Blood and Health: Simple Engineering Explanation

Since my graduation with bachelor of Mechanical engineering over a dozen year ago, I haven't learnt anything more amazing and interesting than what I'm about to explain. Engineering is versatile as a career. Its curriculum is robust as a subject. I wrote about this in my book in 2015. https://www.amazon.com/Merits-Engineering-Engineers-Peace-lifeseries-Book-ebook/dp/B07J3LJB8X. Despite all I said about the profession as all professions combined in one, my latest exposure had revealed there is much to know about how engineering explains all life phenomenon. 

So, I begin. The greatest thing that happens inside a man's body and keeps him alive is flow. In layman term, flow is movement or transportation of fluid. And again, in simple term, fluid is either gas (air, breathed in and out) or liquids.

Blood Flow

The major liquid flowing ceaselessly in our body is the blood. It is critical to understand that other transport materials in human system depends on blood flow. Hence, the first indicator of health is smooth blood flow. The first signal of complications is impaired or distrupted flow of blood. The flow is impaired when it is too fast or too slow. This is why on first arrival at the hospital, they check blood pressure and temperature. Both are connected to slow, normal or fast blood flow rate. You shall understand later.

Body veins and Vessels

If anything flows, there must be a path or channel through which it does so. Our body is made of hundreds of veins and vessels. These serve as flow path for blood. They are like pipes through which water flows through various sections of our house. Just like these water pipes are connected, veins and vessels are also inter-connected in a complex network. More so, they are in different sizes. We have them in big, small or narrow diameters. What is meant by diameter is the size of the holes at the opening and closing ends of these veins and vessels. Those with narrowest or thinnest radius (half of diameters) are called capillaries.

Beside diameters, they also have different length i.e how long they are. The veins at the extreme part of the body like fingers are shorter and thinner.

Factors affecting Blood Flow

I earlier said blood must flow normally for us to be healthy. Then, factors that affect blood flow are:

1. Diameters (radius of vessels and veins)

2. Length of vessels and veins

3. Blood viscosity

I've explained the first two. Now viscosity.

Blood viscosity

In layman term, viscosity is how thick or light a fluid is or how fast is it to flow. If a substance is thick and does not flow quickly or easily, it implies that its viscosity is higher. We say such substance is more viscous than the one that flows fast and easily. For instance, water is less viscous (having lower viscosity) than honey. Conversely, we can also say honey is more viscous (thicker or slow flowing) than water.

Blood is thicker than water because it is made of plasma (90%water) plus some other substances. The more the quantities of these other substances in the blood, the thicker the blood and lesser the flow. And the less of these substances, the less viscous the blood and the faster the flow. The diabetic has problem with blood flow due to substance like sugar finding its way into the blood. 

Beside blood content, temperature also affects the viscosity. Just like palm oil when heated (high temperature), it flows faster. This means its viscosity becomes low when temperature is high and vice versa. Same is for blood. At extreme cold weather, blood temperature especially at regions of tiny veins like fingers can get extremely low. Thus, the viscosity of blood during extremely cold weather becomes high. Consequently, blood may not flow or flow insufficiently to that region. Then, health issues arise. This explains why we must cover well during severe cold especially those susceptible areas with gloves.

When flow is low, pressure will increase to keep the blood flow. The extent of low flow is the extent to which the blood pressure increases. When that pressure is extremely high. That is what known as hypertension. 

Engineering Explanation

The study of flow is an engineering field. It starts from the fluid mechanics as general foundation then biorheology as a specialised area of engineering physiology. This field provides the relationship between all these parameters I'd mentioned. It does that through Poiseuille Equation. 

Poiseuille Equation

This equation is perhaps the most important equation offers by engineering for perfect understanding of human anatomy relating to blood flow and heamorheology. It connects  flow rate resistance to flow and pressure  with factors affecting it ( viscosity, vessel *radius and length) to enable us to effectively control it through our meal, manner and monitoring. In fact, Poiseuille equation is for us all.

Flow =constant*(pressure*radius^4) /(viscosity*Length)

Flow =pressure/flow resistance

From the above equation, the length is the only parameters that may not be emphasized because it does not significantly change. However, read following are true:

1. Flow is proportional to radius to the 4th power. When the vessel radius is reduced by half, blood flow is reduced by 16! The pressure get very increased to compensate for it. Hypertension. The heart, the pumping machine works more forcefully. What happens to pumping machine working  forcefully and speed? It breaks down!!! 

How open or close are the vessel radius is the most critical factor in our health. 

a. Take rest

Stress or heavy activity causes compressive forces that stricken the vessels. Learn to take rest. When you take rest, the vessels and veins get relaxed. 

b. Exercise

Exercise leads to tensile forces that cause dilation of these veins and vessels or stretches them out. And with heavy breathing that follows, some opening can be created in the blood passage. Then the flow increases and better. The pressure needs not to arbitrarily  increase. Sneezing is a natural gift for the same purpose improving the flow.

c. Drink warm water

When our kitchen pipes are block with oils, we pour hot water to flush the channel and create more space for flow. Drinking warm water widens the radius of the veins for better flow.

d. Eat less fat

Just as oily, fatty or nylon materials block waterways, eating less of such foods to prevent gradual narrowing of the vascular diameter.

e. Sleeping on the right

The heart, the blood pumping machine, is located close to the left side. Regular sleeping on that side compresses the heart and narrows the channels for better blood flow.

f. Fasting

Self denial to eat less or restrain from eating for sometimes enables some substances to burn off and give way in the blood passage.

2. Flow is indirectly proportional to viscosity. Keep the viscosity of the blood low to increase flow so that the pressure will not have to be abysmally increase. One way to do this is by drinking enough water. Dehydration increases blood viscosity.

Hypertension in Old age:

Explanation: vessels and veins get weaken and become stiffen with old age. Their radius are narrower and flow is impaired. The pressure get increased to to keep flow subjecting the heart into stress and excessive work. 

Hypertension in diabetic patients:

Explanation: diabetes means glucose in blood. It increases blood viscosity. With their inverse relation, flow reduces and  pressure then increases to compensate to keep the flow.

Avoid stress, exercise, drink enough water, take hot drinks more frequently, clothe well for cold season. 

It is worthy to mention that Islamic tradition that asks Muslim to fast weekly and annually , avoid extremely fatty meat like pork, sleep on their right side and thank God when they sneeze is in mutual agreement with nature and science. Islam is truly the fitrah (natural order) upon which man is created.