It would be nice to have a clear and straightforward answer. However the factors to get sick are so many! Still, people have been on this planet for a while and they have come up with some good explanations
Let me first go through the conventional causes which will be more close to most of us. Most diseases manifest because of two main reasons
Pretty amazing! A coil of DNA encodes safely the rules for the development of trillions of cells as a single organism. Starting from the color of your skin, the shape of your body and ending with the strength of your internal organs it all depends to a big extent on genes.
Unfortunately evolution has not made the DNA encodings perfect yet. Therefore when humans are under the influence of specific environmental conditions, certain genes become the underlying reason for disease manifestation. For instance recent studies show that myopia has become so pervasive in the last one hundred years as a result of the big exposure to close work. It would be much less likely for the same population to develop myopia in the coal age.
The vital status and potential of human internal organs is also dependent on the innate energy inherited from the parents. A perfectly balanced and strong system of internal organs is a prerequisite for longevity and happy life.
So, I would definitely classify genetics as the factor number one defining your susceptibility to get sick.
I would give anything to get exterminated any virus or bacteria, however, they are part of our world and there is little we can do about it. And even worse: We are food for them! Which immediately makes them our enemies. The weaker we are, the more welcome they feel to come and party within our bodies.
Viruses and bacteria cause the so called infectious diseases. They are transmitted from one individual to another most often via a medium such as air, food, water, saliva or other body liquids.
The good news is that humans have been designed with an immune system, which is the system to take care of intruders. External pathogens such as viruses and bacteria are attacked by the immune system and, if it is strong enough, the internal balance of the healthy physical body restored. You may even not notice the presence of a virus.
The status of the immune system depends on various factors. The most important one is surprise, surprise Genetics! Next come your exposure to various challengers, i.e. the more you expose your immune system to external pathogens the stronger it becomes. Last but not least the strength of your immune system will depend on a magical mixture of vitamins and minerals necessary for its agility and responsiveness to the pathogens.
The bad news is that viruses and bacteria constantly evolve and quite often the immune system of the ordinary human is caught off guard.
We have discussed so far that genetics and the immune system strength are the two most important factors defining your susceptibility to illness. This is well accepted explanation by the contemporary Western mind.
However, they are factors, i.e. driving force. Whether or not this driving force will manifest as a condition depends on their combination with various additional environmental and social variables. The result of the simultaneous application of all factors on an individual, which at the end is the root cause of any manifested illness, has been understood thousands of years ago and has been called disharmony at the level of blood and energy.
For instance if you have inherited a weak internal organ, then its functioning would not be synced with all other organs and this would cause a disharmony at the level of blood and energy which at a later stage would manifest as an illness.
Most diseases take place due to stagnation of blood and energy in the human body.
A healthy human has good quality blood and energy in abundance circulating without obstructions in the body. Healthy blood is liquid, red and has no specific odor.
Stagnant energy and blood can be due to many different causes, the most common of which are sedentary lifestyle, stress, strong emotional shock, bad genes or inadequately treated and unresolved infection. A weak internal organ may be the reason for weak energy flow and therefore for disharmonies causing stagnation and blockages.
According to traditional Chinese medicine human blood and internal energy, called in Chinese qi, are closely related. Simply put, if the energy is not moving, the blood also stagnates and vice versa if the blood does not circulate freely in the human body, qi stagnates.
With the passage of time the blood tissue becomes thicker at the affected area. This is the first phase of imbalance, according to traditional Chinese medicine and it is diagnosed as a mild blockage of the circulation of qi in the affected meridians. The methods of Western medicine even nowadays are unable to find a problem in a similar condition of the patient.
If the blockage is not removed in due time, these condensations of blood tissue get dehydrated over time and transform into entities like clots, which lead to more serious blockages of the blood circulation in the affected tissues and organs. Accumulated clots gradually change color, first become yellow, then brown and finally black. Note that at this stage, the clots are present in the tissue, wherein the capillaries deliver nutrients to the cells, thus affecting metabolism quality. This is the second phase of imbalance, according to traditional Chinese medicine.
At this stage most clots are present in the vital organs capillaries. It is possible to generate heat because the body treats the situation as external attack, but this autoimmune reaction, which in most cases is effective against external pathogens such as viruses or parasites, does not lead to an effective solution of the problem. Not only it does not help, but this normal response of the body leads to speeding up the process of condensation and intoxication in the affected areas. This way gradually appear toxins typical for third phase blockages which are characterized by a large amount of pathogenic heat in the blocked meridians.
Phases four and five are characterized by qualitative changes in blood clots that acquire specific, pungent smell and texture. The cells at the affected area die due to the lack of nutrients and oxygen and very often appear as white particles if extracted for diagnosis. After phase three western medicine may signal any deviation from norms based on blood analysis, but is unable to give an accurate diagnosis of the root cause.
It should be noted that while conditions of phases 1 and 2 have a chance of successful treatment with acupuncture or herbs, phases 3, 4 and 5 may not be affected in a similar way because of the extremely serious state of the blockages. Even western medicine suffers serious setbacks in the long run with such conditions as doctors focus on eliminating the effects of the disease and not the causes for it. Very often the causes of the disease remain unknown and the doctors, in their powerlessness to help effectively, create vicious schemes to consume financial resources of patients, while temporarily relieving symptoms or, even worse, further deteriorating their health.
If the blockages of blood and energy circulation remain untreated, the normal functions of the internal organs are severely affected. Thus, seemingly from nowhere, especially for people for whom prophylactic examinations are taboo, manifest serious diseases such as cirrhosis, diabetes, cancer, hormonal disorders.