A 24-hour blood pressure monitor, also known as an ambulatory blood pressure monitor, is a device that automatically tracks your blood pressure over a period of 24 hours. The monitor measures both your systolic blood pressure (the pressure caused by your heart contracting and pumping blood around your body) and your diastolic blood pressure (the pressure in your heart’s arteries when your heart rests between heartbeats).Prolonged monitoring over a 24 hour period allows your doctor to see a more accurate representation of your blood pressure when you are performing your everyday activities. Blood pressure measurements will betaken automatically throughout the day and night, allowing your doctor to assess any changes or abnormalities in your blood pressure. Having undiagnosed high blood pressure (hypertension) or low blood pressure (hypotension) can be dangerous. If left undetected or uncontrolled, it can have serious consequences, including a stroke, kidney failure, a heart attack or an aneurysm. Having a blood pressure monitor can result in early diagnosis and more effective treatment.
A 24-hour blood pressure monitor can assess how changes in your blood pressure correlate with your daily activities and sleep patterns. It can detect abnormal changes in your blood pressure that may not be noticed by you and cannot be detected while you are sitting down in a doctor’s office. For example, you may experience abnormal changes in your blood pressure at certain times of the day or when doing certain activities. For the majority of people, their systolic blood pressure decreases by approximately 20% while they sleep. However, for some people, their blood pressure may not drop while they sleep and may rise instead.
A 24-hour monitor is also used to ensure you are not experiencing white coat syndrome. It consists in a blood pressure increase when you are in a clinical setting. Many people feel stress or anxiety when visiting the doctor, and this can result in inaccurate blood pressure readings. With up to 20% of people experiencing whitecoat syndrome, your doctor is unlikely to make a diagnosis of hypertension without first doing a 24-hour blood pressure monitor.
Some other reasons why your doctor may have recommended a24-hour blood pressure monitor include:
· To establish a suspected diagnosis of hypertension.
· To determine how well antihypertensive drugs are working.
· To assess your blood pressure while you are sleeping.
· To predict the likelihood of cardiovascular disease or cerebrovascular disease for people already diagnosed with hypertension.
· To assess hypertension linked with pregnancy.
· If you have borderline hypertension.
· To determine whether medication changes have impacted your blood pressure.
· If you have experienced fainting episodes or hypotension.
A blood pressure cuff is fitted to your arm and connected to an automated inflating device. The cuff will be connected by a tubular wire toa portable device that is attached to a belt worn on your body. The cuff will take automated readings at various intervals over a 24 hour period, including whilst you are sleeping.
To take a reading, the cuff will inflate, squeezing your upper arm. This may feel uncomfortable and depending on the positioning of your arm, you may feel slight pain.
Just before the machine begins taking a reading, it will make a beeping noise to pre-warn you. When you hear the beep, where possible, you should:
· Ensure the wire isn’t twisted or bent.
· Sit down.
· Keep your arm still.
· Refrain from talking or crossing your legs.
Once the device has finished taking a reading, the cuff will automatically deflate. Your blood pressure readings will be collected automatically and after 24 hours, you should remove the cuff and return the equipment to us.
The readings will be uploaded onto a computer and will be carefully analysed. Your heart rate distribution and blood pressure statistics will be analysed, and we will look at your day-time average reading, your night-time average reading and your 24-hour average. We will also look at any readings that were unusually high or low.
There is no one specific cause of high blood pressure, instead, there are several different risk factors that could increase your likelihood of developing hypertension. This includes:
· A family history: If a close family member, such as your parents or siblings, has hypertension, this increases your likelihood.
· Your age: The risk of hypertension increases as you age.
· Being overweight: If you are over weight, the amount of blood flowing through your blood vessels increases and the pressure on your artery walls also increases.
· Eating too much salt: Sodium causes your body to retain fluid which can increase your blood pressure.
· Smoking: Tobacco can damage the lining of your artery walls.
· Not being physically active: Lack of exercise can result in a higher heart rate and higher blood pressure.
· High stress levels: This can result in a temporary increase in your blood pressure.
· A hormonal problem: This could include pheochromocytoma.
· Certain chronic conditions: Such as Conn’s disease, kidney disease and diabetes.
· The contraceptive pill: Hormones in the pill can result in a narrowing of your blood vessels and an increase in your blood pressure.
You may be referred for a 24-hour blood pressure monitor for several reasons:
· If you experience symptoms such as headaches, dizziness or shortness of breath.
· If a previous blood pressure reading was high.
· To assess whether your hypertension is mild, moderate or severe.
· To determine the correct dosage of medication you require.
· To assess the effectiveness of blood pressure medication.