Stress is both a cause of disease and an aggravating factor. Reducing stress can help prevent disease and to help recover from an existing disease. An article appearing in Postgraduate Medicine (January, 1991;89(1):159-164) enumerated the kinds of health problems caused by stress. According to the article, stress is a cause of cardiovascular disease and may even be related to sudden death. It can cause platelet aggregation and thrombus formation. Stress can make the airways in asthmatics hyperreactive. Stress makes the immune system less effective, making the prospect of getting a cold or the flu more likely. Stress has been linked to headaches, inflammatory bowel conditions and endocrine problems.
Stress actually decreases the activity of natural killer cells (a type of white blood cell), according to research appearing in Stress Medicine (1991;7:53-60). The study looked at the effect daily stress had on the natural killer cells in 92 kibbutz residents. Another study looked at the effect on traumatic stress. Research appearing in Psychosomatic Medicine (1997;59:467-476) looked at a total of 159 workers at the crash site and 41 controls were examined within 2 months of the crash and again 6 months after the crash. Subjects were divided according to whether or not they had contact with human remains. Workers exposed to body parts at the actual crash site, and those who were exposed to remains without expecting to be, exhibited more symptoms of stress than workers who saw bodies and body parts at the morgue and those who did not see human remains. The traumatized group had higher natural killer cell activity at the start of the study and at two months. At the end of six months the levels were comparable to the group that was not traumatized.
Stress can make you more susceptible to the common cold. A study appearing in the New England Journal of Medicine (August 29, 1991;325(9):606-612) looked at 394 subjects who were given nasal drops containing one of five respiratory viruses, and another 26 subjects who were given saline nasal drops. The amount of respiratory infections was directly proportional to the amount of psychological stress the individual was under.
Stress can even affect fertility. A study published in the Medical Tribune (December 1, 1994;16) studied 150 couples and found that the stress of a death in the family had a negative effect on the quality of sperm. Stress caused by a divorce or separation also had a negative effect on sperm. Interestingly, stress from work had no effect on sperm.