Functional electrical stimulation and voluntary exercise to enhance cardiorespiratory responses to aerobic exercise in people with advanced multiple sclerosis

Abstract

Multiple sclerosis (MS) is a chronic, debilitating, inflammatory, and degenerative disease of the brain, spinal cord, and optic nerve. Some common symptoms include paralysis or paresis, reduced balance, and fatigue. These symptoms make it difficult for people to be physically active, leading to poor aerobic fitness. Exercise plays an important role in the management of MS, and the benefits of aerobic exercise are well-established for people with mild and moderate MS. However, research into aerobic exercise for people with advanced MS is currently limited, especially concerning which exercise modes might allow a person to improve aerobic fitness. Therefore, the aim of this thesis was to evaluate the cardiorespiratory responses from arm crank ergometry (ACE), cycling, functional electrical stimulation (FES) cycling, and hybrid FES cycling (a combination of ACE performed concurrently with FES cycling) when used by people with advanced MS. The thesis also explored the feasibility of, and changes to cardiorespiratory fitness and fatigue from, training using hybrid FES cycling. Participants with advanced MS achieved a higher absolute exercise intensity during hybrid FES cycling than the other exercise types investigated. Additionally, there were discrepancies between the absolute intensity assessed by metabolic equivalents or heart rate reserve, and the relative intensity assessed by participants’ perception of exertion during, every exercise trial. This thesis demonstrated the feasibility of aerobic training using hybrid FES cycling for people with advanced MS. This study did not detect a change in cardiorespiratory fitness, but there was a reduction in participants’ perception of MS-related fatigue. The overall findings of this thesis provide valuable guidance regarding cardiorespiratory responses and fitness adaptations for people living with MS and clinicians.