Fibromyalgia is becoming a common syndrome in Western European countries since a point prevalence of 2.9% would translate to approximately 6 million people with fibromyalgia [1
]. The prevalence of fibromyalgia in Spain is ~2.4%, and is more common in women (~4.2%) than in men (~0.2%) [2
Fibromyalgia is considered a disorder of pain regulation [3
], as indicated by an increased sensitivity to painful stimuli (hyperalgesia) and lowered pain threshold (allodynia) [4
]. Additionally to pain, fibromyalgia symptoms typically include fatigue, stiffness, non-restorative sleep patterns, and memory and cognitive difficulties [5
]. Other common symptoms are low back pain, recurrent headaches, muscle-spasm, and balance problems [5
]. The prevalence of comorbidities among patients diagnosed with fibromyalgia is very high [8
], which increases patients' needs for appropriate medical management and results in higher healthcare resource utilization compared with persons without fibromyalgia [9
Fibromyalgia has an important impact on the patients' health-related quality of life [10
], since it limits activities of daily life such as walking or raising and transporting objects [11
]. In general, functional capacity is decreased in adults with fibromyalgia [13
] and is similar to that of healthy elderly [16
]. Jones et al. [19
] reported that women with fibromyalgia have difficulties for staying physically independent.
Exercise therapy is relatively economical, easily accessible and widely used in clinical practice as a strategy for pain management. Several reviews concerning the effect of exercise in fibromyalgia patients concluded that: i) there is moderate evidence that aerobic exercise produces important benefits in physical function, pain and tender points [20
]; ii) there is limited evidence that strength training improves pain, global wellbeing, physical function, tender points and depression [22
]; and iii) there is not enough evidence regarding the health-related effects of flexibility exercises [22
]. A recent meta-analysis [23
] concluded that exercise (aerobic, strength training or both) improves global well-being, assessed by the fibromyalgia impact questionnaire (FIQ) in women with fibromyalgia. The Ottawa Panel supports the use of aerobic exercise interventions and strengthening exercises for the overall management of fibromyalgia [24
Exercise therapy in fibromyalgia patients has usually focused on either pool or land-based exercises. A recent meta-analysis [26
] indicated that there is no evidence that water-based aerobic exercise produces superior results compared to similarly intense land-based exercise. Others narrative reviews however suggested slight additional benefits for water-based aerobic exercise on reducing pain and improving depressive symptoms [27
], sleep quality and mood [20
]. Jentoff et al. [28
] compared the effect of a 20-week pool-based exercise and a land-based exercise intervention (twice a week) on symptoms, self-efficacy, self-reported physical impairment, and physical capacity in a group of fibromyalgia patients. They observed significant improvements in cardiovascular capacity and walking time in both exercise groups. The pool-exercise group also improved self-reported physical impairment, number of days feeling good, pain, anxiety, and depression. To our knowledge, the study by Jentoff et al. [28
] is the only available study investigating the possible additional beneficial effects of exercising in a warm-water pool (compared to land-based) in fibromyalgia patients. More studies comparing the effectives of a water-based exercise program with a land-based exercise intervention on a broader range of physical and psychological outcomes and with longer intervention period, higher frequency, and larger samples are needed.
It is of public health and clinical relevance to better understand whether the benefits of land-based exercise are similar to those observed with exercise undertaken in water, owing to the low availability of pools with an appropriate water temperature for these patients, ideally between 30 and 33°C.
The primary objective of the al-Andalus physical activity randomised controlled trial (RCT) is to investigate the effectiveness of two types of exercise interventions (water- and land-based aerobic-strength training vs. a control group) on the overall impact of fibromyalgia (primary outcome), and on tenderness and pain-related measures, body composition, functional capacity, physical activity and sedentary behaviour, fatigue, sleep quality, health-related quality of life and cognitive function (secondary outcomes) in women aged 35-65 years with fibromyalgia. The intervention groups will train 3 days/week (60 min per session) for a 24-week period. We will also study the effect of a detraining period (i.e., 12 weeks with no exercise intervention) on the studied variables.