In this post, we are going to attempt to answer some of the questions you might have about blood pressure.
In preparation for this post, we spent several weeks collecting questions people posted about blood pressure on popular sites such as Quora, Lowyat forum and Reddit and grouped them all in a logical manner so that you can find your answer more easily when browsing through the post.
Let’s dive right in:
- Blood pressure 101: Basics explained
- Measuring your blood pressure
- Low blood Pressure
- High Blood pressure
Blood pressure is a very common problem here in Malaysia. Many peopl actually have a lot of questions but don't know who to ask. We have summarised the answers to all the questions we covered in this post here.
Blood pressure 101: Basics explained
What is blood pressure?
Everytime when your heart beats, the heart muscle contracts and pushes the blood out from the heart to your body. This process happens 24/7 when you are alive – the blood from the heart carries fresh oxygen to all other parts of your body.
but the blood doesn’t just flow uninterrupted within the blood vessels. The wall of the blood vessels exerts a force that slows down or even halt the blood flow. The further the blood travels away from your heart, the slower the blood flows because of this force.
(Image credit: medicinenet.com)
And in order to make sure the blood can reach even the farthest organ, the heart needs to pump effectively, making sure that the initial pressure it exerts is forceful enough to overcome the resistance from the vessel’s wall.
and that’s BLOOD PRESSURE.
What is the normal range of blood pressure?
A blood pressure reading has a top number (systolic) and bottom number (diastolic). (Note: We will discuss more about the two numbers later on.)
Normal blood pressure is less than 120 over 80 (120/80). A systolic pressure of 130 to 139 mmHg OR diastolic pressure of 80-89 mmHg makes you a stage 1 hypertensive patient. You are a stage 2 hypertensive if you have systolic pressure of 140 or higher OR diastolic pressure of 90 or higher.
Doesn’t blood pressure go up naturally with age? I’m 64 this year, should I be worried if my blood pressure is higher than 120/80?
Blood pressure naturally becomes higher as you age due to loss of elasticity of the blood vessel. Ideally, you would want your blood pressure to be less than 120/80 but in reality, the average blood pressure of a healthy adult of 64 years old is about 134/87.
So, refer to this normal blood pressure chart by age to find out if you fall within the “okay” range. And if you are not, please consult your doctor to discuss if you should be using a medication.
What causes blood pressure to rise
Imagine you have a garden hose connected to a tap. Every time you turn on the tap, water flows into the hose.
and once the hose is fully filled with water, every time you turn on the tap, the pressure from the tap will force the water in the hose to squirt out.
Now imagine your heart being the water tap, hose being your blood vessels, and water being the blood in your body. Every time when your heart beats, the tap gets turned on for a brief second.
And blood pressure is equivalent to how far the water travels after being squirted out.
If the pressure is high, the water shoots out like a water jet, and if the pressure is low, the water simply flows out instead.
So now, under what circumstances will the water shoot more forcefully?
1.) Analogy: You use a bigger tap which sends more water into the hose
Explanation: When we are under stress, or during work outs, our heart pumps harder. As a result, each pump sends more blood into the blood vessels, and thereby increasing the pressure.
2.) Analogy: You squeeze the opening of the garden hose, making it narrower
Explanation: When your blood vessels become narrower, blood is forced to move faster and therefore exerts a stronger pressure.
3.) Analogy: You turn on and off the tap more frequently
Explanation: When the heart pumps faster, more blood gets sent into the blood vessels more often. This causes the pressure to build up.
So to recap, three conditions cause the blood pressure to rise: Your heart muscle squeezes more forcefully (a.k.a heart pumps harder), your blood vessels become narrower, your heart beats more frequently.
My pressure is normally 120/80, but this morning it suddenly shoots up to 145/86. Should I be worried?
It depends. There are many reasons why people experience sudden sharp rise in blood pressure. Caffeine, cold & flu medications, anxiety, lack of sleep, stress, nicotine in cigarette are some examples.
The best thing to do is to examine yourself and see if there is any sudden chest pain, blurred vision, nausea and vomitting, fatigue and confusion. If there is, go to the hospital immediately and get a more thorough check-up. Otherwise, just relax yourself for a few hours (get some sleep if possible) and redo the blood pressure test and see if it goes down. If the pressure spike remains for longer than a few days, you might need to speak to your doctor about getting treatment to help control your blood pressure.
How is blood pressure maintained in our body
Generally speaking, our body is quite smart. For blood pressure detection, we have a few baroreceptors in the body. Think of them as a pressure monitor system in our body, whenever the pressure gets too low or too high, the system will send signals to other parts of the body that regulates the blood pressure.
Upon receiving the signals from the baroreceptors, our body reacts in different ways, often simultaneously:
- Heart pumps harder (in case of low blood pressure) or weaker (when blood pressure is high), altering the force and volume of blood getting pumped into the body
- The blood vessels constrict (when pressure is low) or relax (when pressure is high).
- Heart pumps faster (when pressure is low) or slower (when pressure is high).
- Kidneys absorb (when pressure is low) or expel (when pressure is high) more water from the blood or to the urine. That changes the total volume of blood, higher volume means higher blood pressure and lower volume means lower pressure.
These 4 mechanisms are also how we can use blood pressure medications or supplements to reduce our blood pressure.
Measuring your blood pressure
How does blood pressure machine work
To explain the concept, we have drawn up some simple diagrams for illustration. So the following picture is how your blood normally flows through you arm.
When you apply the cuff to your arm, the machine pumps air into the cuff to inflate it. The cuff then tightens around your arm until the pressure is higher than your blood pressure. When that happens, no blood can flow through.
The machine then slowly deflates the cuff and the pressure in the cuff slowly gets lower and lower until it hits a point where the blood pressure is equal or slightly higher than the cuff pressure. This normally happens when your heart is pumping and when your blood pressure is at its highest. Blood can now force its way through the vessels, and the detectors in the cuff “listen” for this and the machine records this reading.
Next the machine continues to deflate the cuff until the blood can freely flow through the blood vessels, even when the blood pressure is at its lowest – when the heart muscle relaxes. The detectors in the cuff picks this up and record this second reading.
The two pressure readings recorded are your systolic blood pressure and your diastolic blood pressure reading.
Why are there two readings – what do they each mean?
Systolic blood pressure is your blood pressure reading when your heart muscle contracts and pumps out all the blood within it. Using our tap & hose analogy, that’s when you turn on the tap.
The volume of blood increases and the force created by the contraction of heart muscle forces the blood to flow more forcefully to your whole body.
This is when your blood pressure is at its highest.
Diastolic blood pressure on the other hand, is your blood pressure reading when your heart muscle relaxes and opens up the chambers within to contain the blood coming from other parts of your body.
At this point, the volume of blood in the blood vessels decreases and the blood pressure drops to its lowest point.
My blood pressure is 120/95. The upper number (systolic) is normal even though the lower number (diastolic) is high. Do I have high blood pressure then?
Yes. According to The American Heart Association, you are considered to be hypertensive if your systolic blood pressure is >120mmHg OR your diastolic blood pressure is > 80mmHg.
Which number is more important? Systolic or diastolic?
We typically pay more attention to the systolic blood pressure. High systolic blood pressure is a major risk factor for heart diseases, and factors such as lack of exercise, high cholesterol, and aging in general all affect the systolic blood pressure directly.
But that doesn’t mean that diastolic blood pressure is not as important.
In fact, according to the latest studies, the risk of death from heart disease and stroke doubles with every 20 mm Hg systolic or 10 mm Hg diastolic increase.
When should you measure your blood pressure – what is the best time to measure blood pressure?
If you have a blood pressure machine at home and you want to get the most out of it, the best practice is to measure your blood pressure several times a day.
For people with a blood pressure machine at home, try to make it a habit to measure at least twice a day, once shortly after waking up and once before going to bed. Don’t do it immediately after waking up, sit for at least 5-10 minutes before taking your first blood pressure reading.
If you can only do it once a day, i.e getting checked at local pharmacy, do it in the morning before breakfast. Most people like to drink coffee in the morning with breakfast and coffee is known to increase your blood pressure.
Make it a consistent habit to check daily around the same time.
I’m on blood pressure medications, does that affect when I should be taking my blood pressure reading?
If you are on blood pressure medication, the best time to check is in the morning right before you are supposed to take your next dose of medication.
At this point, the amount of medication left in your body is at its minimal and you can get a better understanding of your body without the effect of medication. If your medication has been working well, your blood pressure should still be within the normal range.
Correct way of measuring blood pressure
- Sit quietly for at least five minutes before doing the test
- Sit in a chair with your feet on the floor.
- Place your arm on a support so that your elbow is above heart level
- Place the cuff on your upper part of your tested arm (above elbow). The cuff should cover at least 80% of your upper arm.
- If possible, do it over bare skin and not over your shirt. Studies have shown that clothing can impact the blood pressure reading from 10 – 50 mmHg
- Start the machine.
- Do not talk during the measurement.
- Have your blood pressure measured twice, with a brief break in between. If the readings are different by 5 points or more, have it done a third time.
Does it matter which arm I use for blood pressure checking?
Yes. Because your left arm is closer to the heart than your right arm.
So don’t be surprised if you see a difference in reading when doing it on both arms. Normally the reading is slightly higher when you are doing it on the left arm, but the difference shouldn’t be more than 10mmHg.
Newer studies actually encourage people to regularly test it on both arms. If you notice a big difference (>10mmHg), you are advised to speak to your doctor about it.
note: A big arm-to-arm difference could occur when a muscle or something else compresses an artery supplying the arm, or by a structural problem that prevents smooth blood flow through an artery. A high arm-to-arm difference greatly increases your chance of getting heart disease/stroke.
Low blood Pressure
Definition of low blood pressure
The ideal blood pressure is 120/80mmHg, and you are considered to have hypotension or low blood pressure if your blood pressure is constantly lower than 90/60.
What causes low blood pressure
As mentioned above, our body is smart in terms of blood pressure regulation. If the blood pressure gets too low, our body will detect and correct it via one of these few ways:
- Heart pumps harder, sending more blood into the blood vessels with each pump.
- Blood vessels constrict, forcing the blood to flow faster
- Heart pumps faster
- Water retention happens and water gets reabsorbed into the blood instead of going into the urine.
So, hypotension (low blood pressure) happens when these methods fail to restore the blood pressure.
Some common causes include: External causes
- Diuretics – a type of substances that makes you urinate more often.
- medications that slows down heart rate
- Medications that relax your blood vessels
- heat stroke
- Loss of blood
- Weaker heart – weaker heart means less forceful pump.
- Low blood volume
- Slower heart rate
Symptoms of low blood pressure
Generally speaking, low blood pressure is pretty harmless compared to high blood pressure.
When the blood pressure is low, not enough blood with fresh oxygen supply reaches all parts of the body. As a result, cells do not receive enough oxygen and nutrients, and waste products are not adequately removed.
Normally when your blood pressure is low, the first organ affected is usually your brain. Brain is located at the top of your body, and blood must fight against gravity to reach there. So if pressure is low, less blood and by extension, less fresh oxygen reaches the brain.
The body then reacts by feeling dizzy or light-headed, or even fainting. Fainting is a reflex to bring your brain to the level of the heart so that blood can flow to the brain without having to fight gravity.
So, the symptoms of low blood pressure are:
- blurring of vision
- weakness （due to lack of oxygen)
- Cold, clammy skin – blood vessels tighten up to try and increase the blood pressure, so less blood flows to the surface of skin.
- pale skin
What to do when you have low blood pressure
If you suddenly experience a drop in blood pressure and feel dizzy/light headed, the first thing to do is to sit down or even lie down.
Drink lots of water when you feel better. Also, low blood pressure could be caused by low blood sugar. If that’s the case, make sure you get some sugary drinks that can quickly increase the blood sugar levels in your blood.
Make sure to consult your doctor if this sudden drop of blood pressure occurs frequently. Sometimes it could be caused by some other underlying medical conditions.
Are there medications for increase blood pressure?
Yes. Generally speaking, low blood pressure that doesn’t cause symptoms requires no treatment.
You can try one of these methods to increase your blood pressure:
- Use more salt
- Drink more water
- Wear compression stockings
Medication wise, when treating low blood pressure, doctors will first assess the patient’s situation and remove any underlying cause such as certain blood pressure or heart medications.
If no apparent cause is found, doctors may prescribe medications that can increase your blood volume or restrict the ability of your blood vessels to expand.
Can I still donate blood if my blood pressure is low?
Kudos to you for putting others wellbeing over your own.
Yes, according to the American Red Cross,you can still donate blood as long as you feel well and your blood pressure is at least 90/50.
You might feel weaker than normal people after donating blood so make sure you rehydrate and rest well after.
High Blood pressure
Definition high blood pressure
According to American Heart Association:
Blood pressure is considered normal if it is less than 120/80 mmHg.
If your systolic pressure is between 120-129 and diastolic less than 80mmHg, you are considered to have elevated blood pressure.
If you have a systolic pressure of 130-139, OR diastolic pressure of 80-89, you have Stage 1 Hypertension.
If your systolic pressure is 140 or higher OR diastolic pressure is 90 or higher, you have Stage 2 Hypertension.
If you have a systolic pressure of higher than 180 or diastolic pressure of higher than 120, you need to consult your doctor immediately. Blood pressure this high is what we refer to as hypertensive crisis. Blood pressure this high can cause damage to your internal organs and therefore need to be brought down immediately using medications.
How common is high blood pressure in Malaysia
According to the latest National Health & Morbidity Survey Malaysia (NHMS 2015), 35.3% of Malaysians actually suffers from high blood pressure.
In other words, one every third person has high blood pressure!!
What causes high blood pressure
Here are some common causes of high blood pressure:
- Increased blood volume (Blood pressure increases when blood volume increases):
- High salt intake: Excessive salt intake causes our kidneys to retain water – less urine produced and higher blood volume.
- Increased heart rate or stroke volume (Blood pressure increases when heart rate/stroke volume increases):
- Some medications such as antidepressants, cold & flu medications, thyroid hormone medications, asthma medications or heart medications can increase our heart rate when taken. Check with your doctor or pharmacist if you are unsure.
- Overweight or obese: Being overweight forces your heart to work harder to deliver sufficient nutrient and oxygen to all parts of your body. And when your heart pumps faster or harder, your blood pressure increases.
- Loss of elasticity of blood vessels. (When blood vessels become stiffer, blood pressure increases)
- Aging – loss of elasticity of blood vessels naturally occur as we age.
- Lack of exercise – Exercise opens up our blood vessels, and in turn allows blood to flow more freely. Doing exercise often “trains” our blood vessels to become more flexible and reduce the likelihood of plague formation around the blood vessels.
- High cholesterol – cholesterol in the blood can build up on the walls of your blood vessels (plague). And this plague becomes hard over time, making blood vessels narrower.
- High sugar in blood – High sugar in blood damages blood vessels, making them targets for hardening.
Can doing more exercise reduce my blood pressure? Can exercise replace medications?
Exercise can help improve your blood pressure in many ways.
- Strengthen your heart – regular exercise help to strengthen your heart and make it more efficient at pumping blood.
- Weight loss/fat loss – exercise helps you to lose that extra fat in your body. Losing fat means that it’s easier for your blood to send oxygen to other cells of your body. In other words, losing weight helps reduce the workload of your heart.
- Stress relief – When you are under stress, your brain releases stress hormones into your body which can make your heart pumps faster and harder. Exercise is proven to help get rid of stress.
But whether or not exercise can replace medications, the answer is no.
Not at least until we have studies to prove that exercise is at least as effective as medications.
Should I avoid doing certain exercise if I have high blood pressure?
Yes. Depending on your weight and blood pressure levels, you should really check with your doctor before doing any strenous exercise.
This is especially important if you have not exercised for a long time.
Start with just walking for 20 minutes and then slowly increase the intensity of your workout. A good way to gauge your exercise intensity is to check your heart rate.
Check out our other post on how to adjust your exercise intensity based on your heart rate.
Can I donate blood if I have high blood pressure?
Yes, regardless of whether or not you are taking blood pressure medications. As long as your systolic pressure is <180 mmHG and your diastolic pressure is <100mmHg at the time of donation.
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So there you have it, the most comprehensive blood pressure guide in Malaysia. We didn’t cover the medications and supplements for blood pressure in this post ( that would be another long topic on its own), but stay tuned for our next post in our blood pressure series: Supplements for blood pressure in Malaysia: What works, and what don’t.
Lastly, we recommend getting your blood pressure checked once a week. You should be able to get this service for free at any regular pharmacies and if you have any further questions, feel free to comment below or send us an email at firstname.lastname@example.org.