Effects of high versus low blood pressure on the human body

In order to survive and function properly, tissues and organs need the oxygenated blood that the circulatory system carries throughout the body.

When the heart beats, it creates pressure that pushes blood through a network of tube-shaped blood vessels, which include arteries, veins, and capillaries. This pressure — blood pressure — results from two forces: The first force (systolic pressure) occurs as blood pumps out of the heart and into the arteries that are part of the circulatory system.

The second force (diastolic pressure) is created as the heart rests between heartbeats.

These two forces are each represented by numbers in a blood pressure reading.

Thus blood pressure measurement takes into account how much blood is passing through your blood vessels and the amount of resistance the blood meets while the heart is pumping.

High blood pressure, or hypertension, occurs when your blood pressure increases to unhealthy levels.

Hypertension typically develops over the course of several years. Usually, there aren’t any symptoms.

A few people with high blood pressure may have headaches, shortness of breath, or nosebleeds, but these signs and symptoms are not specific and usually do not occur until high blood pressure has reached a severe or life-threatening stage.

High blood pressure can cause damage to your blood vessels and organs, especially the brain, heart, eyes, and kidneys.

The following five categories define blood pressure readings for adults:

• Healthy: A healthy blood pressure reading is less than 120/80 millimeters of mercury (mm Hg).
• Elevated: The systolic number is between 120 and 129 mm Hg, and the diastolic number is less than 80 mm Hg.

Doctors usually don’t treat elevated blood pressure with medication. Instead, your doctor may encourage lifestyle changes to help lower numbers.

• Stage 1 hypertension: The systolic number is between 130 and 139 mm Hg or the diastolic number is between 80 and 89 mm Hg.
• Stage 2 hypertension: The systolic number is 140 mm Hg or higher, or the diastolic number is 90 mm Hg or higher.
• Hypertensive crisis: The systolic number is over 180 mm Hg, or the diastolic number is over 120 mm Hg. Blood pressure in this range requires urgent medical attention.

If any symptoms such as chest pain, headache, shortness of breath, or visual changes occur when blood pressure is this high, medical care in the emergency room is needed.

The primary way that high blood pressure causes harm is by increasing the workload of the heart and blood vessels — making them work harder and less efficiently.

Over time, the force and friction of high blood pressure damage the delicate tissues inside the arteries.

In turn, LDL (bad) cholesterol forms plaque along tiny tears in the artery walls, signifying the start of atherosclerosis.

The more the plaque and damage increase, the narrower (smaller) the insides of the arteries become — raising blood pressure and starting a vicious circle that further harms your arteries, heart, and the rest of your body.

This can ultimately lead to other conditions ranging from arrhythmia to heart attack and stroke.

You can make simple lifestyle changes to help manage and improve your blood pressure.

Some of the steps you may want to take are: lose extra pounds and watch your waistline, exercise regularly, eat a healthy diet, reduce sodium in the diet, limit the amount of alcohol, quit smoking, cut back on caffeine, reduce stress,  monitor blood pressure at home and see the doctor regularly.

In light of the above, low blood pressure might seem desirable. However, for many people, abnormally low blood pressure can cause dizziness and fainting.

Low blood pressure, also called hypotension, is blood pressure low enough that blood flow to the body’s organs is inadequate and symptoms and/or signs of low blood flow develop. In severe cases, low blood pressure can be life-threatening.

A blood pressure reading lower than 90 millimeters of mercury (mm Hg) for the top number (systolic) or 60 mm Hg for the bottom number (diastolic) is generally considered low blood pressure.

Some types of low blood pressure include Low blood pressure on standing up (orthostatic or postural) hypotension), Low blood pressure after eating (postprandial hypotension), Low blood pressure from faulty brain signals (neurally mediated hypotension), Low blood pressure due to nervous system damage (multiple system atrophy with orthostatic hypotension).

The causes of low blood pressure can be pregnancy, large amounts of blood loss through injury, impaired circulation, weakness and a state of shock that sometimes accompanies dehydration, anaphylactic shock, a severe form of allergic reaction, infections of the bloodstream, endocrine disorders such as diabetes, adrenal insufficiency, and thyroid disease, dehydration.

Depending on the type of low blood pressure you have, you may be able to relieve some of your symptoms by:

• Eating a healthy diet with fewer carbohydrates and smaller meals.
• Drinking more water and avoiding alcohol.
• Getting up slowly after you’ve been sitting or lying down.
• Focusing on breathing a few times before you change position.
• Wearing compression stockings.

By Kiran Bahrus Chimnani