High blood pressure is a common condition in which the long-term force of the blood against your artery walls is high enough that it may eventually cause health problems, such as heart disease.
Blood pressure is determined both by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure.
You can have high blood pressure (hypertension) for years without any symptoms. Even without symptoms, damage to blood vessels and your heart continues and can be detected. Uncontrolled high blood pressure increases your risk of serious health problems, including heart attack and stroke.
High blood pressure generally develops over many years, and it affects nearly everyone eventually. Fortunately, high blood pressure can be easily detected. And once you know you have high blood pressure, you can work with your doctor to control it.
High blood pressure leading to a diagnosis of hypertension will occur only when readings stay above normal all of the time.Having high blood pressure for a short amount of time is normal.
Blood pressure has a natural variation – it lowers during sleep and rises on awakening. It also rises in response to excitement, anxiety and physical activity.
The disease burden of high blood pressure is a growing problem worldwide. The increases are blamed on lifestyle factors, including:
- Physical inactivity
- A salt-rich diet through processed and fatty foods
- Alcohol and tobacco use.
Hypertension is a chronic elevation of blood pressure that, in the long-term, causes end-organ damage and results in increased morbidity and mortality. Blood pressure is the product of cardiac output and systemic vascular resistance. It follows that patients with arterial hypertension may have an increase in cardiac output, an increase in systemic vascular resistance, or both. In the younger age group, the cardiac output is often elevated, while in older patients increased systemic vascular resistance and increased stiffness of the vasculature play a dominant role. Vascular tone may be elevated because of increased α-adrenoceptor stimulation or increased release of peptides such as angiotensin or endothelins. The final pathway is an increase in cytosolic calcium in vascular smooth muscle causing vasoconstriction. Several growth factors, including angiotensin and endothelins, cause an increase in vascular smooth muscle mass termed vascular remodelling. Both an increase in systemic vascular resistance and an increase in vascular stiffness augment the load imposed on the left ventricle; this induces left ventricular hypertrophy and left ventricular diastolic dysfunction.
In youth, the pulse pressure generated by the left ventricle is relatively low and the waves reflected by the peripheral vasculature occur mainly after the end of systole, thus increasing pressure during the early part of diastole and improving coronary perfusion. With ageing, stiffening of the aorta and elastic arteries increases the pulse pressure. Reflected waves move from early diastole to late systole. This results in an increase in left ventricular afterload, and contributes to left ventricular hypertrophy. The widening of the pulse pressure with ageing is a strong predictor of coronary heart disease.
The autonomic nervous system plays an important role in the control of blood pressure. In hypertensive patients, both increased release of, and enhanced peripheral sensitivity to, norepinephrine can be found. In addition, there is increased responsiveness to stressful stimuli. Another feature of arterial hypertension is a resetting of the baroreflexes and decreased baroreceptor sensitivity. The renin–angiotensin system is involved at least in some forms of hypertension (e.g. renovascular hypertension) and is suppressed in the presence of primary hyperaldosteronism. Elderly or black patients tend to have low-renin hypertension. Others have high-renin hypertension and these are more likely to develop myocardial infarction and other cardiovascular complications.
In human essential hypertension, and experimental hypertension, volume regulation and the relationship between blood pressure and sodium excretion (pressure natriuresis) are abnormal. Considerable evidence indicates that resetting of pressure natriuresis plays a key role in causing hypertension. In patients with essential hypertension, resetting of pressure natriuresis is characterized either by a parallel shift to higher blood pressures and salt-insensitive hypertension, or by a decreased slope of pressure natriuresis and salt-sensitive hypertension.
There’s a common misconception that people with high blood pressure, also called HBP or hypertension, will experience symptoms such as nervousness, sweating, difficulty sleeping or facial flushing. The truth is that HBP is largely a symptomless condition. If you ignore your blood pressure because you think symptoms will alert you to the problem, you are taking a dangerous chance with your life. Everybody needs to know their blood pressure numbers, and everyone needs to prevent high blood pressure from developing.
Diagnosing High Blood Pressure
High blood pressure is often called a “silent disease” because you usually don’t know you have it; there may be no outward symptoms or signs, so monitoring your blood pressure is critical.
Tests for High Blood Pressure
The only way to tell whether you have high blood pressure is to have your blood pressure measured with a blood pressure cuff (sphygmomanometer).
Changing your lifestyle can go a long way toward controlling high blood pressure. Your doctor may recommend you eat a healthy diet with less salt, exercise regularly, quit smoking and maintain a healthy weight. But sometimes lifestyle changes aren’t enough.
In addition to diet and exercise, your doctor may recommend medication to lower your blood pressure.
Your blood pressure treatment goal depends on how healthy you are.