Understanding Hypertension, 'The Silent Killer'

I monitor and evaluate 50 patients’ medication regimens a day on the orthopedic floor. About 60% of those patients have hypertension and will be on at least two to three medications to control their blood pressure. 

The standard of practice for blood pressure control is based on the JNC 8 Guidelines for the Management of Hypertension of Adults. These guidelines recommend that adults over 60 years of age should be treated with medications if their blood pressure is greater than 150/90 mmHg and 140/90 mmHg if the patient is under age 60.  The FAA is a little bit more lenient in their regulatory definition of hypertension.  If the applicant has a blood pressure no higher than 155/95, with or without medication, any class of medical certificate can be issued by an aviation medical examiner. 

What is all the hullaballoo about when talking about hypertension?  Hypertension is called “The Silent Killer” because the heart is working hard to send blood through arteries in the body that may not be as soft and pliable as they were in younger years.  The blood supply is still getting to the brain and other vital organs and everything seems fine for many years. The body gets used to this vascular stress, but over the long run multiple organ systems can sustain serious damage.

Untreated high blood pressure puts you at risk for kidney disease, heart failure, peripheral vascular disease, heart disease and cerebrovascular disease (stroke), the two latter conditions being among the leading causes of death in the United States. About 75 million Americans, 1 in 3 adults, have high blood pressure.  These associated diseases make hypertension a very costly disease to treat, almost $49 billion a year! This information comes from the Center of Disease Control and Management (2015) and the National Center for Health Statistics (2013).

Risk factors for high blood pressure are smoking, obesity, eating foods high in sodium, not exercising, and drinking too much alcohol. A study in 2017, done at the Boston University School of Medicine, evaluated and monitored 2,632 men and women with normal blood pressure, ages between 30 and 64 years, for 16 years, who ate a low sodium (less than 2.5 grams of sodium per day) diet versus a diet of greater than 2.5 grams of sodium per day. Interestingly, the results showed that the study participants in the low sodium group had a higher blood pressure than the high sodium group. It is now felt that eating high amounts of complex sugars (prevalent in many Americans’ diets) is the biggest culprit in high blood pressure. I have heard and read that if you lose 10% of your body weight, you will drop your blood pressure numbers by 10%. This is not based on scientific study, but is a general observation.

Most pilots and student pilots have confided in me that they get “White Coat Syndrome” while in the AME’s office. They get excited seeing a physician, nurse practitioner, or physician’s assistant in a white lab coat and their blood pressure goes up. I believe this is due to the fear of finding something bad, which rarely happens. Every pilot or student worries that if their blood pressure is elevated they will be disqualified from getting their medical certificate. Do not let them take your blood pressure right after arriving in the exam room. Wait five or ten minutes to relax. I recommend thinking pleasant thoughts of a beautiful flight you made. Then let the kind folks at your physician’s or AME’s office check your blood pressure. The nurse or physician will inflate the cuff and get a reading after a few seconds.  You will be told two numbers, a systolic reading and a diastolic reading. The systolic blood pressure measures the pressure in your blood vessels caused by the heart contracting. The diastolic pressure is the pressure in the vessels between beats when the heart is relaxing and filling the lower chambers, the ventricles, with blood.

I am going to take blood pressure to a more technical level for a few moments. You may want to get up and stretch or go get your favorite libation at this time before reading. The formula that I learned in pharmacy school for blood pressure is: Blood Pressure = cardiac output x resistance. Cardiac output is the volume of blood that gets pumped out of the heart. Cardiac output is heart rate x stroke volume. Stroke volume is the amount of blood that gets pumped out of the left ventricle for each beat. Resistance is based on the length of the vessel, which is constant, and the diameter of the vessel. Think of it as a pipe and you have a normal flow of water through it.  This metaphor would be a normal blood pressure. Now, let's decrease the diameter of the pipe and put the same amount of water through it.  Now there is resistance through this pipe.  This is what happens in high blood pressure.  The heart rate goes up and the stroke volume goes up and the resistance goes up.

Blood Pressure = Heart rate x stroke volume x resistance.

There is a whole big toolbox of medications that can be prescribed to help. Back in the 70’s, the physician would prescribe a diuretic like furosemide (Lasix®, which got its name because it Lasts Six Hours) or hydrochlorothiazide (Diuril®). These medications would rid the body of sodium, water, chloride and potassium. You always have to know where the bathrooms are when taking these medications.

Then along came ACE Inhibitors, captopril (Capoten®), lisinopril (Zestril®) and ramipril (Altace®) that have been shown to decrease mortality, protect kidneys and decrease the risk of stroke by blocking vasoconstrictive neurohormones, and cause the elimination of water and sodium. Beta blockers decrease heart rate and blood pressure by blocking the beta-receptors that are exposed to epinephrine (you may know this as adrenaline). If the beta-receptors are not blocked, heart rate and blood pressure go up. Examples of Beta blockers are propranolol (Inderal®), metoprolol tartrate (Lopressor®) and carvedilol (Coreg®). For all of you texters out there, you will notice all beta blockers end in Laughing Out Loud (LOL).

As an added note, when patients are prescribed an anti-hypertension medication they usually feel lousy the first couple of days after starting their medication. Now the brain is not receiving all that blood and you feel like just lying on the couch all day. Eventually this passes as your body gets used to the new medication and you get the benefits of a well-controlled blood pressure. 

Take your blood pressure on a regular basis. Yes, even you youngsters out there.  Exercise at least 30 minutes, five times a week and eat a healthy diet. Blood pressure is influenced by two big factors: age and lifestyle. We cannot control aging, but we can control lifestyle. If I had a say, I would make all fast food expensive and healthy food cheap; ban cigarettes; have bathrooms one mile away from where we are, and sit on pogo sticks! Please put me out of business and keep your blood pressure under control.

Larry M. Diamond, PharmD, CFII

Larry Diamond has a Doctor of Pharmacy Degree and has been a pharmacist for 37 years. Larry’s pharmacy practice has been as a Clinical Pharmacy Specialist in Cardiology, Orthopedic Surgery Specialist and most recently Clinical Pharmacy Coordinator. He is a CFII, a pilot for 33 years and has been an AOPA member since 1984.

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