Hypertension, and its many causes
Blood pressure refers to the tension of blood on the inner lining of the arteries. Arteries carry blood from the heart to different body organs. When this pressure or tension is consistently higher than normal, a diagnosis of "hypertension" is made.
Blood pressure (BP) is defined by two parameters:
● Systolic BP is the pressure in the arteries produced when the heart contracts (ie during a heartbeat).
● Diastolic BP is the arterial pressure during relaxation of the heart between beats.
Blood pressure is reported as systolic BP over diastolic BP (example: 130/80 or 130 over 80).
Untreated high blood pressure increases the strain on the heart and arteries, eventually causing vascular damage or atherosclerosis, and leading to organ damage.
• Heart attack and heart failure
High blood pressure puts extra strain on the heart vessels, called coronaries, and on the heart muscle, increasing the risk of a heart attack and heart weakening, respectively.
• Brain damage
Hypertension can lead to bleeding or to vessel closure in the brain, resulting in a stroke.
• Kidney damage
Similarly, a high BP can damage the kidney vessels, leading to kidney failure.
• Eye damage
High blood pressure can damage the small blood vessels in the eyes, leading to blindness.
• Sexual dysfunction
High BP can affect blood flow to the genital organs, leading to sexual dysfunction in both men and women.
What is considered hypertension?
The following definitions were proposed in 2017, by the American College of Cardiology and American Heart Association:
Normal blood pressure: Less than 120 over less than 80.
Elevated blood pressure: 120 to 129 over less than 80.
● Stage 1: 130 to 139 over 80 to 89
● Stage 2: At least 140 over at least 90
What causes hypertension?
Most adults with hypertension have “primary” hypertension, which means that the cause of the high blood pressure is unknown. However, multiple predisposing factors have been identified:
● Older age
● Genetics: having a family history of hypertension
● Black or Hispanic race
● High salt in diet
● High alcohol consumption
● Sedentary lifestyle.
A small percentage of adults have secondary hypertension, which means that there is an underlying and potentially correctable cause, usually a hormonal or a vascular disorder.
How common is hypertension?
In the United States, approximately 50 per cent of adults have hypertension. Hypertension is more common as people grow older. In fact, it affects more than 75 per cent of adults aged 65 to 74 years, and more than 80 per cent of adults aged 75 years or older.
Despite its wide prevalence and significant adverse health consequences, many people's high BP is not diagnosed and/or not well controlled: according to most studies, BP was in good control in less than half of hypertensive adults.
How do I know I have high blood pressure?
Hypertension is called the “silent killer” as it does not usually cause any symptoms. It is often identified through routine screening. Guidelines recommend that people 40 years and older without a history of hypertension have their BP checked once a year. Such a screening should happen more frequently in people with the risk factors stated above.
For younger people without risk factors, screening every three years or so may be a reasonable approach. If one’s blood pressure is found to be elevated during screening at a doctor’s office, further confirmation with home checks might be needed. BP which increases when collected by a medical professional in an office setting is known as "white coat hypertension".
Which lifestyle choices could help lower blood pressure?
● Lose weight, if overweight
● Choose a healthy diet
● Eat less salt (sodium)
● Be physically active for at least 20 to 30 minutes a day on most days of the week
● Females should limit their alcohol intake to one "standard" drink; men to two
● Quit smoking. While this might not bring your blood pressure down, quitting could lower the chances of a heart attack or a stroke, as tobacco and high BP combined could have an exponentially added deleterious effect.
The key to implementing lifestyle changes is to "start low and go slow"
As an example, if one wants to start an exercise programme, it makes sense to do five minutes of a low-level effort twice a day, then add one minute per session every week thereafter, until one reaches half an hour daily. Afterwards, and while staying limited to 30 minutes per day, one can scale the effort level to make the exercise routine more challenging. The same applies to making diet changes or stopping alcohol and cigarettes.
Weight loss and diet
To lose weight, one has to consistently burn more calories than what they accumulated from eating. To achieve this, one has to either eat less or exercise more. Doing both is obviously more rewarding. While there is no single diet that is right for everyone, studies have shown the clear benefits of a Mediterranean-like diet in decreasing cardiovascular risk. Its staples are:
● Plenty of fruits, vegetables and whole grains
● Beans, peas, lentils and chickpeas
● Moderated amount of nuts
● Fat-free or low-fat milk and yoghurt
● Fish and some chicken
● What not to eat is as important: avoiding processed foods, refined sugar, large amounts of starch, red meat and saturated fat is all critical.
Lastly, one word about reducing sodium intake: since salt is ubiquitous in almost all foods, the most important step one could consider here is to eat less processed meals where most salt tends to come from (foods in cans, boxes, jars and bags), and to minimise eating out in restaurants.
In next week’s article, we will discuss treatment of hypertension: drugs, procedures, and alternative medicine.
Joseph Yammine is a consultant cardiologist at the Bermuda Hospitals Board. He is also the director of the outpatient multi-speciality clinics and director of the Cardiac Computed Tomography programme. He received his post graduate training at the Brigham and Women's hospital, Brown University and the State University of New York. Dr Yammine holds five active American board certifications.
The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.