WHAT IS HYPERTENSION?
Hypertension is derived from two root words; Hyper meaning High and Tension meaning Pressure. Hypertension simply means high blood pressure. Pressure is the force generated when the heart contracts and pump blood through the blood vessels that conduct the blood to various parts of the blood. Although hypertension does not mean or result from excessive emotional tension, but evidence shows that stress and emotional tension do cause increase in blood pressure, and if continuous, could be sustained. High blood pressure is therefore generally defined as a blood pressure exceeding 140/90mmHg confirmed on multiple occasions. The top number (140) is called the SYSTOLIC PRESSURE, and it represents the pressure in the blood vessels (arteries) as the heart contracts and pump blood into circulation. The bottom number (90) is called DIASTOLIC PRESSURE, and it represents the pressure in the blood vessels as the heart relaxes after contraction. These figures measured in millimeters of Mercury (mmHg) reflect the highest and lowest pressures the heart and blood vessels are exposed to during circulation. The generally accepted normal value for blood pressure is 120/80mmHg. Above this value but less than 140/90mmHg is not considered to be hypertensive yet but signals danger, it is therefore called High normal.
An elevation of the blood pressure (Hypertension) increases the risk of developing Heart (Cardiac) diseases such as Heart Failure and Heart attack, Kidney diseases, Vascular diseases like athelosclerosis (hardening and narrowing of blood vessels), Eye damage and Stroke (brain damage). These complications called End organ damage arise as a result of long standing (chronic) hypertension. But victims of hypertension are not aware, at an early stage, that they have the disease, until these complications start appearing. This is because hypertension shows virtually no signs/symptoms at the early stage. For this reason, it is generally referred to as the ‘Silent Killer’.
The damage caused by hypertension increases in severity as the blood pressure increases. Based on this hypertension can be classified as follows:
CATEGORY SYSTOLIC(mmHg) DIASTOLIC(mmHg) Normal Less than 130 Less than 85 High Normal 130 – 139 85 – 89 Mild Hypertension 140 – 159 90 – 99 Moderate Hypertension 160 – 179 100 – 109 Severe Hypertension 180 – 209 110 – 119 Very Severe Hypertension Greater than 210 Greater than 120
Borderline Hypertension is defined as mildly elevated blood pressure that is found to be higher than 140/90mmHg at some times and lower than that at other times.
Patients with borderline value need to have their blood pressure monitored more frequently. They also need to assess end organ damage to be aware of the significance of their hypertension.
It should, however, be emphasized that patients with borderline hypertension have a higher tendency to develop a more sustained hypertension as they get older. They stand a modest risk of having heart related diseases. A close monitoring of their blood pressure and lifestyles could be very useful in this regard.
WHITE COAT HYPERTENSION
A single elevated blood pressure reading in the doctor’s office could be misleading, because the elevation might only be temporary. Evidence over the years has shown that anxiety related to the stress of the examination and fear of the result often result in blood pressure elevation noticed in the doctor’s office only. Infact, it has been suggested that one out of every four persons thought to have mild hypertension, actually may have normal blood pressure outside the physician’s office. This sort of elevated blood pressure noticed in the physician’s office is called ‘White Coat Hypertension’. Suggesting that the white coat, symbolic of the physician, induces the patient’s anxiety and a passing increase in blood pressure. Accordingly, monitoring of blood pressure at home, when in a more relaxed state of mind, can provide a more reliable estimate of the frequency and/or consistency of blood pressure changes.
WHAT CAUSES HYPERTENSION?
The Blood pressure is determined by two major parameters; Cardiac output i.e. the volume of blood pumped by the heart, and the Total peripheral resistance i.e. the resistance of the blood vessels through which blood flows. Hypertension is therefore an end result of either increased force of pumping by the heart, or constriction/narrowing of blood vessels causing increased resistance to blood flow or both. Using the cause of hypertension as a yardstick, two major types of hypertension can be described;
The former also called Primary or Idiopathic hypertension is by far the most prevalent type of hypertension. It accounts for over 90% of all hypertension cases. No clear cut cause(s) can be identified for this type of accommodation, hence the name Idiopathic.
The later accounts for less than 10% of all cases. In this case, the hypertension is secondary to an existing abnormality in one or more systems or organs of the body. The most common causes are related to kidney and hormonal problems. The persistent uncontrolled use of contraceptives, especially in females over 35years of age fall under hormonal causes of hypertension.
Since no clear-cut cause(s) can be adduce for the most common types of hypertension, as with the case with most non-communicable diseases, we therefore talk in terms of ‘Risk Factors’ and not causes. These Risk Factors are actions/inactions that increases chances of getting a disease. Several researches over the years have shown that some factors are directly or indirectly related to the occurrence of hypertension. Some of the factors include:
HEREDITARY: High blood pressure tends to run in some families and races. It is believed that some inherited traits predispose some people to hypertension. For example, high blood pressure tends to be more prevalent in blacks than whites.
A family history of hypertension increases one chances of high blood pressure. Regular monitoring of blood pressure becomes very vital. HIGH SALT INTAKE: High intake of Sodium Chloride (table salt) has being linked to high blood pressure. The condition develops mostly in societies or communities that have a fairly high intake of salt, exceeding 5.8grams daily. In fact, salt intake may be a particularly important factor in relation to essential hypertension that is associated with advancing age, black racial background, hereditary susceptibility, obesity and kidney failure. Research has shown that:
a. Rise in blood pressure with age is directly related to increase level of sat intake, especially in blacks.
b. People who consume little sodium chloride develop no high blood pressure when they consume more, hypertension appears.
c. Increased Sodium is found in the blood vessels and blood of most hypertensives.
Cutting down on salt intake is therefore a reasonable step in preventing hypertension
A close relationship exists between hypertension and obesity. In fact it is believed that most hypertensives are more than 10% overweight. Fat accumulation in the trunk or abdomen is not only related to hypertension but also to diabetes and hyperlipideamia (excess fat in the body). Obesity can contribute to hypertension in several ways. For one thing, obesity leads to a greater output of blood, because the heart has to pump more blood to supply the excess tissues. The increased cardiac output then can raise the blood pressure. For another thing, obese hypertensive individuals have a greater stiffness (resistance) in the peripheral arteries throughout the body. Finally, obesity may be associated with a tendency for the kidneys to retain salt in the body. Weight loss may help reverse problems related to obesity while also lowering blood pressure. It has been estimated that the blood pressure can be decreased 0.32mmHg for every 1kg (2.2pounds) of weight loss.
The International standard for measuring overweight and obesity is based on a value called BODY MASS INDEX (BMI). This value is derived by dividing the body weight (in Kilograms) by the square of height (in Metres).
i.e. BMI = Body weight (Kg)
Height2 (Metres). Note: 1ft = 0.305metres. For adults, a BMI less than 25kg/m2 is preferred. 25 – 29kg/m2 is considered overweight and above 30kg/m2 is Obesity.
LACK OF EXERCISE:
Sedentary normal individuals have a 20 – 50% higher risk of developing hypertension when compared to very active individuals. Exercise lowers both systolic and diastolic blood pressures. For example dynamic exercises such as brisk walking or jogging, swimming or bicycle ridding for 30 – 45mins daily or 3-5times a week may lower blood pressure by as much as 5 – 15mmHg. Moreover, there appears to be a relationship between the amount of exercise and the degree to which blood pressure is lowered. Thus, to a point, the more you exercise, the more you lower your blood pressure. Provided you do not over strain yourself. Normally, a particularly type of exercise is started, and gradually built up to a satisfactory level over time. Regular exercise reduces blood pressure, burn out unnecessarily fat and also makes the body healthier.
ALCOHOL AND SMOKING:
These two constitute the social factors most related to high blood pressure. People who drink alcohol excessively (over two drinks per day) have a one and half to two times increase in the frequency of hypertension. The association between alcohol and high blood pressure becomes particularly noticeable when the alcohol intake exceeds the above per day. Moreover, the connection is a dose related phenomenon. In other words, the more alcohol consumed, the stronger the chances of hypertension. This, probably will explain the prevalence of hypertension in populations where alcohol consumption is a habit.
Although smoking increases the risk of vascular complications (for example, heart diseases and stroke) in people who already have hypertension, it cannot be directly linked with increase in the development of hypertension. Nevertheless, smoking a cigarette can repeatedly produce an immediate, temporary rise in blood pressure of 5 – 10mmHg, but a permanent increase cannot be established. However, it is known that some substances in cigarette, e.g. nicotine, alters the composition of the blood and also affects the blood vessels.
Smoking and alcohol control are integral part of any effort towards the primary control of cardiovascular diseases in any population. STRESS: Although the role of stress and other emotional factors in hypertension is difficult to define. However, it is known that stress causes a physiological rise in blood pressure and this could be sustained if the stress becomes chronic (prolonged).
A STICH IN TIME
Since lifestyle components such as dietary patterns, obesity, physical activity, alcohol and smoking have been recognized as important risk factors, steps to reduce the occurrence of hypertension or to alleviate the condition (for those who are hypertensives) should involve lifestyle modification.
Dietary modifications include restricting salt intake cutting down or cutting out alcohol, reduced fat consumption, and reducing weight if overweight. The American Heart Association recommends a daily consumption of less than 6grams of table salt for normal individuals, and less than 4grams for hypertensives.
A regular exercise program such as brisk walking, jogging, swimming, cycling e.t.c. for 30 – 45mins daily or 3-5 times a week could be very helpful.
Conclusively, it is very important to remember that the only way to know if one’s blood pressure is on the high side is by taking your blood pressure frequently. Normally, your doctor would do that for you. But for a more consistent and reliable monitor of blood pressure, a self-operated blood pressure monitor is crucial. Being very handy and always around, it allows you to follow up your blood pressure regularly and report an increase immediately.
Finally, always remember the WHO slogan “Know your Blood Pressure, if it’s high have it treated”. A healthy Heart adds life to years. A stitch in time, they say, saves nine.