Stress is both a contributor to disease and a factor that can worsen existing health problems. Reducing stress may help lower disease risk and support recovery. An article published in Postgraduate Medicine (January 1991; Volume 89, Issue 1, Pages 159–164) outlined a wide range of health effects associated with stress. According to the authors, stress contributes to cardiovascular disease and may be linked to sudden death. It has been associated with increased platelet aggregation and thrombus formation, heightened airway reactivity in individuals with asthma, reduced immune effectiveness, and a higher likelihood of infections such as colds and influenza. Stress has also been linked to headaches, inflammatory bowel conditions, and endocrine disturbances.
Stress has measurable effects on immune function. Research published in Stress Medicine (1991; Volume 7, Pages 53–60) found that daily stress reduced the activity of natural killer (NK) cells, an important component of immune defense. This study examined 92 residents of a kibbutz and demonstrated that ongoing stress was associated with suppressed NK cell activity.
Other research has examined the immune effects of traumatic stress. A study published in Psychosomatic Medicine (1997; Volume 59, Pages 467–476) evaluated 159 workers at a crash site and 41 control subjects. Participants were assessed within two months of the crash and again six months later. Workers were grouped based on exposure to human remains. Those unexpectedly exposed to body parts at the crash site exhibited more stress symptoms than those who viewed remains in a morgue setting or had no exposure. The traumatized group showed higher NK cell activity initially and at two months, with levels returning to those of non-traumatized controls by six months.
Stress has also been shown to increase susceptibility to respiratory infections. A study published in New England Journal of Medicine (August 29, 1991; Volume 325, Issue 9, Pages 606–612) exposed 394 participants to nasal drops containing one of five respiratory viruses and 26 participants to saline drops. The likelihood of developing an infection increased in direct proportion to the level of psychological stress reported by the participants.
Reproductive health may also be affected by stress. A study reported in Medical Tribune (December 1, 1994; Volume 16) examined 150 couples and found that major life stressors, such as the death of a family member, were associated with reduced sperm quality. Stress related to divorce or separation showed similar effects, whereas work-related stress did not appear to influence sperm parameters.
