Sheara currently teaches undergraduate biology courses and has her doctorate in Kinesiology.
Close to one-third of adults have hypertension, or high blood pressure, an all too common cardiovascular disease. As we age, the likelihood that we will develop hypertension increases. Let's quickly review how blood pressure is measured, which will make it easier to understand the categories of blood pressure.
When your blood pressure is read, the systolic pressure represents the pressure in the arteries that is generated when the heart ventricles contract. The diastolic pressure is the pressure in the arteries when the ventricles are relaxing and filling with blood. Pressure is measured in millimeters of mercury, written as mmHg. Normal blood pressure is categorized as less than 120 mmHg systolic pressure and less than 80 mmHg diastolic pressure. Normally, blood pressure will rise and fall as you go through the course of your day, just as your heart rate does.
Hypertension is a condition when your systolic blood pressure is higher than 120 mmHg and your diastolic blood pressure is above 80 mmHg, averaged over time. Sometimes, a patient may have elevated blood pressure in the doctor's office but not at any other time. This is called white coat hypertension and may be credited to a person feeling anxious around doctors in white coats and the sterile environment. In this case, a doctor may prescribe a 24-hour ambulatory monitoring, which you can wear during your normal daily activities. By averaging your blood pressure while you are awake and asleep, a doctor can determine if you are normotensive, an indication of normal blood pressure, or hypertensive.
Stages of Hypertension
If a patient has blood pressure that is consistently above normal, he or she can be further categorized into different stages of hypertension. Here's how doctors classifying blood pressure:
- Normotensive blood pressure: No risk for hypertension (measured as less than 120 mmHg systolic or less than 80 mmHg diastolic)
- Prehypertensive blood pressure: At risk for developing hypertension (measured as 120-139 mmHg systolic or 80-89 mmHg diastolic)
- Stage 1 hypertension: High blood pressure that may be treated with lifestyle changes or medication (measured as 140-159 mmHg systolic or 90-99 mmHg diastolic)
- Stage 2 hypertension: High blood pressure that may require one or two medications (measured as greater than 160 mmHg systolic or higher than 100 mmHg diastolic). This is the most severe form of hypertension.
In the case of comorbidity, or the presence of another chronic illness like diabetes or renal disease, a doctor may categorize a patient as hypertensive even if they are considered prehypertensive.
Symptoms of Hypertension
You most likely would not know you have hypertension. In most cases, a person will be asymptomatic, having no noticeable symptoms, which is why this disease is so dangerous. If hypertension is not detected, it can wreak havoc on your cardiovascular system by putting excess strain on your blood vessel walls and heart. In some very rare cases, a person may develop a sudden onset of hypertension, which causes noticeable symptoms. Preeclampsia during pregnancy and severe kidney disease are examples. A person experiencing a sudden onset of hypertension may experience any combination of symptoms that range from severe headache, nosebleeds, and nausea to neurological symptoms, like confusion and blurred vision. These symptoms are signs that blood pressure is dangerously high and requires immediate medical attention.
Since hypertension is normally unnoticed, it is important to understand the causes so that you can take measures to reduce the likelihood of developing or decreasing the severity of hypertension.
Primary Hypertension: Causes
Hypertension cannot be attributed to a single cause. It is multifactorial, meaning there are genetic and environmental aspects of the disease. There are two types of hypertension: primary hypertension and secondary hypertension. Primary hypertension does not have a clearly identifiable cause. This type of hypertension rarely has any accompanying symptoms and tends to creep up over the years, which is why it has been deemed a silent killer.
Some individuals, especially those who are of African American ancestry, may be genetically inclined to develop hypertension. Primary hypertension is often associated with an individual's lifestyle. Poor diet, especially those high in sodium and fat, increase a person's odds that he or she will develop hypertension, along with habitual drinking and smoking. Additionally, obesity and lack of exercise are linked to hypertension. This is why doctors recommend that people diagnosed with prehypertension or stage 1 hypertension make lifestyle changes to slow or stop the progression of the disease. This can be effective in reducing blood pressure for some people but not all.
Secondary Hypertension: Causes
Secondary hypertension, on the other hand, does have an identifiable cause. Unlike primary hypertension, there tends to be a sudden increase in blood pressure due to an identified disease. Often, secondary hypertension is more severe than primary hypertension, leading to stage 2 hypertension. Secondary hypertension often accompanies severe kidney disease or can occur as a side effect of certain medications. For example, corticosteroids (anti-inflammatory medications), antidiuretics, and oral contraceptives have a side effect of making you retain water. Water retention can lead to swelling in the tissues and increased blood volume.
How does that happen? The water that is retained has to go somewhere, but where? If most of the retained water remains in the blood, it increases blood volume, and the heart has to work harder to distribute it. Think about your mailperson having to carry and distribute 50% more mail on his or her delivery every day and the subsequent physical changes needed to keep up with this load. He or she may bulk up a bit. Although bulking up a bit may seem harmless, the muscular walls of the heart can become thicker and less pliable.
Disorders that limit oxygen availability to parts of the body and taking erythropoietin (EPO) can also increase blood pressure over time. Both conditions result in the production of excessive amounts of red blood cells. How does increased red blood cell concentration increase blood pressure? Increasing the thickness, or viscosity, of blood makes the heart work harder. Think about how much harder you would have to work to walk through a field with mud a foot deep compared to walking through a pond with water a foot deep. It takes more effort for you to move your body through the more viscous fluid. The heart has to contract with more force to distribute that thicker blood to all of the body parts. The increase in force generated by the heart increases the pressure in the arteries.
Hypertension is a disease in the United States that affects almost a third of the population. Many factors contribute to the development and progression of the disease, making it multifactorial in nature. Hypertension is usually asymptomatic, except in rare case caused by preeclampsia or severe kidney disease which can lead to secondary hypertension. This is why it is so important to have blood pressure routinely checked. If you are diagnosed with primary hypertension, your doctor may suggest making lifestyle changes such as changing your diet, exercising, and giving up smoking.
Stages of hypertension include:
- Stage 1 hypertension
- Stage 2 hypertension
To unlock this lesson you must be a Study.com Member.
Create your account
Register to view this lesson
Unlock Your Education
See for yourself why 30 million people use Study.com
Become a Study.com member and start learning now.Become a Member
Already a member? Log InBack