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Do you want to know more? Understanding the blood pressure equation will help find solutions easily.

Blood is the fluid connective tissue, carried to all parts of our body in blood vessels called arteries. The arteries play a key function in providing blood (thus oxygen and energy) to all organs of the body.

The pressure that your heart needs to pump your blood to every corner of your body, this pressure is known as blood pressure.

High Blood Pressure- a condition in which the force of the blood against the artery walls is too high, has no symptoms. Over time, if untreated, it can cause health conditions, such as heart disease and stroke.

Hypertension or high blood pressure is a serious health problem that currently affects nearly 1 billion people worldwide.

When the heart contracts and pushes blood out, blood has some sort of force behind it and as it comes out puts some pressure on the walls of the arteries which can be measured using cuffs placed only around the branchial artery which is a branch of the aorta.

This pressure is divided into two phases:

The systolic phase is where the heart contracts and pushes the blood, and the diastolic phase when the heart relaxes, and the blood is pushed upon the walls. Normal blood pressure is a systolic pressure below 120mmHg and a diastolic value below 80mmHg, but if a patient has measurements between 120 and 139 mmHg for the systolic and measurement from 80 to 89 for diastolic, they may be prehypertensive but not yet considered hypertension. If a patient gets a consistent measurement of 140 and above for systolic and 90 and above for diastolic this is recognized as hypertension.

What factors contribute to blood pressure?

There is an equation that informs you about the contributing aspect.

Blood pressure is equivalent to cardiac output, a kind of output, the volume of blood getting ejected by the heart per meter multiplied by systemic vascular resistance.

Blood Pressure = Cardiac Output X Systemic Vascular Resistance

Systemic vascular resistance called peripheral vascular resistance or total peripheral resistance, is the resistance that blood encounters through blood vessels, determined by the diameter of the length of the blood vessel.

Blood Pressure = Cardiac output is the amount of blood pumped out per minute, while SVR is the resistance the blood faces as it moves through the lumen.

What defines Cardiac output? What are the contributing factors for this?

If the volume of blood pumped out per min, then the contributing factors would be:

Stroke volume is the volume of blood pumped out per contraction and heart rate is the number of times the heartbeat beats. Cardiac output is stroke volume times the heart rate.

Stroke volume is 70ml and the left ventricle contracts 70-75 times in a min, resulting in 5 liters of cardiac output.

Systemic Vascular Resistance (SVR): Blood vessels are hollow, if you have got a blood vessel that has quite a large lumen so it's quite open compared to a blood vessel that's contracted and has a small wound.

During blood moves through this blood vessel which one is going to experience greater resistance? When a blood vessel constricts, it causes the smaller one to experience greater resistance and the larger one to pump harder, resulting in higher SVR and higher blood pressure. Increased cardiac output, SVR, heart rate, and blood pressure all contribute to increased blood pressure.

What are some factors that affect stroke volume?

Stroke volume is determined by blood volume and contractility, as blood needs to be pumped out to contract.

All this concludes when somebody suffers from hypertension and wants to treat it, give them antihypertensive drugs as it is to treat hypertension.

What do those drugs do?

It reduces SVR by dilating blood vessels and heart rate by stopping sympathetic nervous innovation and decreasing blood volume by inhibiting the renin-angiotensin-aldosterone system, which increases blood volume.

Types of hypertension

Primary hypertension can be due to family history, increased salt intake, obesity, stress, or underlying disease.

Secondary hypertension could be due to underlying conditions such as kidney damage, liver cirrhosis, hormonal disorder, or Cushing disorder.

Pregnancy-induced hypertension is a hypertensive disease of pregnancy known as preeclampsia and eclampsia.

White coat hypertension, in which the blood level is above 95% in a physician's office and normotensive outside.

Groups of medicines consumed for treating hypertension

  • Beta blockers

  • Calcium channel blockers

  • ACE inhibitors and ARBs

  • Diuretics

  • Central sympatholytic


Changes in lifestyle are recommended to reduce blood pressure, such as watching your diet, keeping sodium intake low, keeping a home blood pressure log, reducing stress, limiting alcohol consumption, and giving up smoking. Most of these have minimal side effects, but if there are, do get them changed.

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