Prescribing Exercise for Fibromyalgia Patients

Transcription

1 Prescribing Exercise for Fibromyalgia Patients Sharon R. Clark OVERVIEW OF FIBROMYALGIA (FM) Fibromyalgia (FM) is a common rheumatic disorder characterized by diffuse generalized aching and fatigue. Criteria for classifying persons with FM were adopted by the American College of Rheumatology in 1990 [l]. Recent epidemiological studies have shown that FM has a prevalence of 1-3% [2-51 and is the second most common rheumatic condition seen by rheumatologists [6]. The typical patient is a woman with symptoms that began between the ages of 25 and 50 and that have been present for at least 5 years. Although FM is not deforming, many patients consider the pain to be disabling [7,8]. Despite medical intervention, the symptoms tend to be unrelenting, with most patients experiencing little change over a 3-year period. The natural course of FM appears to lead to functional disability and long-term chronic disease [%lo]. Exercise may aid in ameliorating the functional disability, but teaching patients how to exercise properly requires consideration of the probable origin of the pain. Researchers are currently exploring the roles of both peripheral and central pain mechanisms in FM. For example, it is possible that altered muscular activity initiates nociception, which then provides the stimulus for central nervous system amplification of pain perception. Several findings support the notion that a defect in muscular activity is a necessary condition for pain in FM: (1) epidural anesthetics abolish Sharon R. Clark, PhD, FNP, is Associate Professor of Nursing and Assistant Professor of Medicine (Research) at Oregon Health Sciences University, Portland, Oregon. Address correspondence to Sharon R. Clark, PhD, FNP, Oregon Health Sciences University, Portland. OR Submitted for publication March 24,1994; accepted July 28, by the American College of Rheumatology. the pain below the level of the block [TI]; (2) injection of tender point areas with a local anesthetic results in a temporary relief of pain in the region [12]; and (3) overuse of muscle groups causes a flare of pain in that location [13]. The proposed muscle defect appears to be focal, rather than global in nature. Evidence for lack of a global defect is provided by the findings that: (1) FM patients do not have chronically elevated levels of muscle enzymes [14,15]; (2) there are no distinctive findings on routine electromyography (EMG) [IS]; (3) there are no consistent findings on muscle biopsies [17-201; and (4) studies in human performance laboratories have failed to show alterations in oxygen/ carbon dioxide exchange ratios [21,22]. On the other hand, support for a local muscle defect is provided by findings that: (1) FM patients have shown a pattern of maldistribution of oxygen tension consistent with decreased capillary blood flow [23]; and (2) biopsied tender points have shown a reduction in adenosine triphosphate and phosphoryl creatine when compared to normal controls [24]. EXERCISE-INDUCED PAIN The experience of exercise-induced pain reported by FM patients provides additional information for consideration when assisting them to decide upon an exercise program. FM patients often state that their exercise-induced pain seldom occurs during the exercise bout but rather 1,2, or 3 days following exertion. This is similar to the experience that all persons have after performing unaccustomed exercise, which produces muscle microtrauma and subsequent delayedonset muscle soreness. Most persons who experience delayed-onset muscle soreness will overcome this soreness within a few days. However, recovery does /94/$

2 222 Clark Vol. 7, No. 4, December 1994 Aerobic Fitness in 105 FM patients C 1 patients to exercise appropriately. In addition, it is essential to prescribe at the appropriate intensity given patients initial levels of fitness. FITNESS TESTING AND EXERCISE PRESCRIPTION Figure 1. Fitness levels of 105 women with FM compared to American Heart Association established age-sex matched categories [32]. not appear to be easily accomplished by FM patients. Two factors that may play a prominent role in this impaired recovery among many patients are: (1) a deficiency in growth hormone, as shown by low levels of Somatomedin-C [25], which has been implicated in compromising the healing of the microtrauma; and (2) an inability of the muscles to relax in pauses between isokinetic shoulder flexions [26]. With regard to the latter factor, the prolonged EMG firing patterns of the muscles during the pauses are suggestive of sustained eccentric muscle contraction. The absence of reduction of muscle activity related to pain and fatigue may lead to muscle deconditioning, thus increasing the likelihood of microtrauma to the myofibrils when activity is undertaken by the patient [ Given these data, it is reasonable to conclude that conditioning of muscles plays an important role in the management of FM. The notion that endurance exercise has a role in ameliorating the symptoms of FM has been recognized since the early work of Moldofsky and Scarisbrick [30]. Despite this knowledge, many FM patients find it difficult to engage in a fitness program at a level sufficient to achieve a training effect. Part of this difficulty may be due to the approach used by health care providers when prescribing exercise for FM patients. Many of these providers may have inadvertently misguided their patients by failing to recognize that the pain experienced following exercise may be a result of too much eccentric work (contracting and lengthening a muscle) and/or working at too high an intensity. Teaching the nature of eccentric work and initially prescribing stretching followed by activities that minimize eccentric workload will help At Oregon Health Sciences University we measure the endurance fitness level of all participants in an FM treatment program in a human performance laboratory utilizing a metabolic cart. While performing a modified Balke treadmill test, breath-to-breath analysis of oxygen consumption and carbon dioxide production, heart rate, workload, minutes of exercise, and rate of perceived exertion (RPE) [31] are monitored. When testing in a performance laboratory is not available, endurance capacity is evaluated by measuring the distance walked in a 6-minute walk test [32]. Comparisons of our patients fitness levels with published values from the American Heart Association [33] support the notion that FM patients are deconditioned. We have found that 64% of 105 FM patients so tested were below average when compared to other women their age (Figure 1). Sixty-four percent of the same patients reported that they did not engage in any form of regular exercise. The level of fitness of FM patients can be improved with a properly prescribed endurance training program that does not exacerbate a flare in symptoms [34,35]. Proper prescription is the key element. Although there appears to be no known contraindication to any endurance activities, clinical experience supports the conclusion that walking and water activities utilizing an aqua jogger are best tolerated. Those who do not experience gluteal myofascial trigger points can tolerate cycling. There are others, however, who find that while cycling they develop symptoms similar to those produced by sciatic nerve involvement. Unfortunately they are often subjected to very extensive workups for back problems when the problem is myofascia1 and should be treated as such. It also has been observed that FM patients do not tolerate the low impact aerobic classes that rely on upper body work in order to keep the heart rate within the target range, nor do they tolerate the eccentric contractions required during weight training. APPLICATION OF EXERCISE PRESCRIPTION: CASE STUDY The following case study is provided in order to demonstrate how an exercise prescription might be

3 Arthritis Care and Research Exercise for Fibromyalgia Patients 223 utilized successfully by an FM patient following the guidelines shown in Table 1. This method of prescribing has resulted in significant improvement in flexibility and endurance in 105 FM patients evaluated at our center [36]. CASE EXAMPLE A 45-year-old woman, who was diagnosed with FM, came in with the following complaint: I ache all over such that I feel as if I have been run over by a Mack truck. I wake up in the morning feeling as tired as when I go to bed at night, even if I slept through the entire night. These symptoms have been present for 7 years and evaluated by multiple physicians, including a psychiatrist, in an attempt to obtain relief. Treatment has included nonsteroidal anti-inflammatory and analgesic medications, tranquilizers, and even oral corticosteroids with little to no relief. The patient s exercise history reveals that she is a sedentary woman who has not performed any regular exercise for the past 6 years. She complains that she feels very tired after exercising and notes that this fatigue may last more than 24 hours. She also notes an increase in pain, particularly 2-3 days after an exercise bout. She is evaluated using a 6-minute walk test and is found to have low endurance capacity. At the conclusion of the walk, she complains of leg pain and fatigue. Although she has not used it for several months, she does have a stationary bicycle at home and believes that she could ride the cycle for a few minutes each day. She is taught a stretching program and does repeat demonstrations, appropriately performing the stretches. After 3 weeks she complains that every time she has an exercise bout, she develops a headache. Examination reveals a trigger point that reproduces the headache. These trigger points are very common and may interfere with continuing activity. It is important that they be recognized as trigger points that may respond to therapy with stretching and injections if necessary. When her trigger point is treated, she obtains relief and is able to continue with her exercise training. After exercising 5 minutes daily on the cycle for 5 weeks, she finds that she begins to develop buttock and leg pain and wishes for an alternate exercise regimen. She is instructed to alternate cycling with walking and is able to manage this. At the end of 6 weeks she is exercising at 60% of her maximum heart rate and is able to exercise for 20 minutes in one bout. She does not feel, however, that she is able to increase either the intensity or the duration of exercise; therefore, additional sessions are added to her training program. At 20 minutes of exercise at 60% of her maxi- TABLE 1 Exercise Prescription for FM Patients Phase Instructions Rationale I Comprehensive Stretch only to Golgi tendon appastretching the point of re- ratus to increase sistance, not in- relaxation [37] creased pain I1 Endurance Start low, build Maintaining intensigradually, and ty between 60 and calculate train- 70% maximum 111 Strength ing index [TIP Assure muscles heart rate; minimum TI of 42 recommended to achieve health-related benefits 1391 Eccentric work is are warmed: utilize range of primary in microtrauma [40] motion that minimizes eccentric work TI: The product of intensity (percent maximum heart rate) x deviation (rninutes/session) x frequency (number of exercise sessiondweek); adapted from Hagberg 138). mum heart rate, her training index (TI) for each session is 12. Thus, if she performs at least four exercise bouts in a given week her TI will exceed the recommended minimum level of 42. The daily exercise bouts may be divided, e.g., 15 minutes may be performed in one 15-minute session, or an 8-minute session and a second 7-minute session, or in three 5-minute sessions. In this manner, greater flexibility to accomplish the weekly goal of a TI between 42 and 90 can be achieved. Differentiating the myofascial trigger point pain from her generalized FM pain and appropriately treating the trigger point allowed her to continue to exercise without experiencing enhanced pain. CONCLUSIONS Regardless of the presence or absence of FM, maintaining an endurance exercise program is difficult. The increased pain and fatigue frequently encountered in the beginning stages of exercise often is a result of working at too high an intensity level. Thus it is necessary to determine the combination of the intensity, duration, and frequency that will be best tolerated by the patient. The intensity should be between 60 and 70% of the maximum heart rate; the duration and frequency may then be individually adjusted in order to achieve a TI of at least 42.

4 224 Clark Vol. 7, No. 4, December 1994 It is also important to recognize that regardless of whether peripheral or central mechanisms account for the pain of FM, the pain is real and needs to be considered when prescribing exercise. In order to minimize this pain, one should start with a gentle exercise program and then add endurance training. Recommend that when an exercise bout is completed, there should be a feeling that I could have done more rather than a feeling that I have done all that I can. It is important to note that exercise can be done without experiencing an increase in pain if the principles of reducing the amount of eccentric work and working at lower intensity levels are followed. Following these guidelines will minimize the muscle microtrauma and decrease the transmission of nociceptive stimuli to the central nervous system. REFERENCES 1. 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