High blood pressure

Carter Hemphill, MD., FACC, is a cardiologist with The Chattanooga Heart Institute.

Carter Hemphill, MD., FACC, is a cardiologist with The Chattanooga Heart Institute.

How common is high blood pressure?

According to the Centers for Disease Control and Prevention (CDC), the prevalence of high blood pressure (hypertension) in the United States is 29% of the adult population.  The prevalence differs by ethnicity and gender and generally increases with age: about 7.5% of adults age 18-39 have hypertension, whereas 63% of adults over age 60 have hypertension.

What causes hypertension?

In rare cases (about 5%), hypertension can be caused by an isolated disease process such as a hormone-secreting tumor.  This is called secondary hypertension.  This form of hypertension can often be cured by treatment of the underlying process.  However, the overwhelming majority of cases of hypertension are due to essential hypertension.  Essential hypertension has a variety of underlying causes, some of which are non-modifiable such as age, gender and genetics.  The aging process is associated with arteriosclerosis (commonly called, “hardening of the arteries”), which causes the blood vessels of the body to become less flexible, thereby increasing systolic blood pressure.  Fortunately, many causes of hypertension can be controlled or eliminated by an individual.  Obesity, cigarette smoking, sedentary lifestyle, excessive salt intake, and excessive alcohol intake may all contribute to essential hypertension.

What can hypertension lead to?

Hypertension is a well-known risk factor for stroke, heart attack and congestive heart failure, kidney failure, vascular disease such as aneurysm formation, and even dementia.  Control of hypertension is an important part of maximizing your healthy lifespan.

Are there noticeable symptoms of hypertension?

In some cases, yes.  Severe hypertension may be associated with headache, visual changes, chest pain, shortness of breath, and sometimes confusion or stroke-like symptoms.  Hypertension associated with these symptoms is referred to as malignant hypertension or hypertensive emergency.  Malignant hypertension can cause irreversible organ damage.  A person who has very high blood pressure (usually a systolic blood pressure >180 mm Hg and/or a diastolic blood pressure >95 mm Hg) and the onset of any of these symptoms should seek emergency medical treatment at the nearest emergency room or by calling 911.  However, generally hypertension does not cause symptoms and can only be diagnosed by a health professional through screening.  Unfortunately, even asymptomatic patients can suffer severe long-term adverse effects from hypertension such as heart failure, kidney failure, stroke or heart attack. 

What are typical blood pressure ranges and when should you be concerned?

While the answer to this question is somewhat muddied by different guidelines from different professional organizations, the most widely accepted value for “normal” blood pressure is <120/80 mm Hg.  Blood pressure values between 120/80 mm Hg and 129/<80 mm Hg are referred to as, “elevated blood pressure” or “pre-hypertension”, while values >130/80 mm Hg indicate the presence of hypertension which may require treatment with lifestyle modification or medication.  Guidelines such as those published by the American College of Cardiology and American Heart Association differ from the most recent guideline published by the Eighth Joint National Committee (JNC8), making the precise number at which medications should be started a matter of debate.  The most relaxed guidelines recommend that medications be started if necessary to maintain blood pressure <140/90mmHg in patients younger than 60 years of age and in those with diabetes or chronic kidney disease.  A blood pressure goal of <150/90mmHg is allowed for patients older than 60 years of age without diabetes or chronic kidney disease.  It should be noted that important recent evidence suggesting that a lower blood pressure target is beneficial has not been incorporated into these more relaxed guidelines.  It is likely that these guidelines will be updated (and hopefully simplified and brought into harmony) in the near future.

It is important to bear in mind that blood pressure will fluctuate over the course of the day: these blood pressure targets should be applied to average blood pressure readings.  In my opinion, blood pressure goals should be tailored to each individual patient depending on other medical conditions which they may have and taking into consideration whether they experience unpleasant side-effects of treatment. 

The following may be a risk factor for high blood pressure

  • Stress: While it is well-known that stressful situations can cause temporary spikes in blood pressure through activation of the sympathetic nervous system and the release of stress hormones (catecholamines) into the blood, it is not clear whether stress can cause sustained hypertension of the sort that leads the illnesses we have previously discussed.  Obviously, it is good to avoid unnecessary stress.  Having said that, stress is an unavoidable part of life.  It is the decision of every person how to best balance the need to avoid stress with the need to have a productive and satisfying life.
  • Being overweight: The association between hypertension and being overweight or obese is well documented.  Excess weight is also a major risk factor for the development of diabetes.  People who exercise and maintain an ideal body weight are much less likely to develop hypertension at a young age.  Overweight or obese people who are able to lose enough weight and maintain the weight loss are often able to reduce their blood pressure or even come off of some or all of their antihypertensive medications. 
  • Lack of sleep: There is some medical evidence to suggest that sleep deprivation, interrupted sleep patterns or sleeping less than 6 hours per night may cause elevation of blood pressure.  Perhaps just as importantly, it is well documented that sleep disordered breathing (including common conditions such as obstructive sleep apnea) can increase blood pressure.  Sleep disordered breathing can also cause stroke and heart arrhythmias. 
  • Gender: In the United States, and probably in most other populations, men are much more likely to develop hypertension.  The gap in the prevalence of hypertension between men and women narrows with age.
  • Eating processed foods and foods high in sugar: A diet high in sodium is very likely to contribute to hypertension.  In the Unites States, most dietary sodium comes from processed or commercially prepared foods rather than salt from a salt shaker.  Reducing dietary sodium, usually by reducing consumption of processed foods, is one of the first lifestyle modifications I recommend for control of blood pressure.  While it is not clear that refined sugar directly contributes to hypertension, diets high in refined sugar are also likely to be high in calories.  Over time this will probably result in weight gain, which can lead to hypertension as we have discussed.
  • Taking birth control pills or antidepressants: Oral contraceptives, particularly estrogen/progestin combinations, are a well-known cause of hypertension.  Women who have hypertension or who develop hypertension after starting an oral contraceptive should consider switching to a progestin-only regimen or using an intrauterine device (IUD).  A considerable number of antidepressant medications can cause hypertension including venlafaxine, bupropion, tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs).  Patients who suffer from both depression and hypertension should discuss the choice of an antidepressant medication with a psychiatrist or other qualified health provider. 

What are some ways to reduce your risk and manage your blood pressure?

Maintaining an active lifestyle with frequent cardiovascular exercise and maintaining a healthy body weight through a well-balanced diet are probably the two most important things you can do to reduce the risk of developing hypertension.  Some people are particularly sensitive to dietary salt.  A low sodium diet (<2,000-2,500 mg of sodium per day) can often have a significant beneficial effect for these patients.  Unfortunately, most people can expect to develop some degree of hypertension as they age.  Medications are an important part of controlling blood pressure when lifestyle changes are inadequate.  Fortunately, there are many different blood pressure medications from which to choose.  Nearly all patients can achieve good blood pressure control with no or minimal side effects with the use of an appropriate medication regimen. 

Best wishes for good health and long life!  

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