Low diastolic blood pressure is when blood pressure between heartbeats is lower than it should be. Blood pressure is the force that blood exerts against the arteries as the heart pumps it around the body.
This article will take a closer look at low diastolic blood pressure, including its causes, symptoms, and treatments.
Systolic blood pressure: This is the top number, and is the higher of the two. It measures how much pressure the blood applies to the artery walls when the heart beats.
Diastolic blood pressure: This is the lower number, which shows the pressure that the blood applies to the artery walls when the heart rests between beats.
A blood pressure reading will show the systolic blood pressure number first, and diastolic blood pressure second. A doctor will assess a person’s blood pressure by considering both numbers. In most adults, a healthy reading is usually less than 120/80 mm Hg. Low blood pressure, or hypotension, is blood pressure that is below 90/60 mm Hg.
Low diastolic blood pressure, or isolated diastolic blood pressure, is when the diastolic blood pressure falls below 60 mm Hg, while the systolic blood pressure remains at a normal level.
When the heart rests in between beats, the coronary arteries receive and supply the heart with oxygen-rich blood. If the diastolic pressure is too low, the heart will not get the amount of blood and oxygen it needs. This may cause the heart to weaken over time.
Older people who take medications for high blood pressure are at higher risk of experiencing lower diastolic blood pressure.
Some people naturally have lower blood pressure, which causes them no health problems. Other people may experience a drop in blood pressure due to an issue with their health. These issues can include:
Some people may also experience neurally mediated hypotension, where blood pressure drops after standing for long periods
Low blood pressure can also be due to:
- prolonged bed rest
- high salt intake
Moving from lying down to standing up can lead to a dip in blood pressure. This may usually only lasts for a few seconds.
A dip in blood pressure can also happen to some people after they eat a meal. According to the Journal of Geriatric Cardiology, this mostly occurs in older adults, those with high blood pressure, or people with Parkinson’s disease.
A person who has low diastolic blood pressure may feel dizzy and tired. They may also fall more often. This can be particularly dangerous in older adults.
Usually, low blood pressure will not cause any issues. Within certain limits, it can be healthy to have low blood pressure. Low blood pressure becomes a problem when other symptoms are present, such as:
- feeling lightheaded
- unusual thirst or dehydration
- feeling weak
- blurry vision
- cold, clammy, pale skin
- rapid, shallow breathing
Symptoms may subside when sitting down or resting. If blood pressure drops too low, the body’s vital organs will not get enough nutrients and oxygen to function correctly. This could lead to the body going into shock. If this happens, a person should immediately seek medical attention.
To determine if a person has low diastolic blood pressure, a doctor will use a sphygmomanometer, a device that straps around the person’s arm, to take a blood pressure reading. A doctor will consider a diastolic reading below 60 mm Hg to be too low.
A doctor can carry out further tests to identify the cause of a person’s low blood pressure, including:
- blood or urine tests
- an electrocardiogram to read the heart’s electrical signals to detect the rhythm and any abnormalities
- an echocardiogram to show detailed images of the heart
- a stress test, where a person undergoes heart monitoring while exercising
If the person tested finds that they faint often, the doctor may use a tilt table test. They use straps to secure the person to the table as it is tilted at different angles to see how the body reacts.
There are numerous treatments options that can help improve low diastolic blood, such as
- speaking to a doctor about changing certain medications
- wearing compression stockings, which improve circulation
- eating more salty foods or drinking more caffeine to temporarily increase blood pressure temporarily
Doctors may prescribe drugs, such as fludrocortisone and midodrine, to treat certain kinds of low blood pressure. However, there are currently no medicines available to treat low diastolic blood pressure.
Given that age can be a significant cause of low diastolic blood pressure, it is not always possible for a person to prevent it.
However, maintaining a healthy weight, eating a balanced diet, and exercising regularly can help keep blood pressure levels stable, as well as help keep the heart healthy.
There are several lifestyle changes that someone with low diastolic blood pressure can make to manage their condition:
- stopping smoking
- lowering alcohol consumption
- eating smaller meals
- drinking more water
- not sitting or standing still for long periods
- getting up slowly when sitting or lying down
In general, low blood pressure will not cause additional health issues. However, it can increase the risk of falls, which is particularly dangerous for older adults.
People with low diastolic blood pressure may also have an increased risk of heart failure, so people must manage it as well as possible.
Symptoms of heart failure include:
- shortness of breath
- persistent cough
- swelling in the lower body
Anyone experiencing more than one of these symptoms should seek immediate medical attention. Researchers found a significant increase in the risk of heart damage in people over 60 who had very low diastolic blood pressure.
Changes in diet, exercise, and lifestyle can all help increase low diastolic blood pressure. People with low diastolic blood pressure should visit their doctor regularly. This ensures that the doctor finds any new issues caused by low blood pressure quickly.