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What is blood pressure?

As the heart beats, it pumps blood around the body to deliver energy and oxygen and remove waste products. The force with which the circulating blood pushes against the sides of the blood vessels generates blood pressure. Changes in blood pressure can indicate heart function quality and/or artery elasticity.1

A normal blood pressure is less than 120/80 mmHg (the first measure is the systolic pressure and the second, the diastolic pressure). Hypertension is defined as a persistent increase in blood pressure above the normal values, particularly if values are above 130/80 mmHg.2

Hypertension is one of the most common health issues worldwide. In the US, an estimated 1 in 3 adults have blood pressure values above normal.3Hypertension is a risk factor for many other health issues, including cardiovascular diseases (CVDs), kidney disease, and diabetes.

Systolic pressure is the pressure produced in your arteries during the contraction of the heart muscle as it beats.

Diastolic pressure is the remaining pressure in your arteries when the heart muscle relaxes after beating.

What are the symptoms?

In advanced stages symptoms of hypertension may include headaches, dizziness, shortness of breath, chest pain, and palpitations of the heart.4 That said, high blood pressure can be largely asymptomatic, even when it is already producing some damage. This is one reason why regular blood pressure monitoring is so important.5 Hypertension can damage the arteries, heart, kidneys, brain, and eyes. Men can also experience sexual dysfunction.

 What are the causes?

Approximately 90% of hypertension cases have no definitive cause, and they are called essential hypertension.6 In general, this type of hypertension is associated with the following risk factors:

  • Aging
  • Alcohol abuse
  • Being overweight/obese
  • Diabetes or pre-diabetes
  • Genetic predisposition
  • High salt consumption
  • Smoking

Another variant is secondary hypertension, caused by conditions such as1:

  • Adrenal gland tumors
  • Alcohol intoxication
  • Congenital anomalies leading to defects in blood vessels
  • Substance abuse
  • Kidney problems
  • Obstructive sleep apnea
  • Renovascular disease
  • Side effects from medications such as birth control pills, decongestants, over-the-counter pain relievers, cold remedies, and other prescription drugs
  • Thyroid problems
Renovascular disease is a progressive condition that causes narrowing or blockage of the kidney arteries or veins.

How does this topic relate to my microbiome?

Recent evidence suggests links between hypertension and the gut microbiota, although the causes and mechanisms of this relationship are still unclear.7 Metagenomic surveys of the gut microbiota from hypertensive and pre-hypertensive patients showed significantly decreased microbial richness and diversity in comparison with control subjects.8 In these same groups, gut microbiota composition showed an overgrowth of Prevotella and Klebsiella, and changes in microbial activity associated with other gut diseases.

Another study with samples from hypertensive patients also showed that their gut microbiota composition is different from that of non-hypertensive patients, with higher relative amounts of Klebsiella and Streptococcus and lower amounts of Roseburia and Faecalibacterium, and those differences can be used as markers to predict hypertension.9

related to metagenomics, the study of genetic material recovered directly from environmental samples, instead of isolated microorganisms.10

Which diseases/topics are related to blood pressure?

High blood pressure can also occur alongside other conditions, including11:

  • Atrial fibrillation
  • Cerebrovascular disease
  • Chronic kidney disease
  • Diabetes
  • Heart failure
  • Ischemic heart disease
  • Metabolic syndrome
  • Obesity
  • Peripheral artery disease

How can I take action?

It is advisable that you check your blood pressure, routinely. You should consult your healthcare provider if you experience some common symptoms.

Changes in lifestyle are effective in both lowering high blood pressure and preventing hypertension and its consequences. It is advisable that you follow these recommendations11,12:

  • Weight control: target body mass index (BMI) <25 kg/m2 – weight loss is often the most effective way of reducing blood pressure.
  • Healthy diet, including increased fruit/vegetable intake, consumption of fish or fish oils, and reduced cholesterol/saturated fatty acid intake.
  • Quitting smoking and avoiding passive smoke inhalation.
  • Reduced alcohol intake.
  • Regular exercise (30 min or longer, daily if possible), particularly aerobic exercise.
  • Reduced intake of dietary sodium: <6 g/day.

You can also consult with your healthcare provider about whether medication to treat hypertension is indicated.


1. Kokubo, Y., Iwashima, Y., & Kamide, K. (2015). Hypertension: Introduction, Types, Causes, and Complications. In G. Jagadeesh, P. Balakumar, & K. Maung-U (Eds.), Pathophysiology and Pharmacotherapy of Cardiovascular Disease (pp. 635–653). Springer International Publishing.

2. American Heart Association (2016). Understanding Blood Pressure Readings. Retrieved July 2018.

3. Benjamin, E. J., et al. (2018). Heart Disease and Stroke Statistics—2018 Update: A Report From the American Heart Association. Circulation, 137(12), e67–e492.

4. World Health Organization (2013). A global brief on hypertension. Silent killer, global public health crisis. Switzerland.

5. Mancia, G., et al. (2013). 2013 ESH/ESC guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). European Heart Journal, 34(28), 2159–2219.

6. Oparil, S., Zaman, M. A., & Calhoun, D. A. (2003). Pathogenesis of hypertension. Annals of Internal Medicine, 139(9), 761–776.

7. Pevsner-Fischer, M., Blacher, E., Tatirovsky, E., Ben-Dov, I. Z., & Elinav, E. (2017). The gut microbiome and hypertension. Current Opinion in Nephrology and Hypertension, 26(1), 1–8.

8. Li, J., et al. (2017). Gut microbiota dysbiosis contributes to the development of hypertension. Microbiome, 5(1), 14.

9. Mancia, G., et al. (2013). 2013 ESH/ESC guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). European Heart Journal, 34(28), 2159–2219.

10. Eisen, J. A. (2007). Environmental Shotgun Sequencing: Its Potential and Challenges for Studying the Hidden World of Microbes. PLoS Biology, 5(3), e82.

11. Whelton, P. K., et al. (2018). 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. Journal of the American College of Cardiology, 71(19), e127–e248.

12. Oparil, S., et al. (2018). Hypertension. Nature Reviews Disease Primers, 4, 18014.