High Blood Pressure (Hypertension)

High blood pressure (hypertension) is defined as high pressure (tension) in the arteries, which are the vessels that carry blood from the heart to the rest of the body.

Blood pressure measures the force inside the body’s arteries that happens with each heartbeat as blood delivers oxygen-rich blood to every organ and cell.

There are two numbers used to measure pressure during the heartbeat cycle:

• Systole measures the pressure inside an artery when the heart is pumping blood to the body.
• Diastole is the pressure inside the artery when the heart has relaxed to allow blood return.
• Blood pressure is measured in millimeters of mercury (mmHg)

The definition of hypertension is complicated. You can have systolic hypertension, diastolic hypertension, or both.

According to the American Heart Association, in an adult, normal blood pressure is 120/80 or less, but there are different categories of high blood pressure:

• Normal blood pressure – Systolic less than 120 mmHg and diastolic less than 80 mmHg
• Elevated blood pressure – Systolic 120 to 129 mmHg and diastolic less than 80 mmHg
• Hypertension:
  • Stage 1 – Systolic 130 to 139 mmHg or diastolic 80 to 89 mmHg
  • Stage 2 – Systolic at least 140 mmHg or diastolic at least 90 mmHg
    If there is a difference in the category, the higher number determines the level of high blood pressure.

In Europe, hypertension is defined differently. The recommendations of the European Society of Cardiology and the National Institute for Health and Care Excellence in England, hypertension is defined as a systolic blood pressure of 140 mmHg or greater, or a diastolic pressure of 90 mmHg or greater.

Primary hypertension

For most people, the cause of high blood pressure is not known. There are risk factors associated with developing high blood pressure, but it is unknown why.

Secondary hypertension

There are some medical conditions where high blood pressure develops as a complication of that illness, or may be due to a medication intolerance or interaction. A few causes include the following:

• Pregnancy
• Kidney disease
  • Diabetes
  • Polycystic kidney disease
  • Glomerular kidney disease
  • Renal artery stenosis
• Thyroid disease
  • Hypothyroidism or
  • Hyperthyroidism
• Cushing’s Disease
• Hyperaldosteronism
• Sleep apnea
• Coarctation of the aorta
• Obesity
• Medications
  • Prescription pain relievers or birth control pills
  • Over the counter medications
    • adrenalin-like medications
      • ephedrine
      • pseudoephedrine
  • Dietary supplements
    • ma-huang (ephedra)
    • licorice
• Illegal drugs
  • cocaine
  • methamphetamine
  • PCP

Hypertension by itself has NO symptoms. Only when other organs are put under stress because of exposure to elevated blood pressure, either suddenly or chronically, may symptoms arise. High blood pressure is known as the “silent killer” because the damage that is caused to many organs in the body occurs slowly and without the patient’s knowledge. The diagnosis is made by routinely checking and monitoring blood pressure readings over time.

Blood pressure in pregnancy

The body changes in the pregnant woman and so does its response to changes in blood pressure. Normal blood pressure in pregnancy is 120/80, but because of physiologic changes, 90/60 may also be normal. Blood pressures of 130/90, or a systolic reading of 15 mmHg higher than before pregnancy, is concerning. After 20 weeks of pregnancy, a blood pressure reading of 140/90 may signal the presence of preeclampsia, a life-threatening condition.

There are many home blood pressure machines that can be used that can automatically measure blood pressure, but to make the initial diagnosis, blood pressure needs to be measured by a health care provider, ideally in a quiet setting.

While blood pressure is often measured quickly in the office with a provider inflating a blood pressure cuff on the upper arm and listening with a stethoscope to blood flow at the crook of the elbow, accurate blood pressure measurements take time. There are specific steps to be taken by both the patient and provider to take an accurate measurement of the blood pressure.

• The patient should avoid caffeine, exercise, and smoking for at least 30 minutes before measurement.
• The patient should have an empty bladder.
• The patient should relax and sit in a chair with their feet on floor and back supported for at least 5 minutes.
• All clothing covering the location of cuff placement should be removed so that the cuff is resting on bare skin and the cuff should fit appropriately.
• There should be no talking either by patient or the provider during the rest period or during the measurement.
• Blood pressure readings that are taken while the patient is sitting or lying on an examining table are not valid.
• When blood pressure is being taken for the first time, it should be recorded in both arms.
• Blood pressure may be measured either manually, listening with a stethoscope, or by automated machine.

What blood pressure number is more important, systolic or diastolic?

Both systolic and diastolic blood pressure readings are important. Historically, the systolic reading was thought to be more important when it came to risk of complications, like heart attack or stroke. However, current research suggests that both blood pressure numbers are important and blood pressure control should include both systolic and diastolic hypertension.

The diagnosis of hypertension should be made based on blood pressure readings taken by a health care provider. It is recommended that elevated blood pressure readings be documented on at least two separate visits to make the diagnosis.

Can blood pressure spike for no reason?

The blood pressure in the body changes routinely during the day as it reacts and adapts to the environment around it. Blood pressure is affected by the diurnal variation, the routine day/night cycle the body experiences, by emotional and physical stresses of routine daily activity and exercise, by food and drink, and by medication.

• White coat hypertension is the patient’s equivalent of performance anxiety. The worry that accompanies having blood pressure measured, either at a doctor’s office or even at home, may cause blood pressure readings to rise, as a normal response to a surge of adrenaline in the body. The new guidelines on how to take a blood pressure reading are meant to address white coat hypertension.
• Labile hypertension describes the situation where blood pressure increases for a brief period of time due to an outside stress, like anxiety, exercise, or trauma. The rise in blood pressure is short lived.

When is the best time to measure blood pressure?

Once the diagnosis is established, home monitoring is reasonable. Since there is routine and normal fluctuation of blood pressure readings during the day, there is no “best” time to measure it. Instead, it is best to take blood pressure readings at the same time each day to help monitor how well any treatment is working.

The first step in treating high blood pressure is making the diagnosis. Once the diagnosis of hypertension is established, the treatment will be individualized for the patient and will include lifestyle modifications with or without medications.

Blood pressure control is a lifelong commitment to help minimize the risk of complications like heart disease, stroke, and peripheral artery disease. Over that lifetime, treatment may add or subtract medications, but non-medication treatments will always be necessary.

How do you lower blood pressure without medications?

Keeping high blood pressure under control decreases the risk of developing many diseases. It is a lifelong commitment to living a healthy lifestyle and may include the following:

• Weight loss is key to blood pressure control in those who are obese. Blood pressure will fall up to 2 mmHg for every 1 kg (2.2 pounds) lost.
• Aerobic exercise for 40 minutes, 3-4 times per week, plus resistance training (weightlifting and isometrics) will result in lower blood pressure readings within 12 weeks.
• Diet
  • A low salt diet will significantly lower blood pressure. The effect is most pronounced in the middle-aged or elderly, but the beneficial effects of the low sodium diet are seen in all people regardless of age, sex, race, diabetes, or body mass index. The effect is then whether a person takes blood pressure medication or not.
  • Potassium supplement in the diet may be helpful in controlling blood pressure. However, this should be avoided in those with kidney disease, or who are taking medications that affect potassium excretion in the body.
  • The DASH diet (Dietary Approaches to Stop Hypertension) is a healthy diet that can help control blood pressure.
    • high in vegetables, fruits and nuts, fish and poultry, and low-fat dairy
    • low in added sugar and red meat and cholesterol
    • rich in potassium, magnesium, calcium, protein, and fiber
    • low in saturated fat, total fat, and cholesterol.
• Limiting alcohol intake
  • Men with hypertension should have a maximum of two drinks per day.
  • Women with hypertension should have only one drink per day maximum.

Which medication is best to treat hypertension needs to be individualized for each patient. Medical history, current illnesses, other medications and allergies, and lifestyle all need to be considered. As well, there will be trial and error to determine whether a medication is effective and whether there are side effects. Sometimes, more than one medication needs to be prescribed to lower blood pressure to the goal of a normal reading.

The different classes of medication include the following:

Calcium channel blockers

• Calcium helps heart muscle contract (squeeze) strongly and narrows arteries. These medications block calcium from entering heart and artery cells. This allows the heart to squeeze less aggressively and arteries to relax and dilate.
• E.g., amlodipine, diltiazem, nicardipine

Angiotensin-converting enzyme (ACE) inhibitors

• Angiotensin is made in the liver and then converted in the kidneys to cause blood vessels to narrow. Ace inhibitors relax blood vessels causing blood pressure to lower.
• E.g., lisinopril, enalapril, captopril

Angiotensin II receptor blockers (ARBs)

• These medications block the receptors in heart and artery cells preventing angiotension attaching to those cells. The effect of the angiotensin is blocked and blood pressure decreases.
• Eg. losartan, valsartab

Diuretics

• These medications cause the kidneys to remove water and salt from the body; less fluid in the arteries and veins, lowers blood pressure.
• E.g., hydrochlorothiazide, furosemide

Beta blockers

• These medications block the adrenalin receptors in the heart, causing it to beat more slowly and less aggressively. As well, they cause arteries to dilate.
• E.g., metoprolol, atenolol, nadolol
• Beta blockers are no longer recommended to be used as single drug control of hypertension.

How is diastolic hypertension treated?

Isolated diastolic hypertension occurs when the systolic blood pressure reading is normal (120mm Hg or less), but the diastolic reading is greater than 80 mmHg. In younger patients, under the age of 50, diastolic hypertension alone increases the risk of heart disease.

The treatment approach to this condition is the same as systolic high blood pressure.

There are two types of complications related to hypertension, the first is due to a rapid spike in the blood pressure, and the second because of chronic changes that occur in organs subjected to longstanding elevated blood pressures.

Chronic, poorly-controlled hypertension causes damage to the arteries in the body, from the largest, the aorta, to the smallest arterioles that supply blood to every organ in the body. Over time, the risk of damage to every organ increases. Hypertension is one of the major risk factors that can lead to heart attack, congestive heart failure, stroke, peripheral vascular disease, eye, and kidney damage among others.

In a hypertensive emergency, when blood pressure spirals upward out of control, damage to target organs can happen within minutes. There is no threshold blood pressure reading that can trigger organ damage. The diagnosis is made based on the symptoms that present in the patient.

Historically, a blood pressure of 180/120 was considered dangerous and in need of treatment to lower it immediately. That is no longer the approach to care for people whose blood pressure is markedly elevated without symptoms. To be more judicious, treating the blood pressure as an outpatient by gradually lowering the readings using medications.

An exception is made for pregnancy, where an elevated blood pressure of 140/90 needs to be evaluated for the risk of preeclampsia and quickly treated to avoid injury to mother and fetus.

For those who have markedly elevated blood pressures and target organs are acutely failing (e.g., heart attacks, aortic dissections, strokes, kidney failure, eye damage), emergent blood pressure control is a priority. In these situations, there often is no cure, but rather the goal is to minimize the amount of damage that has already occurred.

Can high blood pressure hurt my eyes?

Longstanding, poorly-controlled hypertension can damage the arterioles that supply the eye with blood. This can cause damage to the retina, (hypertensive retinopathy) where the nerves for sight reside. Other retinal diseases can also be caused by chronic hypertension, including occlusion of arteries and veins that supply the eye. Diabetic retinopathy can be made worse by chronic hypertension, and hypertension is also a risk factor for glaucoma and macular degeneration.

It is difficult to prevent hypertension since the cause is uncertain. That said, living a healthy lifestyle, eating well, sleeping well, exercising routinely, avoiding tobacco, and limiting alcohol, may decrease the risk of developing high blood pressure. As well, living healthily, will help minimize the risk of chronic disease should hypertension develop.

Can exercise help lower blood pressure?

Exercise is one of the main ways a person with hypertension can lower high blood pressure, even without taking medications. Recommendations include aerobic exercise for 40 minutes three times a week. In addition, resistance and isometric exercises are helpful in lowering blood pressure.

Can you be physically fit and have high blood pressure?

Hypertension does not discriminate. Being physically fit is an important part of a healthy lifestyle, but it does not prevent high blood pressure.