Introduction

In order to survive, the body needs oxygen and nutrients. The heart supplies this by constantly circulating blood round the body through the arteries. Arteries carry blood from the heart to other parts of the body. As blood travels through these arteries it pushes against the walls of the arteries, the force by which it does so is known as blood pressure (Suzanne, 2019). Blood pressure is determined both by the amount of blood the heart pumps and the amount of resistance to blood flow in the arteries (American Heart Association, 2020).

Blood Pressure Readings

 A blood pressure reading is given in millimetres of mercury (mm Hg). It has two numbers.

Systolic pressure: Measures the pressure in the arteries as the heart beats and is the top number on a blood pressure reading.

Diastolic pressure: This represents the blood pressure when the heart is resting between beats. It is the lower number on the blood pressure reading (American Heart Association, 2017)

Blood Pressure Categories

1, Normal blood pressure: A blood pressure value of less than 120/80mmHg is considered normal and a healthy, active lifestyle is required to maintain this value (Flack and Adekola, 2020).

2, Elevated blood pressure: This is a value of 120–129 systolic and less than 80 mm Hg diastolic. Diet and lifestyle modifications are recommended for individuals in this category (Flack and Adekola, 2020).

3, Stage 1 or Moderate Hypertension: This is a value of 130-139 systolic and 80-90 diastolic. It is recommended the patient employ healthy lifestyle changes  combined with a BP-lowering medication (American Heart Association, 2017).

4, Stage 2 or Severe Hypertension: This has a systolic pressure value of 140 mm Hg or higher and a diastolic pressure of 90 mm Hg or higher. A combination of healthy lifestyle changes and blood pressure-lowering medication is recommended along with monthly follow-ups until blood pressure is controlled (American Heart Association, 2017).

5, Hypertensive crisis: A blood pressure measurement higher than 180/120 mm Hg is an emergency situation that requires urgent medical care. If this result is obtained when blood pressure readings are taken at home, wait five minutes and retest. If it’s still this high, see a doctor immediately. If chest pain, vision problems, numbness or weakness, breathing difficulty, or any other signs and symptoms of a stroke or heart attack are also experienced, call the local emergency medical number (American Heart Association, 2020)

Systolic (mm Hg)Diastolic (mm Hg)
NormalBelow 120Below 80
Elevated (hypertension)120–129Below 80
Stage 1 hypertension130–13980–90
Stage 2 hypertension140 or above90 or above
Hypertensive crisisOver 180Over 120
Table 1: Blood Pressure Range (Whelton et al, 2017).

High blood pressure or hypertension

Figure 1: High Blood Pressure (iStock, 2019)

High blood pressure/hypertension (HBP) is a common condition in which the long-term force of the blood against the artery walls is high enough that it may eventually cause health problems, such as heart disease. The more blood a person’s heart pumps and the narrower their arteries, the higher the blood pressure (National Heart, Lung, and Blood Institute, 2020).

Economic Impact and Burden of High Blood Pressure

One-quarter of the world’s adult population has hypertension, and this is likely to increase to 29% by 2025. Currently about 1.13 billion people have hypertension (WHO, 2021). Modeled projections indicate an increase to 1.15 billion hypertensive patients by 2025 in developing countries. In the Eastern Europe and Central Asia region, high blood pressure consumed 25% of all health expenditures (Gaziano, 2009). Over a 10-year period, elevated blood pressure may cost nearly $1,000 billion globally in health spending, if current blood pressure level persists. Indirect costs could be as high as $3 600 billion annually (Gaziano, 2009). This total includes the cost of healthcare services, medications to treat high blood pressure, and loss of productivity from premature death. 

Relevant Statistics on HBP

Figure 2 : Hypertension prevalence by WHO region (WHO, 2020)

Hypertension is a major public health problem and a leading cause of death and disability in developing countries (Bharati, 2010). In 2002, blood pressure affected 1-in-4 adults and caused 7.1 million deaths globally (WHO, 2002). The absolute prevalence of hypertension in economically developed nations was 37.3% in 2005, compared with 22.9% in developing nations (Kearney, 2005). By the year 2010, more than one billion hypertensive adults were living in low and middle-income countries where mean BP control rates were 7.7% (Mills, 2016).

Currently, it affects 1-in-3 adults which indicates progress, although only about half of them have their condition under control. The prevalence of high blood pressure varies depending on country income groups and regions. As seen in fig 2, the WHO African Region and the WHO region of America have the highest and lowest prevalence of high blood pressure respectively (27% and 18%). In addition, the number of adults with high blood pressure have significantly increased to 1.13 billion people over the last four decades, particularly in low and middle income countries (WHO, 2021). The rise in cases is as a result of an increase in the prevalence of risk factors associated with the condition.Key statistics:

1, A greater percentage of men (50%) have high blood pressure than women (44%).

2, High blood pressure is more common in non-Hispanic black adults (56%) than in non-Hispanic white adults (48%), non-Hispanic Asian adults (46%), or Hispanic adults (39%).

3, The estimated pooled prevalence of hypertension is about 30.8% in African (Adeloye, 2014) and 30.0%-31.1% in Sub-Saharan Africa (Ataklte, 2015)

4, Among those recommended to take blood pressure medication, blood pressure control is higher among non-Hispanic white adults (32%) than in non-Hispanic black adults (25%), non-Hispanic Asian adults (19%), or Hispanic adults (25%) (Kochanek, 2019).

Figure 3: Raised Blood pressure prevalence globally by income and gender (Statista, 2016).

Figure 3 above, shows that low income level has the highest prevalence of high blood pressure in both male and females. This is because low income groups have been reported to engage in health-damaging lifestyles resulting in the development of poor dietary habits as well as influencing behaviors related to cigarette smoking and alcohol consumption (Mendez, 2003), exposing them to numerous risk factors leading to excessive burden of disease (Choi, 2006).

The blood pressure prevalence in male is higher than females across all income levels except low income levels. Several studies have shown that men younger than 65 consistently have higher levels of hypertension compared to women of the same age group. Observed gender differences in hypertension are due to both biological and behavioral factors (Sandberg, 2012). The biological factors include sex hormones, chromosomal differences, and other biological sex differences that are protective against hypertension in women (Sandberg, 2012), while behavioral risk factors for hypertension include high body mass index (BMI) (Brown, 2000) and, to a lesser degree, smoking (Halimi, 2002) and low physical activity (Haapanen, 1997).

Figure 4: Trends in the number of people with hypertension who reported a diagnosis, used treatment, and whose blood pressure was effectively controlled, globally and by region, 1990–2019. (NCD-RisC, 2021)

In high-income Western and Asia-Pacific regions as well as Central and Eastern Europe, the opposite effects of declining prevalence and population growth and ageing led to a small net increase in the number of people with hypertension (Fig. 4). The improvements in treatment and control from 1990 to 2019 shifted many of those with hypertension in these regions from being untreated to being treated and having their hypertension controlled. These improvements lowered the absolute number of those who were not treated or whose hypertension was not effectively controlled (NCD-RisC, 2021). It can also be deduced from the above figure, that undiagnosed high blood pressure cases were higher than reported diagnosed, treated and controlled hypertension across all regions globally. This is probably because most people with high blood pressure do not experience any symptoms, which is why people often call it the “silent killer.”

Types of High Blood Pressure.

There are mainly two types of high blood pressure: primary and secondary high blood pressure.

1, Primary, also known as essential high blood pressure: It is the most common type of high blood pressure making up about 95% of high blood pressure cases. For most people who get this kind of blood pressure, it develops over time as you get older (MedlinePlus, 2019). The underlying cause of this type of HBP can’t be found but has been linked to certain factors such as genetics, gender (affects men more than women), race (affects blacks more than whites), diet and lifestyle (Suzanne, 2019). 

2, Secondary high blood pressure: is caused by an underlying medical condition or the use of certain medications. It usually gets better after the condition has been treated or stopping the use of those medicines that are causing it (Suzanne, 2019). It is usually triggered by kidney disease, adrenal gland tumors, birth control pills and pregnancy amongst others (MedlinePlus, 2019).

Known causes of High Blood Pressure

High blood pressure can occur when certain changes happen in the body or if a person is born with specific genetic features that cause a health condition.

1, Obstructive sleep apnea

2, Kidney disease

3, Adrenal gland tumors

4, Thyroid problems

5, Certain defects you’re born with (congenital) in blood vessels

6, Certain medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs

7, Illegal drugs, such as cocaine and amphetamines (Whelton, 2017)

8, Obesity

9, Type 2 diabetes

10, Lupus

11, Scleroderma (NHS, 2019)

What can increase the risk of high blood pressure?

According to American Heart Association, the risk factors for high blood pressure include the following:

Age: The risk increases with age because the blood vessels become less flexible. Until age 64, men are more likely to get high blood pressure than women are. At 65 and older, women are more likely to get high blood pressure. 

Family history and genetic factors: People who have close family members with hypertension are more likely to develop it.

Ethnic background: African Americans have a higher risk of developing hypertension than other groups in the United States.

Obesity and being overweight: People with overweight or obesity are more likely to develop high blood pressure.

Physical inactivity: A sedentary lifestyle increases the risk. Physical activity is great for your heart and circulatory system in general, and blood pressure is no exception

Smoking: When people smoke, the blood vessels narrow, and blood pressure rises. Smoking also reduces the blood’s oxygen content, so the heart pumps faster to compensate. This, too, increases blood pressure.

Alcohol intake: Drinking a lot of alcohol increases the risk of blood pressure and its complications, such as heart disease.

Diet: A diet that is high in unsaturated fat and salt increases the risk of high blood pressure.

High cholesterol: Over 50% of people with high blood pressure have high cholesterol. Consuming unhealthful fats can contribute to a buildup of cholesterol in the arteries.

Mental stress: Stress can have a severe impact on blood pressure, especially when it is chronic. It can occur as a result of both socioeconomic and psychosocial factors.

Being overweight or obese: Carrying too much weight puts an extra strain on your heart and circulatory system that can cause serious health problems. It also increases your risk of cardiovascular disease, diabetes and high blood pressure. 

Stress: Persistent stress can lead to high blood pressure, and it may increase the risk of unhealthful choices, such as smoking.

Diabetes: High blood pressure often occurs alongside type 1 diabetes. Following a treatment plan to manage diabetes can reduce the risk.

Pregnancy: High blood pressure is more likely during pregnancy due to hormonal changes. Hypertension is also a symptom of preeclampsia, a potentially severe placental disorder.

Sleep apnea: People with sleep apnea momentarily stop breathing while they sleep. Experts say there are links with hypertension (American Heart Association, 2017)

Signs and Symptoms of High Blood Pressure

Most people with high blood pressure will not experience any symptoms, which is why people often call it the “silent killer.” However, once blood pressure reaches about 180/120 mm Hg, it becomes a hypertensive crisis, which is a medical emergency. At this stage, a person may have:

1, A headache

2, Nausea

3, Vomiting

4, Dizziness

5, Blurred or double vision

6, Nosebleeds

7, Heart palpitations

8, Breathlessness (Adam, 2019).

High Blood Pressure in Pregnant women: Preeclampsia

Figure 5: Overview of Preeclampsia (iStock, 2019)

During pregnancy, high blood pressure can be a sign of preeclampsia, a potentially dangerous condition that usually affects the woman and her unborn child. Other symptoms of preeclampsia are: headaches, abdominal pains, swelling due to edema and vision changes. When one or more of these symptoms arise, the condition should be treated immediately to prevent fatality of mother, unborn child or both (Adam, 2019). 

Table 2 below shows the specific symptoms of high blood pressure and underlying conditions/risk factors among different populations:

PopulationUnderlying Condition/Risk factorSymptoms of HBP
WomenPregnancy, menopause and the use of birth control pillsHeadaches, vision change, abdominal pain and edema
TeenagersObesity, type 2 diabetes, kidney disease, endocrine disease, vascular disease, neurological condition (Anyaebu, 2015)a headache, fatigue, blurred vision and nosebleeds (Anyaebu, 2015)
ChildrenObesity, diabetes, tumor, heart/kidney/thyroid problemsa headache, fatigue, blurred vision and nosebleeds
BabiesKidney or heart diseaseFailure to thrive, seizures, irritability, lethargy and respiratory distress
Table 2: Symptoms of high Blood Pressure in Women, Teenagers, Children and Babies (Adam, 2019)

Diagnosis of High Blood Pressure

Blood pressure can fluctuate according to the time of the day, when the person is feeling anxious or stressed and after eating. There are different devices for measuring blood pressure.

1, A doctor will often use a manual sphygmomanometer with a stethoscope. 

2, Digital devices are suitable for home use

Additional tests can be done to confirm diagnosis. Some of such tests are:

1, Electrocardiogram test (ECG)

2, Exercise stress test: Checks the heart health

3, Urine and blood tests: Checks for underlying problems like kidney damage

4, Holter monitoring

5, Echocardiogram: checks for thickening of heart wall, defective heart valves, blood clots, and excessive fluid around the heart (Bonow, 2019).

Ways to prevent and lower blood pressure

Figure 6: High Blood pressure: How to prevent it. (WHO, 2021)

Treatment often depends on how high the blood pressure is and the risk of cardiovascular disease or stroke. So doctors often recommend different treatments as blood pressure rises. These include:

1, Medication for really high blood pressure. Some of the medications recommended are: Angiotensin Converting Enzyme (ACE) inhibitors, Calcium channel blockers, Thiazide diuretics, Beta-blockers and Renin inhibitors (Mann, 2021)

2, Diet and eating healthy e.g. eating mostly plant based foods, lowering salt intake, eating healthful fats (plant sources of fat), using the DASH diet recommendation (Forman, 2020)

3, Lowering the intake of alcohol and caffeine (Chrysant, 2017).

4, Managing stress and Quitting smoking (American Heart Association, 2016)

5, Regular exercise and losing weight (Börjesson, 2016).

6, Getting the recommended hours of sleep

7, Natural remedies such as biofeedback and transcendental meditation; yoga, qi gong, tai chi and meditation; taking supplements such as garlic, flaxseed, green or black tea, probiotics, cocoa and roselle (Saper, 2021)

Figure 7: High Blood pressure diet (iStock, 2016)

Complications, Dangers and Side Effects of High Blood Pressure

Uncontrolled high blood pressure can lead to the following complications:

1, Heart attack or stroke (CDC, 2014)

2, Aneurysm. Increased blood pressure can cause your blood vessels to weaken and bulge, forming an aneurysm. (CDC, 2014).

3, Heart failure. To pump blood against the higher pressure in your vessels, the heart has to work harder. This causes the walls of the heart’s pumping chamber to thicken (left ventricular hypertrophy). Eventually, the thickened muscle may have a hard time pumping enough blood to meet your body’s needs, which can lead to heart failure (CDC, 2014).

4, Weakened and narrowed blood vessels in your kidneys.

5, Thickened, narrowed or torn blood vessels in the eyes. This can result in vision loss (CDC, 2014).

6, Metabolic syndrome. This syndrome is a group of disorders of your body’s metabolism, including increased waist size, high triglycerides, decreased high-density lipoprotein (HDL) cholesterol (the “good” cholesterol), high blood pressure and high insulin levels (Adam, 2019)

7, Trouble with memory or understanding. Uncontrolled high blood pressure may also affect your ability to think, remember and learn Adam, 2019).

8, Dementia. Narrowed or blocked arteries can limit blood flow to the brain, leading to a certain type of dementia (vascular dementia). A stroke that interrupts blood flow to the brain also can cause vascular dementia (Adam, 2019)

Figure 8: Hypertension: A silent killer – Symptoms and complications of high blood pressure (Servier, 2018)

Conclusion

Many people with high blood pressure do not have symptoms. For this reason, they must have regular screening, especially Africans, people with obesity or overweight, those with a previous history of high blood pressure, those with blood pressure that is at the high end of normal (from 130–139/ 85–89 mm Hg), people with certain health conditions, and adults aged 40 or older.

Reference

Adam Felman,  Alana Biggers. (2019). What to know about high blood pressure. https://www.medicalnewstoday.com/articles/159283 

Adeloye D, Basquill C. Estimating the prevalence and awareness rates of hypertension in Africa: a systematic analysis. PLoS One. 2014;9(8):e104300. Pmid:25090232.

American Heart Association. (2016).Managing stress to control high blood pressure. .https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure/managing-stress-to-control-high-blood-pressure.

American Heart Association. 2017. Know your risk factors. https://www.heart.org/en/health-topics/high-blood-pressure/why-high-blood-pressure-is-a-silent-killer/know-your-risk-factors-for-high-blood-pressure 

Anyaegbu, E., & Dharnidharka, V. (2015). Hypertension in the teenager. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947917/

Ataklte F, Erqou S, Kaptoge S, Taye B, Echouffo-Tcheugui JB, Kengne AP. Burden of undiagnosed hypertension in Sub-Saharan Africa: A systematic review and meta-analysis. Hypertension. 2015;65(2):291–8. Pmid:25385758 

Bethesda, MD: National Heart, Lung, and Blood Institute; 2003. National High Blood Pressure Education Program. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.

Blood pressure in children and adolescents. (2013).  https://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/blood-pressure-in-children-and-adolescents-hypertension-screening?ds=1&s=blood%20pressure%20screening

Bonow RO, et al., eds. Systemic hypertension: Mechanisms and diagnosis. In: Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Elsevier; 2019. https://www.clinicalkey.com. 

Börjesson M, et al. Physical activity and exercise lower blood pressure in individuals with hypertension: narrative review of 27 RCTs. British Journal of Sports Medicine. 2016; doi:10.1136/bjsports-2015-095786.

Brook RD, et al. Beyond medications and diet: Alternative approaches to lowering blood pressure: A scientific statement from the American Heart Association. Hypertension. 2013; doi:10.1161/HYP.0b013e318293645f.

Brown CD, Higgins M, Donato KA, Rohde FC, Garrison R, Obarzanek E, Ernst D, Horan M. Body mass index and the prevalence of hypertension and dyslipidemia. Obes Res. 2000;8(9):605–619.

Centers for Disease Control and Prevention, National Center for Health Statistics. About Multiple Cause of Death, 1999–2019. CDC WONDER Online Database website. Atlanta, GA: Centers for Disease Control and Prevention; 2019. 

Centers for Disease Control and Prevention. (2014). Effects of high blood pressure. (2014). https://www.cdc.gov/bloodpressure/effects.htm

Centers for Disease Control and Prevention. Hypertension Cascade: Hypertension Prevalence, Treatment and Control Estimates Among U.S. Adults Aged 18 Years and Older Applying the Criteria from the American College of Cardiology and American Heart Association’s 2017 Hypertension Guideline—NHANES 2015–2018external icon. Atlanta, GA: U.S. Department of Health and Human Services; 2021.

Choi KM, Park HS, Han JH, Lee JS, Lee J, Ryu OH, et al. Prevalence of prehypertension and hypertension in a Korean population: Korean National Health and Nutrition Survey 2001. J Hypertens 2006; 24:1515–1521. 

Chrysant, S. G. (2017). The impact of coffee consumption on blood pressure, cardiovascular disease and diabetes mellitus. https://www.tandfonline.com/doi/abs/10.1080/14779072.2017.1287563?journalCode=ierk20 

Forman JP, et al. (2020). Diet in the treatment and prevention of hypertension. https://www.uptodate.com/contents/search. Accessed Dec. 20, 2020.

Gaziano, Thomas A; Bitton, Asaf; Anand, Shuchi; Weinstein, Milton C. (2009). The global cost of nonoptimal blood pressure. Journal of Hypertension, 27(7), 1472–1477. doi:10.1097/hjh.0b013e32832a9ba3 

Global Health Observatory (GHO) data: NCD mortality and morbidity. www.who.int/gho/ncd/mortality_morbidity/en/.

Grundy SM, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the management of blood cholesterol: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019; doi:10.1161/CIR.0000000000000625.

Haapanen N, Miilunpalo S, Vuori I, Oja P, Pasanen M. Association of leisure time physical activity with the risk of coronary heart disease, hypertension and diabetes in middle-aged men and women. Int J Epidemiol. 1997;26(4):739–747.

Halimi J-M, Giraudeau B, Cacès E, Nivet H, Tichet J. The risk of hypertension in men: direct and indirect effects of chronic smoking. J Hypertens. 2002;20(2):187–193

High blood pressure and women. (2016).

High blood pressure. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/high-blood-pressure. 

https://www.heart.org/en/health-topics/high-blood-pressure/why-high-blood-pressure-is-a-silent-killer/high-blood-pressure-and-women

Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, He J. Global burden of hypertension: analysis of worldwide data. Lancet 2005; 365:217–223.

Kirkland EB, Heincelman M, Bishu KG, et. al. Trends in healthcare expenditures among US adults with hypertension: national estimates, 2003-2014. J Am Heart Assoc. 2018;7:e008731.

Kochanek KD, Murphy SL, Xu J, Arias E. Deaths: Final Data for 2017. National Vital Statistics Reports. 2019;68(9). Hyattsville, MD: National Center for Health Statistics.

Mann JF. (2021). Choice of drug therapy in primary (essential) hypertension. https://www.uptodate.com/contents/search. Accessed Dec. 20, 2020

MedlinePlus. (2019). High Blood Pressure. https://medlineplus.gov/highbloodpressure.html 

Mendez MA, Cooper R, Wilks R, Luke A, Forrester T. Income, education, and blood pressure in adults in Jamaica, a middle-income developing country. Int J Epidemiol 2003; 32:400–408.

Mills KT, Bundy JD, Kelly TN, Reed JE, Kearney PM, Reynolds K, et al. Global disparities of hypertension prevalence and control: a systematic analysis of population-based studies from 90 countries. Circulation 2016; 134:441–450.

Natural medicines in the clinical management of hypertension. Natural Medicines. https://naturalmedicines.therapeuticresearch.comSaper RB, et al. Overview of herbal medicine and dietary supplements. https://www.uptodate.com/contents/search.

NHS. (2019). Causes -High blood pressure (hypertension). https://www.nhs.uk/conditions/high-blood-pressure-hypertension/causes/ 

Sandberg K, Ji H. Sex differences in primary hypertension. Biol Sex Differ. 2012;3(1):7.

Saper RB, et al. (2021). Overview of herbal medicine and dietary supplements. https://www.uptodate.com/contents/search. Accessed Dec. 20, 2020

Suzanne RD. (2019). Causes of High Blood Pressure. WebMD. https://www.webmd.com/hypertension-high-blood-pressure/guide/blood-pressure-causes 

The Lancet. 2021. Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants. https://www.thelancet.com/journals/lancet/article/piiS0140-6736(21)01330-1/fulltext#fig6

Thomas G, et al. 2020. Blood pressure measurement in the diagnosis and treatment of hypertension in adults. https://www.uptodate.com/contents/search. 

What is high blood pressure? American Heart Association. https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/what-is-high-blood-pressure#.WrqtReR1rcs.

Whelton PK, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018; doi:10.1161/HYP.0000000000000065.