Brief Answer:
I would explain as follows:

Detailed Answer:
Hello!

Welcome back on HCM!

I would like to explain that dangerous low blood pressure are called values of blood pressure under 90 mmHg for systolic and under 60 mmHg for dyastolic blood pressure.

You should know that every organ needs a sufficient blood supply in order to function properly. During low blood pressure (under the above levels), many organs begin to suffer for blood supply (blood carries Oxygen and food for the cells and takes away CO2 and toxic substances from the cell metabolism).

Let me explain what happens in every organ:

1- The brain. An insufficient blood supply to the brain leads to dizziness, headaches, blurring vision and then fainting and loss of conscience. Fortunately our brain has an autoregulatory mechanisms for low blood pressure up to 60 mmHg for systolic, so it resists more than the other organs to hypoxia.
But when atherosclerosis is present and these autoregulatory mechanisms are not efficient, a stroke can occur.

2- The heart. The heart too has an autoregulatory mechanism for low blood pressure up to 60 mmHg. But lower values, can cause a reduction in the heart function, leading to a lower contraction force. In case of atherosclerosis (like coronary artery disease) a heart attack can occur.

3- The kidneys. The blood supply to the kidney is reduced during low blood pressure, leading to low quantity of urine. When blood pressure is too low, it can cause death of the kidney cells, leading to acute kidney failure.

4- The skin and gastro-intestinal tract. During low blood pressure these organs are the first to reduce the blood flow. Thus the skin becomes pale and the gasto-intestinal tract reduces its work (digestion).

5- The muscles. During low blood pressure, there is insufficient blood supply to the muscles and they do not have fuel enough to work. They become weak and the physical performance is reduced.

All these symptoms can occur earlier if there is chronic damage of the blood vessels from atherosclerosis (such in high blood pressure, diabetes, etc.), leading to a more expressed symptomatology in not too low blood pressure values.

Hope to have clarified some of your uncertainties!

Best wishes,

Dr. Iliri

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