High blood pressure, also known as hypertension, is a condition in which both systolic and diastolic blood pressure levels are higher than normal. Though less common, it’s also possible to have high diastolic blood pressure levels and normal systolic blood pressure levels. This is also referred to as isolated diastolic hypertension (IDH).
Understanding the risk factors of IDH can help to understand whether or not you may be at risk for the condition. Though experts aren’t sure what causes IDH, there are certain factors associated with the condition that may increase the risk, including age, sex, physical activity, and body mass index (BMI).
What is Diastolic Blood Pressure?
Blood pressure is the force that blood exerts on the arteries when it travels through them. A blood pressure reading is usually recorded as two numbers, with one number on top of the other. Diastolic blood pressure is the second or bottom number on a blood pressure reading. It measures how much force is exerted against the arterial walls when the heart is resting in between beats.
Normal Diastolic Blood Pressure Levels
Blood pressure measurements are taken in units of mercury (mm Hg). According to the American Heart Association (AHA), normal diastolic blood pressure levels are less than 80 mm Hg.
In order to know your diastolic blood pressure levels, you need to have your blood pressure tested. You can have your blood pressure tested by your healthcare provider, at a pharmacy store, or at home by using a blood pressure monitor.
Causes of High Diastolic Blood Pressure
High blood pressure, also called hypertension, is when both the diastolic blood pressure and the systolic blood pressure are higher than normal. But high diastolic blood pressure levels that occur when systolic blood pressure levels are normal can indicate a condition called isolated diastolic hypertension (IDH). IDH is less common than combined systolic-diastolic hypertension and is more commonly seen in young and middle-aged adults.
Experts aren’t sure what causes IDH, but there are some factors that may contribute to its development or the development of hypertension (when both systolic and diastolic blood pressure levels are elevated).
High sodium intake
Research suggests that salt intake and eating habits may not have an impact on the development of IDH. However, high sodium intake is associated with an increased risk of developing hypertension.
Increased body mass index (BMI) is associated with the development of IDH and hypertension. Maintaining a healthy weight may help to keep your blood pressure levels in a healthy range.
Anxiety and stress
There isn’t sufficient evidence to suggest that anxiety and stress can cause IDH. But, studies show that anxiety and chronic stress can increase the risk of hypertension. Both anxiety and stress can trigger an increase in a protein hormone called angiotensin II, which narrows blood vessels and makes it harder for the heart to pump blood through them. Chronic anxiety can also lead to reduced vascular variability, which makes it harder for blood vessels to widen and narrow effectively. Over time, this can also lead to high blood pressure.
Alcohol consumption is associated with the development of IDH. In general, drinking alcohol can raise both systolic and diastolic blood pressure levels. If you’re at risk of hypertension or IDH, it’s important to limit your alcohol consumption and only drink in moderation.
Some medications, like over-the-counter (OTC) pain relievers (like nonsteroidal anti-inflammatory drugs), birth control pills, antidepressants, and medicines given to people who just got an organ transplant, can cause high blood pressure. If you’re concerned that a medication you’re taking may be causing your high blood pressure, be sure to review your existing medications with a healthcare provider.
There are several risk factors associated with high diastolic blood pressure levels and IDH. These factors include:
- Family history of hypertension
- Alcohol consumption
- Young age (less than 50 years old)
- Male gender
- Increased blood glucose
- Increased body mass index (BMI)
- Type 2 diabetes
- High triglyceride levels
- Previous cardiovascular events
- Sedentary lifestyle
As with hypertension, high diastolic blood pressure rarely causes noticeable symptoms. This can make it especially difficult to diagnose and treat. In fact, one study found that only 10% of those with IDH were aware that they had high blood pressure levels.
IDH should be treated in a way that is unique to each person and based on their health condition and what caused it. In general, many experts recommend foregoing treatment in younger patients if the risk of cardiovascular events is low, because certain medications used to lower blood pressure can lead to serious adverse events. However, when medication is appropriate, calcium channel blockers are frequently used, followed by angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and diuretics.
High diastolic blood pressure cannot always be prevented, but some strategies can help to lower your risk of IDH and hypertension:
- Maintain a healthy weight
- Get regular physical exercise
- Quit smoking
- Limit or avoid drinking alcohol
- Eat a healthy and balanced diet
- Practice stress management
- Treat chronic anxiety (if present)
When to See a Medical Provider
If you have a family history of high blood pressure or IDH, talk to your healthcare provider about blood pressure screening and how often to do this.
If you experience any of the signs of severely high blood pressure, seek immediate medical attention:
- Blurred vision
- Chest pain
- Bloody nose
- Tingling sensation
- Numbness in the extremities
- Nausea and vomiting
- Not responding to stimuli
- Severe headache
- Shortness of breath
A hypertensive emergency can cause death or permanent damage to the brain, heart, or kidneys.
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Current approach to isolated diastolic hypertension. (2020).
Isolated Diastolic Hypertension in the IDACO Study: An Age-Stratified Analysis Using 24-Hour Ambulatory Blood Pressure Measurements. (2021).
Prevalence, Awareness, and Treatment of Isolated Diastolic Hypertension: Insights From the China PEACE Million Persons Project. (2019).
Prevalence of isolated diastolic hypertension and associated risk factors among adults in Kanpur, India. (2012).
Understanding Blood Pressure Readings. (n.d.).