Multiple Sclerosis Minute: Physical Activity & MS

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system (CNS) with secondary neurodegenerative processes.¹ The estimated prevalence of MS is 1 million adults in the US.² MS is clinically characterized by relapses, lesions in the CNS, and progression of neurologic disability. Those clinical expressions are brought about by periods of inflammatory demyelination and transection of axons as well as neurodegeneration involving loss of trophic support of neurons. The disease pathogenesis and resulting CNS damage manifest as dysfunction (eg, cognitive impairment) and symptoms (eg, fatigue and depression) that compromise activities and quality of life (QOL).

MS is typically treated with disease-modifying therapies (DMTs) that target immunologic signaling proteins (eg, interferons and cytokines) and populations of immune cells (eg, lymphocytes). The DMTs reduce relapse rates and slow disability progression by reducing inflammatory activity. DMTs neither control neurodegenerative processes nor cure the disease, however, and further do not target dysfunction or the symptoms of MS. This highlights the need for identifying other approaches that can improve function, manage symptoms, and optimize QOL and participation in activities of daily living.

There has been a steadily increasing body of research on exercise training among persons with MS,³ and this has accelerated sharply in the past decade.⁴ This review provides an overview of exercise and its benefits, safety, and prescription in MS. Collectively, this paper serves as an overview and reference for researchers and clinicians interested in the promotion of exercise in persons with MS.

Scope of Exercise Benefits in MS

We recently published a review of 54 clinical trials carried out between 2006 and 2016 regarding the range of exercise benefits for people with MS.³ Exercise was associated with positive effects on walking/mobility, neurologic disability, pain, cardiorespiratory fitness, muscular strength and endurance, body weight, balance, mental health (ie, depression, anxiety, cognitive function, and fatigue), and QOL.³

Another review organized the benefits of exercise in MS based on the International Classification of Functioning, Disability and Health (ICF) model (Figure).⁵ This includes evidence for exercise effects on MS pathogenesis (eg, inflammation), body structures (eg, axonal damage), body functions (eg, fatigue), activities (eg, walking performance), and participation (eg, QOL) outcomes.⁵ The application of the ICF model essentially facilitated the classification of existing evidence on benefits of exercise into focal categories along the MS-disease process.

Safety of Exercise in MS

The safety profile of exercise been described in a recent review of exercise in persons with MS,⁶ and this is critical for informing decisions and recommendations regarding safety. We focused on adverse events (AEs) in randomized controlled trials (RCTs) of exercise training in MS. We searched electronic databases for RCTs of exercise training in MS. We calculated the rate of AEs, and the relative risk of AEs for exercise training vs control in 26 studies that included 1,295 participants. The rate of AEs was 1.2% for control and 2.0% for exercise with a relative risk of AEs for exercise training of 1.67. The risk of AEs was no different when compared with evidence from the general adult population who participate in exercise. The most common AEs involved musculoskeletal issues (eg, low back and joint pain) associated with resistance exercise training. This evidence should reduce uncertainty regarding the safety profile of exercise training in MS.

Prescription of Exercise in MS

There are 2 primary resources or guidelines for prescribing exercise for people with MS.^7,8 One was developed based on a systematic literature review of exercise training interventions in MS.⁷ The resulting guidelines suggest persons with MS who have mild or moderate disability engage in at least 30 minutes of moderate-intensity aerobic activity twice weekly and strength training exercises for major muscle groups twice weekly. Aerobic and resistance training can be performed on the same day, but sessions should be separated by 24 hours (ie, not performed on consecutive days). This prescription should yield fitness benefits and possibly reduce fatigue, improve mobility, and improve components of health-related QOL (HRQOL). Importantly, these guidelines have not been formally tested, and require evaluation before broad application, particularly among those with advanced disability with MS.

Another set of guidelines was developed via a scoping review of existing exercise prescription resources for MS, stroke, and Parkinson disease (PD) with the aim of providing uniformly recognizable exercise recommendations for clinicians and patients/clients.⁸ These guidelines were synthesized from resources reporting aerobic and resistance training guidelines for MS, stroke, and PD. Regarding MS, the systematic search yielded 10 eligible resources from electronic databases and textbooks or websites of major organizations. Data were extracted, including exercise frequency, intensity, time, and type, and synthesized into recommendations per disease. Exercise guidelines for MS consistently recommended 2 to 3 days/week of aerobic training (10-30 minutes/session at moderate-intensity) and 2 to 3 days/week of resistance training (1-3 sets/session of 8-15 repetitions each). The frequency ranges between 2 and 3 days/week and should generally start with 2 days/week and progress toward 3 days/week over time. Duration of exercise ranges from10 to 30 minutes and should gradually progress from 10 to 30 minutes over time. The intensity should be moderate and range between 11 and 13 on the 20-point rating of perceived exertion scale, or between 40% and 60% peak oxygen consumption or peak heart rate. Overall progression should start with increases in either duration or frequency. Progressions in intensity should be based on the tolerability of the individual with MS, only after duration and frequency are well tolerated. This harmonizing of exercise guidelines provides a prescriptive basis for healthcare providers, exercise professionals, and people living with MS regarding disease-specific exercise programming.

Exercise Participation Rates in MS

A major caveat in the therapeutic use of exercise and physical activity among those with MS is the high rates of physical inactivity observed among people with MS. Guidelines for physical activity among people with MS (Table) have also been reviewed.⁹ Meta-analyses have demonstrated a consistent pattern of low levels of physical activity participation in persons with MS compared with the general population of adults without chronic disease.^10,11 There is additional evidence that only 20% of persons with MS engage in appropriate levels of moderate-to-vigorous physical activity compared with 47% of individuals without chronic conditions.^12,13 This underscores the importance and opportunity for exercise promotion in MS, perhaps through the patient-provider interaction in comprehensive MS care.

Promoting Exercise in MS

There is a large interest among persons with MS in opportunities for exercise participation for managing their disease and its manifestations, and this interest may be addressed through the patient-provider interaction in comprehensive MS care. See the Box for physical activity tips to encourage participation. Indeed, our formative, qualitative research indicates that both patients and providers believe that exercise can be promoted in the context of comprehensive MS care.¹⁴ We have developed and refined conceptual and practice models for exercise promotion primarily through neurologists and supported by nurses, physical therapists, occupational therapists, and other rehabilitation professionals.¹⁵ The application of these resources in practice models may be a major step forward in the promotion of exercise as a disease-managing behavior among persons with MS.

Summary

There is increasing evidence for the role of exercise in managing MS disease pathophysiology, functions, and symptoms as well as optimizing QOL and participation outcomes. There is evidence for the safety of prescribing exercise for MS. There are exciting opportunities for exercise and neuroplasticity in MS, and the promotion of exercise by health care providers represents a novel approach for managing MS itself and the many consequences of this disease.¹⁶