Stress and cancer - what these two have in common?

Connection between stress and illness on the example of cancer and heart disease
Stress causes some kind of body’s response in everyone. Affecting in the short-term it can improve our performance, but in long-term it’s harmful and causes various diseases from cold to cancer, including heart disease, arthritis, asthma, and ulcers. Two of the most serious illness from the list above are cancer and heart disease, so I will focus on the connection between those and stress.
Studies suggest that there may be links between cancer and emotions. Body’s immune system consist of billions of cells that travel through the bloodstream and defend us against bacteria, viruses, and cancer. The field of research called psychoimmunology believes that prolonged stress may lead to lower levels of norepinephrine (neurotransmitters) in the brain and when the organism reacts for stress with helplessness and depression the chances to reject cancer cells maximized and we are more prone to become ill.
Heart diseases are increasing rapidly all around the world because of an unhealthy lifestyle – people exercise less, smoke more and eat worse. There is a wide range of factors that contribute to the formation of a plaque in the walls of the coronary arteries, but according to researches, it’s clear that stress may have a major impact on it. People who are still being under stress and who aren’t able to control it are at a significantly greater risk for heart disease.
Moreover, certain sorts of people have a particular personality, called coronary-prone behavior patterned and it’s Type A. Those people are hard-driving competitive and aggressive, so they continually try to do more in less time. Thereupon many researches indicate a great link between Type A and heart disease.
As we can see, stress has a great impact on us and cause various diseases. Thus we should try to minimize it in our lives and learn to cope with it effectively, which could guarantee better health.