What is blood pressure?
Most of us have been to a doctor or nurse and had them wrap that thick band around the top part of our arm, it pumps up with air and then deflates, allowing the medical professional to get our blood pressure reading, but what exactly does this mean and how is it measured?
In wanting to find out about your blood pressure, it is often a good place to start in understanding what it allmeans and what the terms refers to. Basically, blood pressure measures the force with which your blood pushes against your arteries walls. Imagine water passing through a pipe – it is a similar movement, or rather concept, in which the blood passes through our arteries. Each time your heart beats, it pumps blood out to the arteries, and let’s not forget, the average person’s heart beats 60 to 70 times per minute at rest.
The following article discusses everything you need to know about your blood pressure, what it means for youas well as your health and lifestyle, possible precautions, treatments and more.
However, please keep in mind that this is merely a guideline and not intended to act as a diagnosis or treatment for any associated condition. Please consult with your healthcare professional for that.
What is a blood pressure reading and what do the two numbers mean?
Blood pressure numbers differ from person to person. It can sometimes be confusing as the two numbers may seem difficult to understand. For example, our blood pressure is written as 131/92, the explanation of the two numbers is as follows:
- The first number is your Systolic Blood Pressure Number. This refers to the pressure created when the heart beats, pumping blood through the arteries to get to the rest of your body. The blood being pumped creates a force on your blood vessels, this force is shown in the first number, your systolic number.
A normal systolic pressure is below 120. If your reading is at 140 or more, this is referred to as high blood pressure, however, a low blood pressure reading (lower than 80/60) is referred to as hypotension – it is important not to get confused between the two and to know what both can mean for you. There is more about this later. Please note that an individual is only diagnosed with hypertension (high blood pressure) when they have had three or more persistently elevated blood pressure readings that were taken on separate days, when the individual was at rest.
- The second number is referred to your Diastolic Blood Pressure Number, as opposed to the systolic reading which is known as the pressure as the heart pumps blood via the arteries, this refers to the pressure in the arteries when your heart is resting (or at rest) between the beats. This is the period where the heart can get oxygen when it fills with blood.
A good pressure is below 80, anything higher than 90 is known as a high blood pressure.
Healthy adults usually give a reading of 120/80 or lower, when it is above this it turns into prehypertension or hypertension. When it drops below this reading it turns into hypotension as mentioned above.
When looking at the number of the readings, this can get quite confusing, simply put, mm Hg means millimetres of mercury, this refers to the units used to measure your blood pressure.
What exactly happens when my doctor or nurse takes my blood pressure?
Taking your blood pressure is an easy and painless procedure, it is also a rather speedy process and one that is conducted by most healthcare professionals as part of routine examinations. Basically, your doctor or nurse measures your blood pressure with an inflatable cuff that is attached to a small gauge, the cuff wraps around your upper arm. Then, the doctor or nurse will use a stethoscope (an acoustic medical device used for listening to bodily sounds) to listen to your blood moving in your artery.
Then, your healthcare professional will inflate the cuff on your arm to raise it to a higher pressure than your systolic pressure, as it tightens around your arm it might be a bit uncomfortable, don’t worry, it doesn’t inflate for long and it certainly shouldn’t pop from the pressure. The cuff is made from a strong and durable fabric to ensure such accidents don’t happen.
Listening to the stethoscope, your doctor will then deflate the cuff and the first sound they hear will be your systolic blood pressure, making a whooshing sound, like water flowing through a hosepipe. When this sound stops, this point will mark your diastolic pressure. Basically, when the heart has a breather, gets oxygen and isn’t pumping blood through the arteries.
That is why your systolic number always comes before the diastolic in the reading.
There are a number of factors that influence your reading, but what it basically means is that the more blood that is pumped through your arteries, the higher the blood pressure. If your artery walls are stiff or narrow they may resist the blood flow and increase the blood pressure. When your artery walls are more flexible and open, your blood pressure is decreased and gives a lower reading.
When should I get my blood pressure checked?
- If your blood pressure is of a normal and healthy reading, being 120/80, then you need only get it checked bi-annually, or when your doctor recommends.
- When your blood pressure is bordering on a high reading, known as prehypertension, then it is a good idea to consult with your doctor, he/she may recommend getting it checked annually. But, it is always a good idea to speak to your doctor should your reading be between 120 to 130 systolic and 80 to 89 diastolic.
- If your blood pressure is low, also known as hypotension, this is generally when your reading is below 90/60, depending on your symptoms, you may need to consult with your doctor immediately about the frequency of future readings and lifestyle changes as well as possible medication for treatment.
- If your reading is 140/90 to more, you may need to start medication. Consult with your doctor should you have hypertension.
How is blood pressure produced?
The ventricle chamber of the heart, which is the left lower section, is responsible for receiving oxygenated blood from the lungs which then pumps throughout the body. The heart is, therefore, filling with blood between the heartbeats, which we discussed earlier. This is the diastole phase, giving you your diastolic reading. The systolic reading comes from the systole phase when the hearts pumps to push the blood through the arteries.
Your heartbeat is the contraction of the ventricle chamber.
How does my body keep to a normal and healthy blood pressure?
Most of our bodies are very clever in managing to normally maintain healthy blood pressure readings, telling the heart when to pump more or less blood in order to function at peak performance. The communication happens because of small nerve cells called baroreceptors, these lie within arteries close to the heart. They “talk” to the kidneys, arteries, veins and the heart to increase, decrease or maintain the blood pressure.
When your blood pressure becomes too high, the baroreceptors tell the veins to the expand and return less blood to the heart, lowering the blood flow and blood pressure. The veins can also become narrower and send more blood to the heart and in turn increase the blood pressure. The baroreceptors tell the arteries the same thing, to constrict when the pressure is too low to raise it and to relax when the pressure is too high in order to lower it.
Just a quick note, arteries and veins have two different jobs to do. Arteries are responsible for transporting oxygenated blood away from the heart to the body and veins carry the deoxygenated blood back from the body to the heart. An easy way to remember this is the ‘a’ for arteries stands for A for AWAY!
What does it mean if I have low blood pressure (hypotension)?
Low blood pressure can often result in fainting and dizziness – this is caused by the low blood flow throughout the body. In some cases, it can be potentially life-threatening. However, low blood pressure is not usually unhealthy and can be easily lived with. The aforementioned symptoms are common when you move from lying down to standing positions. The condition is serious when the lack of blood flow to vital organs results in kidney failure, heart attacks and strokes.
If you are often susceptible to dizziness and feeling faint, it is best that you consult with your doctor or a healthcare professional in order to have your blood pressure checked and learn how to manage it if necessary.
Unlike high blood pressure, low blood pressure is defined by the signs of a low blood flow and not necessarily the reading.
Therefore, the symptoms can be characterised in the list below, if you experience any of these, stop what you are doing, try drink some water and sit down. If you have frequent symptoms, when they become chronic, you should consult with your doctor.
- Feeling dizzy and unsteady
- Blurred vision
- Confusion about your surroundings or actions
- Feeling weak
- Feeling sick in wanting to vomit
Possible Causes and Risks
If your blood pressure reading is low, you doctor will often check if it is a result of any of the following:
- Stress levels – in general, the more relaxed you are, the lower your blood pressure will be. However, panic and anxiety attacks may lead to hyperventilation wherein your body feels like it is unable to get enough air, although the reality is that you’re getting too much by breathing in a rapid manner. Without enough carbon dioxide, the body has to work harder to operate correctly and so it will increase the dilation of blood vessels in order to get the blood to flow quicker and this can cause a drop-in blood pressure.
- How often you exercise – if you are healthy and exercising daily, your blood pressure will be low when you are resting.
- What time of day it is – your blood pressure rises during the day and decreases towards your bed time and when sleeping.
- What the temperature it is – if the weather is hot, your blood pressure may fall.
- If you have just eaten a meal – when you have just eaten, blood is sent to your gut to help in processing the food, the blood pressure in the rest of your body drops.
- As you get older, your blood pressure normally rises. But it is also possible that it may drop as the body is unable to regulate its circulatory system as well as it may have when you were younger.
- Some research has indicated that blood pressure may be genetic – meaning that if your parents have a low blood pressure, you could also be at risk.
Some medication may cause your blood pressure to drop:
- Diuretics (water tablets)
- Beta-blockers – medicine that is used for heart problems.
- Alpha-blockers – these are medicines used to lower your blood pressure when suffering from hypertension, as well as to treat men who suffer from prostate problems.
- Some antidepressants – check with your doctor to make sure your medication is not affecting your blood pressure.
If you are considered to be at risk of hypotension, it is important that your doctor ensures that your medicine does not worsen the situation.
Possible health conditions linked to low blood pressure
- Heart conditions such as a heart attack may cause the heart to pump less blood.
- Anaemia can often link to low blood pressure, where there are fewer red blood cells or a lessened amount of haemoglobin (protein molecules in the red blood cells that transport oxygen from the lungs to the body and bring carbon dioxide back to the lungs) than normal.
- Neurological disorders affecting your nerves.
- Hormone problems such as diabetes or other conditions like hypothyroidism (having an under active thyroid).
Serious injury or shock
- Losing a lot of blood through injury.
- Shock to the body such as anaphylactic shock, caused by an allergic reaction, causes your body to produce a large amount of histamine to combat the reaction. This causes your blood vessels to widen and therefore a drop in your blood pressure is the result.
How should I treat low blood pressure?
If you suffer from chronic low blood pressure symptoms, as listed above, it is best to seek advice and prognosis from your doctor.
However, there is some general advice when it comes to dealing with low blood pressure:
- Stand up slowly, especially first thing in the morning, allowing your body to adjust to the movement and get the blood flowing. It may also help to stretch in bed before you get up.
- Try not to stand for long periods of time this can help to prevent miscommunication between the heart and brain, which is known as neurally mediated hypotension, this is also known as the fainting reflex.
- Sometimes compression stockings help provide extra pressure for your feet, legs and stomach, which helps to improve circulation.
- Avoid caffeine and alcohol which could make you dehydrated.
- Eat smaller meals more frequently, this helps to prevent postprandial hypotension, this refers to the decrease in blood pressure that happens after a meal as your body sends more blood to your gut to process the food.
- Increase your fluid intake.
- Medication is often not prescribed for low blood pressure. If it is necessary, however, it will be used to narrow your arteries or increase your heart rate. The goal of treatment is to correct the cause of the low blood pressure. Medication cannot typically be prescribed to increase the volume of blood, however. this can be done through an IV drip or blood transfusion to replenish any blood that has been lost.
What does it mean if I have high blood pressure (hypertension)?
High blood pressure can increase your risk of heart disease and stroke, however many people with high blood pressure don’t have signs or symptoms and it can only be detected when a reading is conducted. A few people may exhibit symptoms such as shortness of breath, nosebleeds or possibly headaches, but these are not specific and usually only occur when the blood pressure has reached a life-threatening level. If you experience any of these symptoms, or a combination thereof, you should visit or call your doctor immediately if you know you suffer from high blood pressure.
Types of hypertension
There are two main types of hypertension. There is also prehypertension, which is basically a warning that you may be at risk for hypertension – view it as a warning sign.
Primary (essential) hypertension
This type of high blood pressure doesn’t have a known secondary cause and is believed to be linked to a poor diet, genetics and lack of physical activity. There are only treatments for this kind of hypertension, there is no cure.
Possible Causes and Risks
- Genetic factors
- Unhealthy diet
- Being overweight – this increases your vascular resistance in having more fatty tissue which increases the amount of work the heart has to do in order to pump blood to your body.
Your doctor may recommend that you lose weight and follow a strict exercise and eating regime. That being said, the following can be done to help to lower your blood pressure:
- Eat a healthy diet with a good amount of fibre and potassium, as well as drink plenty of water. It will also help to eat whole grains, fish and low-fat dairy as well as fruits and vegetables.
- Exercise for at least 30 minutes a day.
- Try and limit your salt intake to 1,500mg per day.
- Quit smoking.
- Limit your alcohol intake to one unit per day.
- Reduce your stress levels.
There is also medication available such as:
- Calcium channel blockers
- Renin inhibitors
These should be taken under the advisement of your doctor.
Your doctor may need to put you on a variety of medications in order to find the right mix that works for you to lower your blood pressure. You will also need to make conscious, healthy choices to improve your lifestyle as this could result in you not even needing medication in future.
You have a good chance of naturally combatting your blood pressure condition just through diet and lifestyle. However, this is not to say that you should not consult with your doctor, it is always best to get a professional opinion.
This type of blood pressure has a direct cause. It is generally caused by other medical conditions that normally affect your heart, kidneys or endocrine system. It can also occur during pregnancy.
Secondary hypertension is also something that does not have any specific symptoms, but if you have been diagnosed with high blood pressure by your doctor, it is important to know the following as these symptoms may mean you have secondary hypertension (please note that this is especially important for those who have been diagnosed with high blood pressure at a young age):
- Resistant hypertension is when you have high blood pressure that does not respond to any blood pressure medication.
- Have a blood pressure reading of over 180/120.
- Experience a sudden onset of high blood pressure after the age of 55 or before the age of 30.
- No family history of high blood pressure – secondary hypertension is not linked to genetics.
Possible Causes and Risks
The biggest risk for having secondary hypertension is having a medical condition that causes the high blood pressure.
There are several things that can cause secondary hypertension, these can include:
- Diabetes can damage the filtering system of your kidneys.
- Cushing syndrome is a condition where the medication may cause secondary hypertension, have a look at our article on Cushing syndrome.
- Polycystic kidney disease is an inherited condition where cysts in your kidneys stop your kidneys from working properly and can raise your blood pressure.
- Glomerular disease is where your kidneys filter waste and sodium by the use of tiny sized filters called glomeruli, if these do not work properly and become swollen, it might raise your blood pressure.
- Renovascular hypertension is caused by the narrowing of one or both of your arteries leading down to your kidneys.
- Aldosteronism is a condition where a tumour in the adrenal gland as well as an increased growth of the cells in the adrenal gland cause the glands to release a large amount of the hormone called aldosterone. This results in your kidneys retaining salt and water, and they will therefore lose a lot of potassium, spiking your blood pressure.
- Thyroid problems occur when the thyroid gland is overactive and this results in the thyroid producing too much of its hormones, which in turn, can cause the heart to beat faster than normal and ultimately raise the blood pressure.
- Coarctation of the aorta is a defect you are born with where the body’s main artery, your aorta, is narrowed and forces the heart to pump at a higher pressure.
- Hyperparathyroidism is a condition where the parathyroid glands which regulate your levels of calcium, if the glands secrete too much of the parathyroid hormone, your calcium levels will rise and this will trigger your blood pressure to rise. The exact mechanism of how it causes high blood pressure is still being debated, one thought is that it is through kidney damage as the kidneys play a vital role in controlling blood pressure.
- Sleep Apnea is often described as severe snoring, where your breathing will stop and start during your sleep, this causes you to lack in oxygen as you are not getting enough. This may result in damage to the lining of the blood vessel walls, stopping them from being effective in regulating your blood pressure.
- Obesity is a large contributing factor to high blood pressure. The heavier you are, the more blood you have circulating in your body, putting more pressure on your artery walls which will increase your blood pressure.
- Pregnancy may also cause high blood pressure.
There are many things that may cause your secondary hypertension, it is always best to consult with your doctor in order to treat any symptoms you may be experiencing. Medications and supplements such as painkillers, birth control pills as well as anti-depressants may also cause secondary hypertension.
The most common cause of secondary hypertension is kidney disease, have a look at our article on this as well as the relevant articles to the above-mentioned diseases.
- Arterial damage which can lead to a heart attack or stroke.
- Increased blood pressure can cause the blood vessels to lose their strength, causing a bulge which could lead to an aneurysm.
- Having trouble with your memory from the high blood pressure affecting your ability to think.
- Metabolic syndrome is basically a condition where your body has a collection of metabolic disorders – disorders directly associated with your metabolism.
- Weak and narrow blood vessels in your kidneys which prevents them from working properly.
- Torn, narrowed, thickened or damaged blood vessels in your eyes which results in vision loss.
Other types of hypertension
There are various types of hypertension, read more about them in our articles on malignant and renal hypertension.
How can I keep my blood pressure at a healthy reading?
It is important to maintain a healthy lifestyle and diet. There are several factors as stated above that can result in your blood pressure being too low. The point of the matter is that you should always get it checked out by your health care professional to ascertain what you are dealing with.