Randomised controlled trials that compared any form of active exercise within a warm water environment (hydrotherapy) with any control group in patients of any age and gender with fibromyalgia were eligible for inclusion if they reported on pain/tenderness, quality of life or functional outcome measures. Fibromyalgia had to be diagnosed by American College of Rheumatology criteria. Only trials that reported significant outcomes were included in the review.
All trials included a warm up, cool down or relaxation period in their hydrotherapy programme, all included some form of aerobic exercise and all used a group hydrotherapy program. Half of the trials used an education or land-based exercise cointervention. Control groups were no treatment, home or land-based exercise and exercises in the sea or a pool. Sessions lasted for between 30 and 60 minutes, one to four times a week for between four and 32 weeks.
Studies were selected by two reviewers.