional strain on the cardiovascular system, requiring the heart to work harder to circulate blood, which can lead to increased pressure during the relaxation phase. Chronic stress triggers the release of hormones like cortisol and adrenaline, temporarily narrowing blood vessels and increasing heart rate, potentially leading to sustained diastolic elevation.
Excessive alcohol consumption can damage blood vessel walls and interfere with the body’s ability to regulate blood pressure, contributing to both systolic and diastolic increases. Smoking introduces harmful chemicals into the bloodstream that stiffen arteries and reduce their elasticity. A family history of hypertension indicates a genetic predisposition, meaning individuals may be more susceptible to elevated diastolic pressure. As individuals age, arteries tend to stiffen and become less elastic, a process known as arteriosclerosis, which can lead to higher diastolic blood pressure readings.
Secondary Medical Conditions and Medications
In some instances, elevated diastolic blood pressure stems from an identifiable underlying medical condition or the use of certain medications. Kidney diseases, such as renal artery stenosis or chronic kidney disease, can impair the kidneys’ ability to regulate fluid and electrolyte balance, leading to increased blood volume and elevated diastolic pressure. For example, narrowing of the renal arteries reduces blood flow to the kidneys, prompting them to release hormones that raise blood pressure.
Thyroid disorders, particularly hypothyroidism (an underactive thyroid), can slow metabolic processes and affect heart function, sometimes resulting in increased peripheral vascular resistance and higher diastolic readings. Tumors of the adrenal glands, such as pheochromocytoma (producing excess adrenaline) or aldosteronism (overproducing aldosterone), can directly cause increases in blood pressure, including the diastolic component. Sleep apnea, where breathing repeatedly stops and starts during sleep, leads to intermittent drops in oxygen and increases in carbon dioxide, triggering stress responses that elevate blood pressure during both waking and sleeping hours.
Aortic stiffness, where the body’s largest artery becomes rigid, directly impacts how effectively blood is accommodated during the heart’s relaxation phase, often leading to isolated diastolic hypertension. Certain medications can also have an unintended effect on blood pressure. Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause fluid retention and affect kidney function, while decongestants narrow blood vessels. Some antidepressants, oral contraceptives, and corticosteroids can also influence blood pressure regulation, leading to elevated diastolic readings. Illicit drug use, such as cocaine and amphetamines, can cause significant increases in blood pressure by constricting blood vessels and overstimulating the cardiovascular system.