Decoding Blood Pressure Readings | Gleneagles Hospitals

Blood pressure is controlled by different systems in the body, including organs, hormones, and nerves. For example, the autonomic nervous system sends out “fight-or-flight” signals that instruct the heart and other bodily systems to raise or lower blood pressure based on the situation.

Measuring blood pressure

Blood pressure measures the force of blood pushing against the walls of your arteries, which carry blood from your heart to the rest of your body.

To measure blood pressure, a doctor or nurse uses a device called a sphygmomanometer. This device has an inflatable cuff and a mercury scale. The cuff is placed around your upper arm and inflated to momentarily stop blood flow, then the air is slowly released.

While releasing the air, the healthcare provider observes the mercury gauge and listens to your arm’s main artery using a stethoscope. They record the systolic pressure (the pressure when the heart beats) when they first hear your heartbeat and the diastolic pressure (the pressure when the heart rests between beats) when the sound disappears.

A digital sphygmomanometer might also be used, which automatically measures your pulse and blood pressure using electronic sensors.

After measuring, they will give you two numbers: the systolic reading first, followed by the diastolic reading:

The first or upper number (systolic): Indicates the pressure when your heart is contracting.
The second or lower number (diastolic): Indicates the pressure when your heart is refilling with blood.

Blood pressure readings are recorded in millimetres of mercury (mmHg). For example, if your systolic pressure is 120 mmHg and your diastolic pressure is 80 mmHg, it will be reported as “120 over 80,” often written as 120/80 mmHg.

Understanding blood pressure readings

Ideal (normal) blood pressure	120/80 mmHg
Low blood pressure (hypotension)	< 90/60mmHg
Elevated blood pressure	Systolic (upper number): 120 – 129 mm Hg Diastolic (lower number): < 80 mm Hg
Stage I hypertension (high blood pressure)	Systolic (upper number): 130 – 139 mm Hg Diastolic (lower number): 80 – 89 mm Hg
Stage II hypertension (high blood pressure)	Systolic (upper number): > 140 mm Hg Diastolic (lower number): > 90 mm Hg
Hypertensive crisis	> 180/120 mm Hg Requires immediate medical attention

You might be curious whether low or high blood pressure is more concerning. Healthcare professionals generally consider chronically low blood pressure dangerous only if it causes noticeable symptoms. On the other hand, high blood pressure, often referred to as a “silent killer,” typically does not present obvious symptoms but can pose serious health risks if not managed properly.

Low blood pressure (hypotension)

Hypotension, the medical term for low blood pressure, occurs when blood circulates through your blood vessels at pressures lower than usual. Low blood pressure is defined as a reading below 90/60 mmHg.

Causes

Dehydration, which reduces blood volume, leading to lower pressure in the arteries
Certain medications like diuretics
Heart conditions that weaken the heart’s ability to pump blood effectively
Endocrine disorders such as adrenal insufficiency
Sudden changes in body position
Prolonged bed rest
Severe infection
Blood loss due to injuries
Severe allergic reactions
Septic shock, toxic shock syndrome, anaphylactic shock, cardiogenic shock

Symptoms

Low blood pressure (hypotension) often does not cause symptoms and usually does not require treatment if symptoms are absent.

However, it can sometimes lead to insufficient blood flow to vital organs, causing symptoms like dizziness, confusion, fainting, fatigue, blurry vision, headaches, nausea, and heart palpitations.

Postural or orthostatic hypotension, a type of low blood pressure that occurs with sudden movements, can cause dizziness or fainting when changing positions, such as standing up quickly. These symptoms usually resolve within a few minutes but become more common with age, increasing the risk of falls.

You should consult a doctor if you constantly experience symptoms of low blood pressure, such as dizziness and fainting.

Diagnosis & Treatment

Low blood pressure is typically diagnosed through medical history, physical examination, and sometimes additional tests.

If a cause for low blood pressure is identified, your doctor will recommend treatment accordingly:

Adjusting your medication or dosage if it is causing a drop in your blood pressure.
If your doctor suspects an underlying issue such as a heart condition, adrenal gland dysfunction, or a nerve disorder is contributing to your low blood pressure, you might be referred to a specialist for further tests and treatment.
Dehydration, which results from reduced levels of water and salt in the body, can cause low blood pressure. This can often be managed by increasing fluid and salt intake.
Wearing compression stockings can help improve blood circulation and pressure.

High blood pressure (hypertension)

Hypertension, the medical term for high blood pressure, occurs when the force exerted by the blood against the artery walls is consistently too high, requiring the heart to work harder to pump blood to other parts of the body.

Prediabetes can be identified by three testing methods:

Complications

Left untreated, hypertension may lead to serious health problems such as stroke, heart attack, angina, peripheral artery disease, kidney disease or kidney failure, vision loss, and sexual dysfunction.

Treatment

If you have elevated blood pressure, your doctor may recommend modifying or adjusting your lifestyle:

Maintain a healthy weight.
Adhere to the DASH (Dietary Approaches to Stop Hypertension) dietary plan that emphasises the consumption of fruits, vegetables, whole grains, fish, poultry, nuts, legumes, and low-fat dairy.
Limit sodium intake to less than 6g of salt per day and get enough potassium.
Engage in at least 30 minutes of physical activity each day, and consider incorporating resistance training, such as lifting light weights.
Limit your alcohol intake, stop smoking, get adequate sleep, manage stress, stay hydrated, and monitor your blood pressure.

If your blood pressure consistently measures above 140/90mmHg (or 135/85mmHg at home) and your risk of other health issues is significant, medications will be recommended alongside lifestyle modifications to reduce your blood pressure.

If your blood pressure consistently exceeds 160/100mmHg, medication will also be offered along with lifestyle changes. Medications include angiotensin-converting enzyme (ACE) inhibitors, angiotensin-2 receptor blockers (ARBs), calcium channel blockers, diuretics, and beta-blockers.

Adhere to your medication schedule as prescribed, as missing doses can compromise its effectiveness. Long-term use of blood pressure medication may be necessary. However, your doctor may consider reducing or discontinuing treatment if your blood pressure remains well-managed over several years.

Monitoring blood pressure at home

Blood pressure monitoring kits for personal use are readily available. If you have hypertension, check your blood pressure regularly as your doctor recommends. Additionally, if you have risk factors for hypertension or cardiovascular disease, such as obesity, diabetes, or a family history of high blood pressure, monitoring your blood pressure is also advised.

To maintain consistency, measure your blood pressure at the same times each day, such as morning and evening. Take your readings daily, starting two weeks after any treatment changes and continuing through the week before your next appointment.

For accurate results with your home blood pressure monitor, follow these steps:

Step 1: Avoid smoking, consuming caffeine, or exercising for at least 30 minutes before taking a measurement. Ensure you empty your bladder and rest quietly for at least five minutes beforehand.

Step 2: Sit upright with your back supported and feet flat on the floor, keeping your legs uncrossed. Place your arm on a flat surface, like a table, so that the cuff is at heart level. Make sure the bottom of the cuff aligns with the bend of your elbow.

Step 3: Follow the instructions provided with your blood pressure monitor for correct placement and use. If needed, ask your doctor to show you how to use the monitor properly.

Step 4: To ensure accuracy, take two readings one minute apart and record the results.

Step 5: Always place the cuff directly on your bare skin, not over clothing, for precise measurements.

Make an appointment at Gleneagles Hospitals

Take charge of your blood pressure starting now. Monitor it regularly, adopt a healthy lifestyle, and collaborate closely with your doctor to manage hypertension effectively. Your proactive approach can enhance your health and lower the risk of complications.

A dedicated and expert team of Cardiologists at Gleneagles Hospital is available for consultation to provide the best care and assistance. Get in touch with us to book an appointment today if you have any concerns or questions regarding high or low blood pressure.