'Fight or flight' biological response may contribute to fatigue
Newswise, May 25, 2016-- Chronic fatigue syndrome patients report they are more anxious and distressed than people who don’t have the condition, and they are also more likely to suppress those emotions.
In addition, when under stress, they show greater activation of the biological ”fight or flight” mechanism, which may add to their fatigue, according to new research published by the American Psychological Association.
“We hope that this research will contribute to a greater understanding of the needs of people with chronic fatigue syndrome, some of whom may tend not to communicate their experiences of symptoms or stress to other people,” said the study’s lead author, Katharine Rimes, PhD, of King’s College London.
“Others may be unaware of the difficulties experienced by chronic fatigue syndrome patients and therefore not provide appropriate support.”
Participants who felt that expressing their emotions was socially unacceptable were more likely to suppress them. This was the case for both chronic fatigue patients and healthy people, according to the study published in the APA journal Health Psychology.
This study of 160 people in the U.K. relied on self and observer reports, as well as physiological responses that were collected before, during or after the participants watched a distressing film clip. Half of the participants had been diagnosed with chronic fatigue syndrome while the rest were healthy.
Half of each group were instructed to suppress their emotions and half were told to express their feelings as they wished.
Their reactions were filmed and rated by independent observers. Skin conductance was measured because this increases with greater sweating, which is a sign of activation of the body’s sympathetic nervous system. This is often known as the biological fight or flight system used to cope with stress.
Regardless of the instruction they received, the chronic fatigue syndrome participants reported higher anxiety and sadness, and their skin responses indicated they were more distressed than the healthy control group, both before and after the film.
However, those emotions in the chronic fatigue group were less likely to be picked up by the independent observers.
Greater activation of the fight or flight system was associated with greater increases in fatigue in the people with chronic fatigue syndrome, but not among healthy people.
“Patients with chronic fatigue syndrome often tell us that stress worsens their symptoms, but this study demonstrates a possible biological mechanism underlying this effect,” said Rimes.
The authors note that this study was conducted with mainly white patients who were attending a special clinic for chronic fatigue syndrome patients and that more research is needed to determine whether elevated emotional suppression would also be found in chronic fatigue patients in more diverse populations.
Since this study was conducted among people who had already been diagnosed with chronic fatigue syndrome, this does not indicate a causal link between emotional suppression and the syndrome itself, Rimes added.
“These findings may help us understand why some chronic fatigue syndrome patients don’t seek out social support at times of stress,” said Rimes.