Understanding Hypertension (High Blood Pressure)
What is hypertension?
When you have hypertension, your blood pressure is chronically too high.
This means that the force of the pressure inside your blood vessels is elevated and the heart must work harder to pump blood through the body. Over time, this can lead to a weakening of the heart and damage to the blood vessels in other organ systems.
Hypertension is a chronic condition that requires long-term management to avoid serious health complications like heart attack and stroke.
How do you know you have hypertension?
Hypertension is known as the “silent disease” as there may be no signs or symptoms that your blood pressure is elevated.
Therefore, it is important that you have regular check-ups with your doctor, especially if you have any of the following risk factors:
- Over 40 years of age (blood vessels stiffen with age)
- Overweight or obesity
- Sedentary lifestyle/physical inactivity
- Unhealthy, high-salt and high-fat diet
- Family history of hypertension
- Over-consumption of alcohol
- Diabetes or kidney disease
Headaches, blurry vision or coloured dots floating in your vision (medically known as “floaters”), shortness of breath, swollen ankles, nausea and vomiting, confusion and nosebleeds are all signs that your blood pressure may be dangerously high.
You need to contact a healthcare professional immediately if you experience these symptoms.
What do blood pressure measurements mean?
According to the Southern African Hypertension Society, South Africa has a high rate of heart attack and stroke because, like other diseases of lifestyle, hypertension remains untreated or poorly managed in 90 % of those affected. This may be due to insufficient regular testing, ineffective diagnosis and failure to initiate treatment on diagnosis.
About 50 % of those with hypertension are unaware of their condition.
It is therefore very important that your healthcare provider checks your blood pressure regularly.
Doctors and nurses take blood pressure readings as part of routine check-ups. It is recommended that your blood pressure is tested twice a year if you are 18 years or older. However, if you are aged over 40 years, or have any risk factors for high blood pressure, your doctor may want to check your blood pressure more often.
Blood pressure is usually measured with an inflatable cuff and stethoscope or digital monitor, and generally once in both arms to determine if there is a difference.
You’ve probably heard your doctor say something like “120 over 80”? This is because blood pressure is given as two numbers, measured in millimetres of mercury. The first number is your systolic blood pressure, or the pressure in your arteries when the heart contracts and the corresponding pressure inside your arteries rises. The second number is the diastolic blood pressure, or the pressure in your vessels when the heart relaxes between heartbeats.
The numbers to know:
- Your blood pressure is normal and healthy if it is at or below 120/80 (meaning less than 120 mmHg of systolic blood pressure and less than 80 mmHg of diastolic blood pressure).
- If your blood pressure is less than 140/90 but above 120/80, then you are at a risk of becoming hypertensive. Your doctor may say you are “prehypertensive”. You need to take immediate steps to improve your lifestyle and you need to meet with a healthcare provider regularly to reassess your blood pressure.
- If your blood pressure is above 140/90, a healthcare provider will do repeat measurements to see if you are hypertensive. You will need to change parts of your lifestyle (like your diet) and you may also need to receive treatment to reduce your blood pressure.
Alternatively, to confirm if you have hypertension, your doctor may suggest 24-hour ambulatory blood pressure monitoring (ABPM). ABPM is the process of having your blood pressure measured many times continuously over a 24-hour period. This is usually done at a healthcare facility, where measurements are taken every 30 minutes during the day and every hour at night, with the average measurement calculated for the complete 24-hour period.
AMBP is a very good way for your doctor to pick up abnormal fluctuations in blood pressure due to “white-coat syndrome” (blood pressure rising due to nervousness or anxiety about being tested by a doctor or at a healthcare facility, and which would not necessarily indicate actual hypertension) or due to masked-hypertension (fluctuations in blood pressure where levels are sometimes normal and other times not – this would be missed by a single reading by a doctor or nurse).
Sometimes, your doctor may also suggest 24-hour ambulatory blood pressure monitoring to determine how well your blood pressure medication is working.
What is the difference between primary and secondary hypertension?
Most cases of high blood pressure are classified as primary hypertension, also known as essential hypertension, which is high blood pressure without a known secondary cause. Primary hypertension is related to lifestyle factors, genetics and salt metabolism in the body.
On the other hand, secondary hypertension is high blood pressure due to an identified underlying condition, like kidney disease or endocrine/hormone conditions such as hyperthyroidism or Cushing’s syndrome.
What causes hypertension?
According to the Southern African Hypertension Society, approximately 30 % of all adult South Africans have high blood pressure. There are also 1.5 billion people affected by hypertension worldwide and this number is expected to grow between 15 to 25 % by 2025.
The major risk factors for hypertension include a family history of hypertension, being overweight, eating a diet high in salt, being physically inactive, smoking, frequent and excessive alcohol consumption, high levels of chronic stress and having certain chronic, underlying medical conditions.
Additionally, blood pressure increases with age (starting roughly at age 45 years, but the risk of hypertension increases most significantly after 65 years).
Specific detail on how these factors contribute to high blood pressure are as follows:
- Age: Blood vessels stiffen with age. Blood pressure begins increasing at about age 45. The risk is different dependent on your sex, as more men seem to be hypertensive between 45-65 years old, while more women are hypertensive after 65 years.
- Genetic influences: The genetics of hypertension are complex, with over 100 genes identified as responsible for controlling blood pressure. The most important genes are those which control sodium (salt) metabolism.
Sodium levels regulate fluid balance in the body. Some people have better sodium metabolism based on their genetics, and this may explain why hypertension is more common in certain families.
Hypertension is also more common among people of African ethnicity, such that people of this demographic may experience hypertension at a younger age and more severely than other demographic groups.
- A high salt diet: Eating too much salt (sodium chloride) causes your kidneys to retain more fluid and pushes blood pressure up.
- Overweight or obesity: The more you weigh, the more blood the heart must pump over a greater distance. As the amount of blood circulating increases, so does the pressure in blood vessels.
- Lack of physical activity: Generally, the less physically active you are, the higher your heart rate (number of times the heart beats per minute). This means your heart must work harder with each beat, exerting more force on blood vessels.
- Smoking: The chemicals in tobacco smoke (including nicotine) cause blood vessels to constrict almost immediately, damaging them and causing them to remain narrowed over time.
- Alcohol: Long-term excessive alcohol consumption damages the heart and kidneys and causes blood vessels to constrict.
- Stress: When you experience stress, your body releases the stress hormones, adrenalin and cortisol, for a “fight or flight response”. This causes your heart rate to go up and blood vessels to constrict.
If you experience chronic stress or anxiety, then these changes could adversely affect your heart and blood vessels, causing hypertension.
- Chronic Diseases: If you have certain chronic conditions, like diabetes and kidney disease, you are at greater risk of being hypertensive.
*Blood pressure generally increases when a woman is pregnant. However, if blood pressure becomes too high during pregnancy, then a life-threatening condition called pre-eclampsia may develop.
Therefore, if you are pregnant, ensure that your blood pressure is measured regularly by your healthcare provider.
Living and managing
You can reduce your risk of developing hypertension, or if you have been diagnosed with hypertension already, you can manage your blood pressure levels, through healthy lifestyle behaviours. However, some people may also have to take certain medications to ensure their blood pressure stays within healthy levels.
By working closely with your doctor, you can manage your blood pressure by focusing on these specific key areas:
- Eat a healthy diet low in salt
This is crucial to correctly managing your blood pressure. A high-salt diet is directly linked with higher blood pressure levels and the risk of developing hypertension, so try to limit your salt intake. See tips on how to add flavour to your food without using salt at Cooking from the Heart.
Take-away foods and premade meals, sauces, soups and gravies, as well as snacks like chips, tend to be high in salt and should be avoided as much as possible. You can view the salt content of common food types and brands here. Download the Cooking from the Heart Low-salt Booklet so that you will never be tricked by complicated, and often misleading, food labels. The booklet is essential for healthier cooking, shopping and snacking!
Additionally, it has also been proven that eating plenty of fruits, vegetables, whole grains, legumes (like lentils and beans) and low-fat dairy helps reduce the risk of developing hypertension. Eating lean meats like poultry and fish is also better for heart health than eating red or fatty meats.
Try to keep as active as possible. You don’t have to join a gym do this; instead, just take regular walks, ride a bike or dance along to the music on your radio. Your goal should be 30 minutes of moderate activity (makes you sweat and your heart beat a little faster) most days of the week.
An active lifestyle helps you to manage your blood pressure levels, with regular moderate to vigorous cardiac exercise (running and swimming) over several months proven to reduce blood pressure levels by up to 5 mmHg or more.
Regular physical activity also reduces the risk of heart disease and stroke and helps alleviate stress.
- Try to achieve and maintain a healthy weight
This is one of the most effective ways to reduce blood pressure. Losing 10 kg can reduce blood pressure by up to 5-20 mmHg. However, blood pressure starts decreasing significantly with smaller losses (2-5 kg), with greater reductions seen with the more weight you lose.
- Take your medication as prescribed
To bring down your blood pressure, your doctor may have also recommended you take medications in conjunction with changing certain lifestyle habits.
- Know your numbers – measure your blood pressure
Blood pressure can still be high even when you are taking medication, and levels can increase gradually over time. Therefore, it is important that your doctor knows your blood pressure levels so that they can adjust your medication as necessary.
Have your blood pressure measured by a healthcare provider habitually or preferably take regular measurements yourself at home if you have the correct equipment, as this can significantly improve blood pressure management and control.
There are many different blood pressure monitors that you can be prescribed by your doctor, or that you can buy at pharmacies. Having your own blood pressure monitor will enable you to effectively measure your blood pressure at home. Digital monitors are easy to use and usually consist of two parts: an inflatable cuff to wrap around your upper arm as indicated on the device (this will inflate and deflate), and a screen or gauge to read out measurements.
Tips on how to measure blood pressure accurately yourself at home are given here:
- Make sure the cuff fits your arm properly and does not cause any severe pain (besides the slight discomfort expected on inflation). Only take measurements with the cuff directly over your skin, not over clothing which can cause inaccurate readings.
- When you first buy the device, ask your doctor to test its accuracy and advise you how to use it properly.
Use the devise as the instructions show – you might want to ask your doctor to demonstrate how to use the device.
Blood pressure monitors also need to be calibrated. Take your home blood pressure monitor to your doctor’s office or healthcare practitioner to measure its accuracy against a mercury sphygmomanometer or other comparable device (this should be redone at least once every two years).
- Measure your blood pressure twice a day, the first in the morning before eating or taking your medications, and the second at night or in the evening. Your doctor may recommend when you should take measurements, and you should then stick to these times each day.
Each time, take three measurements to ensure that your results are accurate. Wait at least three minutes between each measurement and record the readings on a paper or digital log that you can show your doctor.
- But DO NOT take your blood pressure straight after waking up (this is a period when blood pressure naturally increases). Instead spend 20 to 30 minutes getting dressed, brushing your teeth or reading the newspaper before measuring your blood pressure. However, do not eat breakfast or take your medicines before you do the measurements.
- Avoid drinking coffee (or any caffeine), smoking or eating for 30 minutes before taking readings. These all increase blood pressure. Also try to empty your bladder before measurements, as a full bladder also increases blood pressure.
- Try to sit quietly and calmly before and while you are measuring your blood pressure.
- Manage stress
When you’re stressed, your heart rate and blood pressure go up. You also may not manage your blood pressure well and forget to exercise, eat right or take your medicines when you are anxious.
Find ways to relieve stress such as practising meditation, mindfulness or yoga.
- Stop smoking
Talk to your doctor about ways to quit smoking, as tobacco smoke increases blood pressure and your risk of heart disease and stroke.
- Limit your alcohol consumption
As excess alcohol consumption damages the heart and blood vessels, you will need to limit your alcohol consumption to effectively manage your blood pressure levels.
Talk to your healthcare provider about how much alcohol you are allowed to consume if you have hypertension.
Generally, to stay healthy, it is recommended that women not exceed one glass of alcohol per day, while men should have no more than two glasses per day.
What treatment is available for hypertension?
Types of blood pressure medications include:
- Angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) or calcium channel blockers that help to relax constricted blood vessels to relieve the pressure inside them.
- Diuretics that help to eliminate salt and thereby excess fluid from your body.
- Beta-blockers that reduce your heart rate and reduce the amount of blood the heart pushes into vessels on each contraction.
Your doctor will prescribe you the medication best suited for your needs or will prescribe a combination of medications to limit dosage amounts and reduce the chance of side-effects
It is very important that you take you blood pressure medication everyday as prescribed by your doctor. If you stop taking your medication, your blood pressure levels will not be managed correctly, and you will be at greater risk of heart attack or stroke.
Use a reminder system, like a daily tablet dispenser or tablet card or chart, to ensure that you remember to take your medications when needed. Even a note on the fridge or putting your tablets next to the dinner plates can help remind you when to take your medication – use whatever system works best for you.
If you experience side-effects from your blood pressure medication (dizziness, tiredness, cold extremities or impotence), do not stop taking your medication but report the side effects to your doctor or other healthcare provider as soon as possible, so that they can advise you on how to safely alter the dosage you take or change the type of medication you are on.
What are the complications associated with hypertension?
If you do not manage your blood pressure to within healthy levels, you risk damaging your blood vessels in other organ systems. Such damage will leave you with increased risk of:
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