Physical exercise over a long term improves cognitive processing and overall symptoms of fibromyalgia, new research from Sweden shows.

The study, “The role of long-term physical exercise on performance and brain activation during the Stroop colour word task in fibromyalgia patients,” was published in the journal Clinical Physiology and Functional Imaging.

A substantial body of literature has shown that fibromyalgia patients present impaired pain inhibition in the central nervous system. Alterations in brain activation and connectivity are also well-known, including in areas modulating both cognition and pain.

These observations led to the theory that the cognitive complaints in chronic pain patients are caused by the dominance of pain processing over resources that are also needed for cognition — this is called the limited resource theory.

The Stroop color word test (SCWT) is widely used to evaluate the ability to process two specific stimuli simultaneously, such as reading words and identifying colors. The test enables the evaluation of changes in cognition, such as in processing speed, selective attention, and the degree of automaticity (unconscious speech comprehension and production). Impairments in all these parameters have been reported in patients with fibromyalgia using the SCWT.

Physical exercise has been shown to decrease pain sensitivity and to improve cognition in healthy subjects. In fibromyalgia patients, physical exercise reduced pain and tenderness, and improved function and well-being. Importantly, acute exercise has been shown to improve SCWT performance.

Now, scientists used the SCWT and brain imaging (functional magnetic resonance imaging) to compare the effects of a 15-week physical exercise protocol in cognition and brain activation of the cerebral cortex (a critical region in the regulation of cognitive processes) in patients with fibromyalgia and healthy controls.

The results revealed that exercise improved fibromyalgia symptoms and health-related quality of life. Furthermore, the team observed an improvement of the speed of cognitive processing, especially in more demanding tasks, and increased activation of the amygdala, a brain area that regulates the response to pain, stress, and exercise, and with known structural and connectivity alterations in fibromyalgia.

“The exercise intervention yielded reduced fibromyalgia symptoms, improved cognitive processing and increased task-related activation of amygdala,” the team concluded. “Our results suggest beneficial effects of physical exercise on cognitive functioning in [fibromyalgia].”