Brief dose of stress can do you good, say researchers

STRESS is not always bad for you, a study claims.

A brief dose of stress might actually be healthy as it strengthens the body’s defences, say researchers.

But long-lasting stress can do serious damage by wearing out the immune system.

The most dangerous stressful situations force people to restructure their identities or social roles, and have no clear end-point, the study found.

Examples include living with permanent disabilities from injuries or disease, caring for a spouse with severe dementia and being a war refugee.

The longer that stress persists, the more the immune system is hit by potentially damaging changes, the findings show. First the defences of individual cells are broken down, and then the broader immune function.

The trend emerged from a detailed analysis of pooled data from 293 separate scientific journal studies involving almost 19,000 participants.

Doctors and scientists have long known that stress affects the body’s ability to fight infection. This was strongly confirmed by the new study. But the most striking discovery by the American and Canadian researchers was the emerging pattern of changes.

The findings were published in the American Psychological Association journal Psychological Bulletin.

Dr Suzanne Segerstorm, from the University of Kentucky in Lexington, and Dr Gregory Miller, from the University of British Columbia in Vancouver, wrote: “Stressors with the temporal parameters of the fight-or-flight situations faced by humans’ evolutionary ancestors elicited potentially beneficial changes in the immune system.

“The more a stressor deviated from those parameters by becoming more chronic, however, the more components of the immune system were affected in a potentially detrimental way.”

The two scientists sorted stress-triggers into a number of different categories.

They included “acute time-limited stressors”, such as public speaking, “brief naturalistic stressors” such as academic tests, and “stressful event sequences” caused by focal events such as the loss of a spouse or experiencing a natural disaster.

Stress of this kind is accompanied by the comforting knowledge that at some point it will end.

But the same is not true for “chronic stressors” that makes pervasive demands on individuals. When a person’s world is “turned upside down” by such challenges it has the greatest psychological and physiological impact, the study found. “Distant stressors” can also have long-term effects. These are traumatic experiences that occurred in the distant past yet continue to have lasting emotional and mental consequences. The evidence shows short-term stress “revs up” the immune system to prepare the body for injury or infection.