American Fitness Professionals & Associates

By Paul Sorace, M.S., RCEPsm

Hypertension (high blood pressure) affects about 5 million Americans. It is typically known as the silent killer because it usually occurs with no symptoms. That is why it is important to have your blood pressure checked at least annually. While there are many causes of hypertension, most cases are considered primary. That means there is no cure. Secondary hypertension is caused by a medical reason such as a medication, a thyroid deficiency or thyroid tumor, or a damaged blood vessel. This type can often be corrected.

Blood pressure is the result of two forces exerted. The blood being pumped by the heart through the arteries creates one force. The resistance from the arteries to the flow of blood creates the other. There are two numbers that define blood pressure. The top number represents the systolic pressure. This is the pressure in the arteries during the contraction of the heart. The bottom number represents the diastolic pressure. This is the pressure in the arteries when the heart is resting between beats and filling with blood.

A hypertensive reading needs to be recorded on at least two separate occasions for a proper diagnosis. The individual should be seated and relaxed for at least 5 minutes before their blood pressure is checked. It is a myth that it’s worse to have the lower number high. Both numbers are equally important. It also should be noted that only one number needs to be elevated to be considered hypertensive.

So, if someone has a blood pressure of 140/80 mmhg, they are considered hypertensive. When a person has two numbers that fall into different hypertensive stages, they are considered into the higher stage. For example, someone with a blood pressure reading of 180/90 mmhg is considered to have stage 3 hypertension. High Blood Pressure Effects It is the most common cardiovascular disease in the U.S.

It increases risk for target organ disease and complicates many other diseases and disorders. Hypertension can cause stroke, heart attack, heart failure, kidney failure, and peripheral arterial disease. It can complicate diabetes, high cholesterol, and atherosclerosis. It is one of the proposed mechanisms behind the initiation of atherosclerosis. The turbulent blood flow on the arterial walls weakens the arteries and starts the hardening and scarring of the arteries.

Medications

There are many different medications used to treat and control hypertension. Beta- blockers work by sedating the heart to reduce the frequency and force of the contractions and reduce cardiac output. Diuretics eliminate excess water and salt from the body to reduce excess fluid in the body. Calcium-channel blockers prevent calcium from entering the muscle cells in the arteries. This will render the arteries unable to maintain a contraction, which will vasodilate (widen) the arteries. Ace-inhibitors reduce enzymes and hormones in the body that cause vasoconstriction (tightening) of the arteries. These are some of the more common medications used to stabilize blood pressure. Others include alpha-blockers, ace receptor blockers, direct vasodilators, centrally acting drugs, and peripheral acting drugs. It is important to know antihypertsensive medications can effect exercise performance and recovery.

Beta-blockers and some calcium-channel blockers will reduce the exercise heart rate. This will obviously make exercise heart rate a less accurate indicator of intensity. Diuretics can induce dehydration and electrolyte loss (e.g.- potassium). Sweating from exercise can amplify these effects so adequate fluid and electrolyte intake before, during, and after exercise is essential. Medications that vasodialate the arteries can amplify the hypotensive effect resulting from blood pooling after exercise. A prolonged cooldown at the end of an exercise session can prevent exercise-induced syncope (fainting).

Exercise Effects

There are a number of proposed mechanisms by which regular exercise reduces blood pressure. A few include reduced cardiac output, lower levels of serum norepinephrine, higher levels of serum vasodilators, altered renal function, increased insulin sensitivity, lower levels of renin, and weight loss (particularly in the abdominal region). With weight loss, there will be a reduced distance that the heart needs to pump throughout the body. This will reduce the pumping force and in turn blood pressure.

A lowered heart rate will reduce cardiac output and lower blood pressure. Less norepinephrine (adrenaline) will reduce both the force of the heartbeats and the tightening of the arteries. Increased circulating vasodilators (e.g.- prostacyclins) will widen the arteries. Altered renal function can improve the body’s ability to regulate and eliminate excess fluids from the body. Central or abdominal obesity is a risk factor separate from overall obesity.

Aside from the general obesity effect on blood pressure, it also contributes to insulin resistance. Abdominal obesity, through a series of reactions, impairs the liver’s ability to effectively clear insulin from the blood. This can lead to insulin resistance and increased insulin secretion from the pancreas. An increased secretion of epinephrine does this. The side effects are increased heart rate, contractility, and tightening of the arteries, which will lead to increased blood pressure. Reducing abdominal obesity is a priority. There is also the additive effect from daily exercise. That is, after exercise, blood pressure is lowered primarily because of increased blood flow to the muscles and skin. This means less blood flow to the heart and lowered cardiac output.

This lowered pressure is most prominent for several hours after exercise and can still be depressed 12 hours post exercise. By the time the next exercise session occurs, when the pressure is resuming its usual level, it is depressed again. This effect starts to occur with the very first exercise session.

Exercise Prescription \ Program Design

Cardiovascular exercise should be performed for 30-60 minutes, 3-5x per week, at a moderate intensity (e.g.- 60%-75% target heart training zone). Ideally, hypertensives should exercise every day of the week to maximize the additive exercise effect. Low-moderate intensity exercise, 3½ -4 Mets is equally as effective as higher intensities. That would equal 3.5-4.0 mph on a treadmill. The exercise doesn’t even need to be performed all at once. Three 8-10 minute bouts have shown to be equally as effective as one 30-minute session. This has important implications for those who don’t or can’t follow a structured exercise program.

Research on strength training and blood pressure effects are not as definitive as aerobic exercise. As a result, strength training should not be the only form of exercise for lowering hypertension. Rather, it should be a compliment a proper aerobic program. The intensity should not be high but rather moderate. A fitness professional should be sought for safely designing a strength training program for hypertensives. There are safety precautions that need to be followed including intensity, posture, grip, and breathing.

Strength training will result in increased body temperature and increased blood flow to the muscles and skin, which will induce the BP lowering effect discussed earlier. Emphasizing the largest muscle groups (thighs, hips, and torso) will induce the greatest BP reduction. It is important to note that stage 3 hypertension should be first treated with medication(s) before initiating exercise therapy.

Tips to help lower blood pressure

1. Exercise on a regular basis. Physical inactivity increases risk for obesity, diabetes, heart attack, and stroke. 30-60 minutes of physical activity 3-5x per week can be beneficial for prevention and treatment of high blood pressure.

2. Reduce sodium intake (if deemed high). Most Americans eat too much sodium and excessive sodium intake contributes to increased blood pressure due to increased fluid retention in the body.

3. If overweight, lose weight. (explained above)

4. Engage in relaxing (stress buster) activities to manage stress. Chronic stress can lead to poor eating habits, alcohol consumption, smoking, and lack of exercise. Physiologically, hormones are released under stress that can raise blood pressure. Try to find relaxation time each day.

5. If a smoker, quit. Smoking increases stress on the heart and arteries, which increases risk for a stroke and a cardiac event. It also contributes to elevated cholesterol. Talk to your doctor about smoking cessation programs.

6. Avoid excess alcohol consumption. Some research indicates that two drinks per day will raise blood pressure. It is also high in calories. One drink per day should be the limit for hypertensives.

7. Eat for heart health. Eat plenty of vegetables, fruits, fiber, low-fat dairy foods, and foods low in cholesterol. A diet high in potassium, magnesium, and calcium is good for high blood pressure.

8. Discuss with your doctor oral contraceptive use. There is evidence that a woman increases risk for hypertension while on oral contraceptives. This risk is increased if overweight, had hypertension while pregnant, has kidney disease, or a family history of hypertension.