Background: Patients with fibromyalgia (FM) often reports that cognitive function have declined (i.e. 1,2). Consistent with these complaints, several studies have revealed poor working, impaired long-term memory, vocabulary deficits and lower or intact information processing speed (i.e. 3, 4).
Exist a large quantity of studies that suggest the positive effect of moderated physical exercise in the cognitive function of several healthy (5) and clinical populations (6).
Although the number of studies examining the benefit of exercise for FM has steadily increased in the last 20 years, no study has addressed the benefits of exercise alone in the cognitive function. To date, only 2 studies on treatment and FM that have controlled the cognitive function have been published (7, 8). Both studies improved cognitive function in FM patients, but they were multidisciplinary, including aquatic exercise and education, and therefore we can not discern if the effects were due to exercise, to the education or to both.

Objectives: To evaluate the short-term efficacy of exercise therapy in a warm, chest-high pool on pain and cognitive function in women with FM.
Methods: Sixty middle-aged women with FM were randomly assigned to either an exercise training group (n = 35, age 50 ± 7 years) to perform 3 weekly sessions of aquatic training (32ºC) including aerobic, mobility, strengthening, and relaxation exercises during 16 weeks, or a control group (n = 25, age 46 ± 8 years). Pain threshold was assessed using a syringe calibrated like pressure dolorimeter (9), and cognitive function was assessed using a large battery of standardized neuropsychological test: Repetition of digits and reversal of digits tests (10), Paced Auditory Serial Addition Task (11), Rey Auditory Verbal Learning Test (12) and Controlled Oral Word Association Test (10). All participants were measured at baseline and post-treatment.

Results: The exercise group improved significantly pain threshold (p < 0.001), tender point count (p < 0.001), and cognitive function in all of the neuropsychological test (p < 0.01), while than in the control group the differences were not significant.

Conclusion: An exercise therapy three times per week for 16 weeks in a chest-high pool of warm water is an adequate treatment to decrease the pain and to improve cognitive function in previously unfit women with FM.
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