Overview

Isolated diastolic hypertension (IDH) is a health condition characterised by elevated diastolic blood pressure (greater than 90 mmHg), with systolic blood pressure within the normal range (120-129 mmHg).¹ Untreated diastolic hypertension can lead to various health conditions and disorders.² Therefore, it is important to know the standard blood pressure values and measure blood pressure regularly. If self-measurement deviates from these standard values, it is necessary to contact a healthcare provider.

Blood pressure and its measurement components

Pumping the blood around the body involves the contraction of heart muscles, to push out the blood, followed by their relaxation (diastole) occurring repeatedly and continuously. The flow of blood puts pressure on the walls of the blood vessels (blood pressure). Creating this pressure is necessary for blood to be transported around the cardiovascular system so that every part of the body is adequately supplied with the blood and oxygen it carries.

When the blood pressure is being measured, two numbers are displayed on the device, each corresponding to a different component of blood pressure. The top number is the systolic blood pressure, while the bottom number is the diastolic blood pressure.³

• Systolic blood pressure is the force exerted on the arteries during the contraction of the heart muscles when it pumps blood into the arteries
• Diastolic blood pressure is the force that acts on the arteries during the diastole of the heart in other words during its relaxation period before the next contraction³

Healthy blood pressure

Healthy arteries are elastic; they can stretch to allow more blood to flow throughout the vessels if needed. How much they stretch depends on the flow of blood and pressure exerted by the pushing against the walls. To keep the arteries healthy, it is important to maintain the blood pressure within the normal range. A typical blood pressure reading for a healthy individual is usually around 120 mmHg (mmHg is the pressure unit used for blood pressure measurements) for systolic pressure and 80 mmHg for diastolic pressure. However, it might depend on the age, gender, and overall health status of the person being examined.^1,8 

Therefore, blood pressure measurements and their deviations from this standard should always be interpreted in consultation with a healthcare provider.³

High or low blood pressure

Deviations from the typical blood pressure measurement of 120/80 mmHg include both higher values (hypertension) and lower values (hypotension). Both systolic and diastolic blood pressure can be either too high or too low as indicated in the table below. ³

Both hypertension and hypotension are considered health disorders. However, high blood pressure (hypertension) may pose a direct threat to the patient’s life.
Untreated hypertension can cause serious damage to the cardiovascular system including the heart. It can harden the arteries and blood vessels, blocking the flow of blood and subsequently causing an irregular heartbeat, a heart attack (where the blood supply to the heart is obstructed causing death of heart muscle cells), or heart failure (where the heart cannot pump enough blood to meet the needs of the body). Hypertension might also damage the arteries or result in blood flow to the brain being blocked causing a stroke.⁵

What is isolated diastolic hypertension and who suffers from it?

Isolated diastolic hypertension (IDH) is one of the less common subtypes of high blood pressure (accounting for less than 20% of all cases of hypertension).^{2, 6} It is characterised by an elevated value for the diastolic pressure alongside an optimal or normal value for the systolic blood pressure. The blood pressure exceeds standard values during the period of relaxation but remains within the normal range during heart contractions. A health condition, referred to as high diastolic blood pressure usually involves diastolic blood pressure values greater than 90 mmHg.

According to a recent study, the prevalence of isolated diastolic hypertension decreases with age. For older patients, other types of hypertension are more frequently diagnosed. The patients diagnosed with IDH are more likely to be young men.⁶

As one of the types of hypertension, IDH is also associated with an increased risk of adverse cardiovascular events and it is more likely to be diagnosed in patients who have experienced prior cardiovascular events.⁶

Causes and risk factors

In most cases of hypertension (about 85%), the specific cause of the disorder cannot be determined. In rare cases, it might be the result of another health disorder or disease.⁷  However, many risk factors have been identified that could contribute to developing hypertension. These include a sodium-rich diet (eating too much salt), lack of physical activity, obesity, smoking, and regular alcohol consumption.

Symptoms of hypertension

In cases of severely high blood pressure, individuals might experience headaches, chest or back pain, dizziness, a flushed face, blurred vision, numbness, or weakness. However, mild to moderate diastolic hypertension or general hypertension may not exhibit any symptoms while ‘silently’, slowly, progressively damaging the cardiovascular system. Therefore, the only sure way to identify and diagnose hypertension is by measuring the blood pressure.⁵

Diagnosis and monitoring

Since people suffering from high blood pressure may not develop any symptoms, regular monitoring of blood pressure by measuring it at home can help to alert them to deviations from the standard range of values of blood pressure. If a person observes that their blood pressure exceeds these values, they should contact their healthcare provider.
After consulting with the healthcare provider and confirming the measurements, the patient may be diagnosed with hypertension. If it is only the diastolic blood pressure that is elevated (over 90 mmHg) and the systolic blood pressure is within the normal range (120-130 mmHg), the diagnosis might be limited to isolated diastolic hypertension. However, these values must be discussed with the healthcare provider since they can strongly depend on the individual health status of the patient and can vary according to multiple factors.^{1, 8}
In the case of a diagnosis of hypertension, the patient will likely be prescribed appropriate medications for lowering blood pressure and be advised to follow a healthy and active lifestyle. The patient should continue self-monitoring their blood pressure and maintain contact with the healthcare provider.

Methods of IDH treatment

Due to the low prevalence of IDH compared to other types of hypertension, there are no therapeutic methods designed specifically for IDH treatment. The patients diagnosed with this disorder are usually included in the overall category of hypertensive patients and are treated similarly.⁶  There are no specific medications for the treatment of isolated diastolic hypertension. Therefore, therapeutics for the treatment of general hypertension are applied.

The most common classes of therapeutics used in cases of high blood pressure are diuretics, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and calcium channel blockers.⁹ Each class has a different mechanism of action to lower blood pressure and the medications must be chosen individually for each patient by a healthcare provider.

How to manage IDH

Pharmaceuticals are not the only way to manage IDH; lifestyle modifications also play a crucial role in this process. A healthy diet, engaging in regular physical activity, improving sleep, stress management, cessation of smoking, and reducing alcohol consumption might bring significant improvement to the patient’s condition. Lifestyle changes can be implemented alongside medications to amplify their positive effect on the patient’s condition. They may not only help with high blood pressure management but also improve the overall health of an individual.

Summary

Diastolic blood pressure (the number usually displayed at the bottom of the blood pressure monitor) is a measure of the force exerted by the blood on the arteries during the time of relaxation (diastole) of heart muscles in between the heart muscle contractions. 

The term isolated diastolic hypertension refers to a health condition characterised by an increased value of diastolic blood pressure while systolic blood pressure is within the normal range. This uncommon type of hypertension is more likely to be diagnosed among young men who have experienced cardiovascular adverse effects previously.

Self-monitoring of blood pressure can potentially be lifesaving because hypertension usually does not produce any noticeable symptoms. Taking the blood pressure at home is useful for diagnosing isolated diastolic hypertension. However, the values recorded by measurements performed at home must be interpreted by a healthcare provider to confirm the condition and diagnosis.

Medications are available that can be prescribed by a healthcare provider for the treatment of hypertension. However, other methods for improving the individual’s health condition, including a healthy diet, regular physical activity, stress management, or smoking cessation, can also be applied and supported professionally.