Pilot Study Characterizing Aerobic Exercise in Women With Systemic Lupus Erythematosus (Exercise SLE Pilot).

We propose a single-arm exploratory study to characterize the responses and adaptations to aerobic exercise in women who have mild to moderate systemic lupus erythematosus (SLE) uncomplicated by organ damage that would limit participation. This is a pilot study to provide additional preliminary data to support a future U01 application. Persistent, excessive fatigue is among the three most debilitating symptoms of SLE and is cited by as many as 50% of patients as the single most debilitating symptom. We have observed, in women with mild SLE, significant relationships among deficits in work capacity and oxygen consumption obtained during treadmill exercise and patient reported measures of fatigue severity. Clinically significant functional aerobic impairment was present in these women, suggesting an underlying pathophysiological limitation that restricted cardiorespiratory capacity to well below that expected to occur as a result of normal deconditioning due to a sedentary lifestyle and lack of physical activity. We have also observed prolonged rest to steady state metabolic transition during even submaximal exercise in women with SLE . At peak exercise, muscle oxygenation deficiency was apparent despite normal increases in central circulatory oxygen delivery to the active muscles. Muscle tissue studies in other laboratories have implicated muscle basal lamina thickening as an oxygen diffusion barrier, which could possibly diminish the rate of tissue oxygen uptake and restrict cardiorespiratory capacity. Aerobic exercise training could improve cardiorespiratory capacity in women with SLE and with that improvement precipitate a reduction in their fatigability, particularly if that fatigability is mediated by impaired cardiorespiratory function.

Our research team is uniquely qualified to undertake this research and is one of the few teams possessing the experience and background necessary for contributing to this novel, understudied, yet critical field of rehabilitation research. For example, in addition to Dr. Keyser's studies on cardiorespiratory dysfunction in women with SLE, our team has studied the effects of an intense aerobic exercise-training program in individuals who have pulmonary hypertension (PH) or interstitial lung disease (ILD), two conditions associated with autoimmune diseases such as SLE. In fact, several of the subjects had SLE and the majority had autoimmune diseases of somewhat similar etiology. Our results demonstrated improved cardiorespiratory function and diminished fatigability in these patients, without serious adverse events, following a 10-week regimen of intense aerobic exercise training. Adherence to the protocol was over 90% in both subject subsets and there were no serious adverse events in either of these groups.

Subjects of the proposed research will be between 21 and 80 years of age and living within a reasonable travel distance from the greater Washington D.C. area. Subjects will be recruited from the NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) Intramural Research Program (IRP) Lupus Clinics. All tests and exercise training will be conducted at the NIH Clinical Center. There will be a single treatment condition consisting of 12-weeks of supervised treadmill walking, three times a week, for 30 minutes per session, at an intensity of 70-80% of the subject's heart rate reserve.

The primary outcome measure for our trial will be the time taken to attain the anaerobic threshold, which is a performance marker of fatigability that is unaffected by patient motivation or perception. Secondary outcome variables will include other measures of cardiorespiratory capacity measured during a cardiopulmonary exercise test (CPET) with accompanying pulmonary gas exchange, central circulatory function (including heart function and an optional measures of peripheral blood flow), and muscle oxygenation analyses. A number of questionnaires will also be completed including: Fatigue Severity Scale, Patient Reported Outcomes Measurement Information System (PROMIS). All of these data will be obtained before and after aerobic exercise training.

Study Impact: Aerobic exercise is generally safe, inexpensive, and can easily be made available and accessible to almost everyone. It requires no approval by regulatory agencies and is thus available as a medically prescribed and supervised intervention almost immediately following confirmation of its safety and efficacy. Effective use of aerobic exercise training as a cardiorespiratory, rehabilitative intervention could have a high degree of impact on personal and public health outcomes.