Fibromyalgia (FM) is a complex clinical syndrome characterized by chronic widespread musculoskeletal pain, sleep disturbances, morning stiffness, fatigue, anxiety, and depressive symptoms. Its etiology is not known, and several aspects of its pathogenesis are being investigated, shedding some light on the possible physiopathologic mechanisms involved in this process.

It has been hypothesized that FM is a disease of the mechanisms related to pain processing both at a central level (1) and at the peripheral level (2). This would result in a generalized situation of hyperalgesia. Several neurohormonal alterations have been described in these patients that could justify the pain and explain part of this hypothesis (3).

The presence of widespread pain in muscular areas, muscular weakness, fatigue, and stiffness reported by these patients suggests that there could exist an underlying muscle pathology, or at least a pathogenic mechanism in which muscles play an important role. Indeed, morphologic and functional studies carried out on muscles and tender points have shown a series of structural biochemical and functional alterations, which are not exclusive to FM and can be observed in other processes (4).

One of the most commonly observed functional alterations in these patients is their poor physical fitness, characterized by a lesser capacity to perform physical exercise and an increasing tendency to fatigue on usual activities (5). What remains to be determined is whether this poor physical fitness is produced by the lack of physical activity observed in these patients or whether it is resulting from an illness of the musculoskeletal system. In any case, it has been shown that both aerobic capacity and muscular strength can improve after programs of physical training without any harm to the patient (6, 7).

In FM treatment, analgesics, antiinflammatory drugs, muscle relaxants, and antidepressants have been used. Most clinical trials with drugs, although useful to improve clinical symptoms in these patients, have been carried out for short periods of time (8). Because FM is a problem of chronic pain, the results of any treatment should be evaluated in the long term. There are no followup studies of drug treatments that allow us to value their usefulness for extended periods of time. On the other hand, the followup studies of patients with FM show that patients very often abandon medication because the symptoms do not change despite long-term treatment (9, 10).

Recently, several nonpharmacologic treatments have been tried in patients with FM. In fact, since the seminal work of McCain et al (11), which showed an improvement in the symptoms of the FM patients treated with physical exercise (PE), several clinical trials have been published confirming the beneficial effects of several types of PE-based treatments (12–17). However, followup studies in these patients have shown that clinical benefits do not persist (13). One possible explanation of these findings may be the loss of physical fitness, which precludes drawing conclusions about the long-term effect of good physical fitness in clinical manifestations of FM patients.

Treatments with learning techniques designed to improve several cognitive and behavioral aspects of the internal control of reactivity in situations of chronic pain (cognitive-behavioral therapy [CBT]) have proved useful in the treatment of FM (13, 18) and other rheumatic diseases (19, 20). Although the need for focusing on the maintenance of treatment gains generated by CBT interventions has been previously described in rheumatoid arthritis patients (20), most of the clinical trials in FM patients have only been carried out during short periods of time and the final evaluation of the results has been performed immediately after finishing the treatment.

In the short term, treating FM with only CBT has proved less efficient than treating with PE (21). However, treatments that combine several types of CBT and PE have achieved better results (18, 22–25). The goal of this article is to analyze the long-term efficacy of 1 type of CBT and of a PE-based strategy in patients with FM.

The results of this study show that the clinical manifestations of FM improve in the short term both with the application of a CBT treatment and with a treatment based on improving the aerobic capacity and physical fitness of these patients. A substantial number of the items of the FIQ, as well as its total score, showed a favorable evolution in both groups after an 8-week treatment period, indicating an improvement of the clinical manifestations, an improvement in their physical capacity, and a smaller impact on the daily life of the patients. These findings are similar to those of other investigators using treatment protocols similar to ours in short-term studies (12–14, 16, 17).

We also confirmed that pain had been reduced immediately after treatment in some patients. This suggests that the treatments used improved the most important clinical manifestations of FM patients, and not only patients' functional capacity. Usually, pain intensity is one of the symptoms that varies less in clinical trials in FM patients, although there exists an improvement in the rest of the clinical parameters and in functional capacity.

Our results also confirm the capacity of the FIQ to measure changes, as previously proposed (28), which makes this questionnaire one of the most useful instruments in the clinical investigation of patients with FM.

The variables that measure physical fitness and capacity to perform aerobic exercise only improved in those patients of the PE group but not in the CBT group. This shows that the physical training program of our study was successful in reaching the aims of improving the functional capacity of these patients. Previously it has been shown that patients with FM, in spite of their poor physical fitness, are able to perform a physical training directed at increasing their muscle strength and their aerobic capacity without any harm to the patient (6, 7).

However, the improvement in the functional capacity of patients with FM does not always occur together with an improvement in their clinical manifestations. There are some studies that show an improvement of physical fitness in these patients after the treatment, but without an improvement in their clinical manifestations (11, 39). By contrast, there are other studies where the clinical manifestations of FM improved without an improvement of the physical fitness of the patients (12, 15).

These data suggest that the improvement of the clinical manifestations of our patients might not be related to the physical training program. More specifically, PE improved physical fitness but not necessarily the clinical manifestations of patients with FM.

Assessing physical fitness in patients with FM is difficult because different questionnaires and physical measures are used by many investigators. To our knowledge, there is no agreement concerning which measures of physical fitness are most suitable in FM patients. The same measure of aerobic exercise capacity used in this study has already been used by other investigators (13, 16, 38) with positive results measuring changes. The evaluation of physical activity has not been used before in any study, although we daily perform this evaluation on the patients of our Physical Therapy Unit.

Likewise, patients on the CBT program showed improvement in their clinical symptoms immediately after finishing the treatment program. CBT has also shown a capacity to improve the clinical condition of patients with FM through the improvement in the parameters of self efficacy and learning of specific techniques to cope with chronic pain (21). In this group of patients, however, there was not a considerable improvement in the self-efficacy and coping with chronic pain scores. Also, there was no significant difference with the PE group that could explain the improvement in the CBT group through these mechanisms.

Another possible explanation for the clinical improvement in our patients of both groups is the beneficial effect of the intervention. It is well known that belonging to any therapeutic group for a certain period of time may improve the patient's condition. Mood is known to improve with physical exercise (17) and, apparently, the improvement of mood depends on the duration of the treatment program: the longer the treatment, the better results (42).

One of the most relevant findings in our study is that we could check how the beneficial effect of the treatment disappeared as time went by, so that at the end of the study, 1 year from the end of the treatment, there was no clinical variable that showed a significant improvement with respect to the initial evaluation. However, physical fitness in the PE group was better than that found at the initial evaluation (see Figure 1). This finding suggests that the improvement in the physical fitness of patients with FM does not necessarily correlate with an improvement in the clinical manifestations of the disease.

There are few controlled studies in which physical treatment, after producing an initial improvement in the clinical manifestations of FM patients, is assessed in the long-term. Wigers et al (13), after obtaining favorable results of an intervention based on a 12-week exercise program, found that there was neither improvement in the clinical variables nor in the physical fitness of these patients 4 years later. Something similar occurs in the work of Jentoft et al (16), during a 46-week followup period. Our study is, to our knowledge, the first one to show that, in spite of the improvement in the physical fitness of patients with FM 1 year after finishing the treatment program, there was no parallel improvement in the clinical manifestations of FM.

Although the patients in the PE group were in better physical condition after 1 year than in the initial evaluation, the beneficial affect was not caused by the initial exercise treatment program. If patients had not kept doing the exercises learned during the program, the beneficial effect would have disappeared. We, therefore, wonder about the benefits of exercises in this group of patients, given the fact that there was no improvement in the clinical manifestations of the disease. There are many alternative explanations.

In the first place, the loss of physical fitness is progressive in the natural history of FM and is related to the time of evolution of the disease (5). Although the patients do not improve in their clinical manifestations, they are aware that PE gives them a higher functional capacity for daily living activities, avoiding new problems with the clinical manifestations of FM.

In the second place, the performance of PE can also be beneficial because PE improves other aspects of the patient's health. For example, low mood (17), depressive symptoms (42), and anxiety (43), which are frequent in patients with FM, are known to improve with PE. In our study, we could not demonstrate these later aspects, as no significant differences were found in the questionnaires used to measure the variables of depression and anxiety after the intervention, and no specific questionnaire was used to assess mood in our patients. In addition, the scores for anxiety or depression in our patients were not excessively high, which indicates a moderate to low intensity of both symptoms. Questionnaires often better measure the changes produced when scores move in the middle ranges.

Quality of life was measured in our study by the self-administered SF-36. The scores obtained were low in almost all dimensions, indicating a poor quality of life, a result similar to that obtained in other studies (25). The SF-36 questionnaire has been developed to measure quality of life in a generic way and there are no data about its responsiveness to perceived clinical changes in patients with FM. Recently, some investigators have shown there were significant differences in some dimensions after 6 months of treatment with combined exercise and CBT therapy (25).

Physical exercise and CBT treatments have previously demonstrated to be superior to controls in improving clinical manifestations in FM patients. Moreover, nonpharmacologic treatments are more efficacious than pharmacologic ones (8). In this study, a control group was not included because the main objective was to check the efficacy of these 2 nonpharmacologic treatment modalities.

Studies of long-term interventions are needed to establish correlations between clinical manifestations and physical fitness improvements in FM patients. Exercise should be done on a daily basis to obtain significant improvements. In CBT long-term interventions, a strategy for maintaining treatment gains should be used (20). Combined CBT and exercise interventions should also be explored in long-term interventions.

In summary, we have found short-term improvement in clinical manifestations of patients with FM with both treatment regimens. In the CBT group, contrary to expectations, this improvement was not associated with a significant change in the variables that measure self efficacy. This suggests that these aspects were not related to clinical improvement. In the PE group, an improvement in the variables that measured physical fitness was found after the treatment, and this improvement lasted the duration of the patients' followup. However, the improvement of the clinical manifestations could only be confirmed right after the conclusion of the intervention, but not 1 year after it. This result suggests that improvement in physical fitness is not necessarily associated with improvement in the clinical manifestations of FM.