Aerobic Exercise for Fatigue in Multiple Sclerosis

September 1999; Volume 2: 104-106

By V. Jane Kattapong, MD, MPH, MA

Multiple sclerosis (ms), a frightening chronic degenerative disease first described by the French neurologist Charcot, largely affects young adults. Typically, the onset occurs between ages 30 and 50.1 Fatigue is one of the most common symptoms of MS. One MS specialist reports that his patients "often say they could manage the problems and symptoms that MS brings if they just were not so fatigued and had more energy."2 The triple, energy-draining whammy of career, family, and MS can be devastating. Therefore, MS patients may benefit greatly from fatigue-relieving therapy.

Course and Therapy

MS is characterized by recurrent attacks or chronic progression of disability. Disability results not only from neurological deficits, but also from other symptoms associated with MS, including fatigue, depression, and a decrease in self-rated quality of life. As a result, the ability to perform daily activities is even more impaired than neurologic deficits would predict.3

Since there is such disability and no pharmacological "cure" for MS, many patients seek alternative therapies. One survey of MS patients determined that physical therapy is the most common non-pharmacological, "alternative" therapy obtained.4 Similarly, primary care practitioners feel acceptance toward exercise counseling as a "legitimate" medical therapy.5 Despite this acceptance, the prevalence of physician-based exercise counseling, in general, is low,6 and it is likely that the prevalence of physician-based exercise counseling for MS patients is even lower than that of the general population.


In MS, multifocal inflammation results in areas of demyelination in the central nervous system (CNS). The demyelinated areas, called "plaques," lead to slowed impulse conduction in the CNS. Typically, the pyramidal, cerebellar, or optic tracts are involved.7 Weakness, sensory loss, balance disturbances, visual loss, and other deficits commonly occur.

Although the pathogenesis of MS is poorly understood, several well-designed studies have implicated a role for autoimmune dysfunction.8 Immunomodulation is one promising avenue for treatment.9 Moderate exercise appears to enhance immune function, and high intensity or prolonged exercise appears to depress immune function. However, the immunomodulatory effect of exercise is not well understood.10

Pathophysiology of Exercise in MS

Exercise provides an outlet for social interaction and relaxation. Exercise may also increase core body temperature, however, and this is problematic for MS patients. In MS, an elevation of core body temperature as slight as 0.5° C can result in a transient increase in focal neurological symptoms, such as weakness or blurred vision. Known as Uhthoff’s phenomenon,11 this symptom change may occur because demyelinated nerve fiber conduction is extremely sensitive to temperature elevation, which slows nerve conduction. Deficits therefore become more prominent. Because exercise may increase core body temperature, which may lead to transient worsening of symptoms, physicians treating MS patients traditionally recommended limiting or avoiding aerobic exercise. However, this recommendation is not evidence-based.

Clinical Trials

Little information exists regarding benefits of regular aerobic exercise for MS patients. A literature search revealed only one randomized trial. In this study conducted at the University of Utah, a 15-week aerobic training program involved MS patients recruited through the MS Society and through physician referrals in Salt Lake City, Utah. Fifty-four patients were randomly assigned to exercise or non-exercise groups.12 Neurological evaluation, physiological measurements, and psychological instruments were completed at baseline and after study completion.

All patients had mild-to-moderate disability, with Kurtzke Expanded Disability Status Scale (EDSS) scores of 6.0 or less.13 Measurements included validated, pretested instruments known as the profile of mood states (POMS), the sickness impact profile (SIP), and the fatigue severity scale (FSS). A combined arm and leg ergometer, computerized force measurements of maximum voluntary isometric contractions, and body composition analyses were also obtained.14

Three supervised training sessions per week were administered to the exercise group for 15 weeks. At each session, patients participated in a five-minute warm-up period at 30% of maximum aerobic capacity (VO2max), 30 minutes of activity at 60% of VO2max, and a five-minute cool-down, plus five to 10 minutes of stretching during the session. Cooling was achieved via air fans and ergometer airflow.

Eight patients dropped out during the course of the study—six for reasons unrelated either to their MS or the study and two because of MS exacerbations. MS exacerbations that occurred in participants were distributed equally between the exercise and non-exercise groups.

VO2max increased significantly (by 22% vs. 1% in the non-exercise group) after 15 weeks. Significant increases over baseline in upper and lower extremity strength, and significant decreases in skinfolds, triglyceride levels, and very-low-density lipoprotein levels were found in the exercise group. Other significant physiological measures are outlined in Table 1. Patients in the exercise group experienced significant decreases in depression, anger, and fatigue at 10 weeks according to the POMS. On the SIP, patients in the exercise group reported significant improvements in ambulation, mobility, and in body-care and movement scores at 10 weeks.12 These improvements in psychological indicators continued, but were no longer statistically significant at 15 weeks. No adverse effects resulting from the intervention were reported.

Although this study evaluated the effects of aerobic exercise, which improves cardiorespiratory endurance, Tai Chi Chuan and martial art therapy have been reported to confer health benefits as well.15,16 However, the effects of Tai Chi Chuan and martial art therapy in MS have not specifically been studied.


According to the results of a single randomized study, aerobic exercise in mild-to-moderate MS appears to confer the same fitness and psychological benefits that it does in patients without MS. Although the study was not designed to improve muscle strength, favorable changes in isometric force were found as well. Additionally, more long-term study of the effects of exercise on MS patients will be necessary to explore whether exercise might favorably alter the rate of disease progression.


With proper attention to avoidance of overheating, maintaining a regular aerobic exercise program may help MS patients limit disability caused by fatigue and depression. Although the patients in this program participated in a specialized, medically supervised program, MS patients who have received permission from their physicians should be able to reap similar benefits from aerobic exercise programs primarily intended for the general public. Such general exercise programs may need to take into account the special requirements of MS patients and allow them to "tone down" the difficulty of the regimen. MS patients should never be expected to "push their limits" beyond the personal comfort zone, and most certainly should not exercise to the point of exhaustion. Pre-exercise cooling and employment of cooling devices such as air fans during the exercise period are advisable.12 Exercise in cool water may be an ideal form of exercise for MS patients. However, depending on each individual’s specific physical deficits, almost any form of exercise could be adapted appropriately. This study offers welcome encouragement to MS patients to continue to "stay fit," despite their chronic disability.

Dr. Kattapong is a neurologist and principal in MediCat Consulting, a health services consulting firm in Tucson.

A recent randomized trial studying the effect of aerobics on MS patients found:

a. significant increases in upper and lower extremity strength.

b. significant increases in skinfolds, triglyceride levels, and very-low-density lipoprotein levels.

c. significant increases in depression, anger, and fatigue.

d. All of the above.

e. None of the above.


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