This study was approved by the Institutional Review Board of Kyushu University. Written informed consent was obtained from all participants before they were enrolled.
Subjects
This study enrolled outpatients with CFS who visited the Department of Psychosomatic Medicine of Kyushu University Hospital. Inclusion criteria were the following: (1) the subject’s fatigue did not improve sufficiently with ordinary treatment given in our Department (as an example see [10]), including pharmacotherapy (for example, antidepressants, Japanese traditional herbal medicine [11],[12], and/or coenzyme Q10), psychotherapy, and/or GET; in some cases, a four-week inpatient treatment program was also included [10]) for at least six months; (2) the subject was between 20 and 70 years old; (3) the subject’s level of fatigue was serious enough to cause an absence from school or the workplace at least several days a month but not serious enough to require assistance with the activities of daily living; (4) the subject was able to fill out the questionnaire without assistance; (5) the subject could sit for at least 30 minutes; and (6) the subject could visit Kyushu University Hospital regularly every two or three weeks. Subjects were excluded if (1) their fatigue was due to a physical disease such as liver, kidney, heart, respiratory, endocrine, autoimmune, or malignant disease, severe anemia, electrolyte abnormalities, obesity, or pregnancy; and (2) they had previously practiced yoga. The diagnosis of CFS was made for patients meeting the diagnostic criteria of the 1994 international research case definition of CFS [1]. Patients with idiopathic chronic fatigue were not included in this study.
Methods
Following enrollment, eligible participants were randomized using a computer-generated randomization list to receive either an isometric yoga practice together with conventional pharmacotherapy group (yoga group, n = 15) or to a conventional pharmacotherapy alone group (wait-list control group, n = 15) for approximately two months. As the patients visited the hospital every two or three weeks, the intervention period lasted 9.2 ± 2.5 (mean ± standard deviation (SD)) weeks after the start of the intervention (Figure 1).
Development of the yoga program
Before starting this trial, we consulted yoga instructors to identify a program that would satisfy the following requirements. Firstly, because patients with CFS have severe fatigue, it should not exacerbate their symptoms or cause post-exertion malaise. Secondly, because the patients are deconditioned, it should also act as an exercise therapy. Thirdly, because the patients’ concentration and short-term memory are impaired, it should be simple and easy to do. Fourthly, because the patients would be treated at the hospital, not at a yoga studio, it must be able to be practiced in an outpatient setting, where space is limited. To satisfy these requirements, we determined that the trial would include isometric yoga, or an isometric yogic breathing exercise, as a treatment for patients with CFS. Isometric yoga, which was developed by Dr. Keishin Kimura, differs from traditional yoga postures in several ways. The predominant difference is that the poses consist mainly of isometric muscle contractions. Since the patients can change resistance depending on their fatigue level, we thought that isometric yoga would help prevent worsened fatigue. These poses do not include isotonic muscular contractions or strong stretching and require less physical flexibility. Therefore, we hypothesized that practicing this form of yoga would be easy on the patients, preventing over-stretching, which is detrimental and may increase pain. However, as are traditional yoga poses, these poses are conducted slowly in accordance with breathing and with awareness of inner sensations. We intentionally avoided standing postures, because a considerable number of CFS patients suffer from orthostatic intolerance, including postural orthostatic tachycardia syndrome [13]. This 20-minute yoga program can be practiced in a sitting position and consists of three parts. First, patients are asked to be aware of their spontaneous breathing for one minute. Next, they practice six poses. These poses are very slow movements that are coordinated with the timing of breathing, with or without sounds, and isometric exercise at 50% of the patient’s maximal physical strength. Lastly, the patients practice abdominal breathing for one minute (Figure 2).
Yoga intervention
Patients in the yoga group practiced isometric yoga in a quiet room for 20 minutes on a one-to-one basis with an instructor who has over 30 years of experience. The sessions occurred between 2 pm and 4 pm on the day they visited the hospital. In this program, the yoga instructor was not allowed to use background music, which is often used in the yoga studio to facilitate the participants’ relaxation, because many patients with CFS are sensitive to sounds. Before and after practicing isometric yoga, the doctors in charge checked the patient’s condition and recorded any adverse events or any changes caused by practicing isometric yoga. In addition to receiving a private lesson, the participants were asked to practice this program on non-class days if they could, with the aid of a digital videodisc and a booklet. Most patients visited their doctor every two to three weeks during the intervention period. Therefore, all patients practiced isometric yoga at least four times (mean ± SD, 5.6 ± 1.7 times) with the instructor during the intervention period. Basically, all patients practiced the same 20-min program, both with an instructor and at home. However, the program was modified on a patient-to-patient basis, in most cases skipping a certain pose or decreasing the number of repetitions of poses, depending on the severity of their fatigue and the pain associated with the pose.
Outcome assessment
To assess the acute effects of isometric yoga, the fatigue (F) and vigor (V) scores of the Profile of Mood States (POMS) questionnaire [14] were assessed immediately before and after the final 20-minute session of isometric yoga with the instructor. To assess the chronic effects of isometric yoga, fatigue was assessed with Chalder’s fatigue scale (FS) [15] before and after the intervention period in the yoga and control groups. Chalder’s FS is a well-validated, self-reported scale that measures the physical and mental symptoms of fatigue. In the yoga group, the assessments were conducted just before practicing yoga. Patients in this group also completed the Medical Outcomes Study Short Form 8, standard version (SF-8™) before and after the intervention period to assess their health-related quality of life (QOL) [16]. Questionnaires were collected by a nurse.
Adverse events and adherence
Adverse events were monitored in two ways. First, at each visit to the hospital, the doctors in charge determined if a subject experienced any uncomfortable symptoms after practicing yoga with the instructor. Second, patients in the yoga group were asked to keep a “yoga diary,” in which they could record the amount of time they practiced and how they felt after practicing yoga. On the day of the visit, before the patient practiced yoga with the instructor, the doctors checked the diary and determined if the patient had had any symptoms of discomfort. After the intervention period, the diary was collected and checked to determine how often the subjects had practiced yoga at home.
Statistical analyses
The data are presented as the mean ± SD. The differences in the outcome measures were tested by two-way, repeated measures, analysis of variance (ANOVA) of the mean scores. Two comparisons were made: one compared the scores of the yoga group to those of the control group; the other compared the scores measured before the intervention to those measured after. The differences in the patients’ POMS, Chalder’s FS, and SF-8 scores measured before and after the intervention were tested by use of a paired-sample t test. Between-group differences in age and in the POMS, Chalder’s FS, and SF-8 scores measured before and after the intervention were tested by use of an independent-sample t test. Two-tailed tests were used. Fisher’s exact probability test was also used when appropriate. Data were analyzed by using SPSS for Windows, V.17.
