Aerobic Exercise and Brain Health in Multiple Sclerosis

Multiple Sclerosis (MS) is a physically and cognitively disabling, chronic autoimmune disease of unknown etiology. It is the most common neurological disease affecting young adults in Western countries. According to the Danish MS Registry the prevalence has increased markedly over the last 40 years for particularly women, and today there are approximately 14.000 patients with MS (PwMS) in Denmark.

The pathological hallmark of MS is sclerotic plaque. Plaques in the central nervous system (CNS) can be detected in vivo using magnetic resonance imaging (MRI). Both the accumulation of lesions and the accelerated whole-brain atrophy correlate with the progressing physical and cognitive disabilities that clinically characterize PwMS.

The disease causes damage of both white and grey matter in the CNS, leading to whole brain atrophy and topographically specific atrophy within the hippocampus and the frontal and temporal cortices. The degradation of the CNS manifests as cognitive and physical disability. Cognitive impairment is estimated to affect up to 65% of PwMS, making it one of the most common and disabling symptoms of MS. Medical therapies for cognitive impairment in MS have so far proved ineffective. Collectively, the prevalence, impact and missing treatments highlight the importance of alternative approaches towards preservation of cognitive function. Despite equivocal findings, aerobic exercise represents a promising approach towards preservation or even expansion of hippocampal volume and cognitive functioning in MS. No longitudinal randomized controlled trial (RCT) study has so far applied the MRI technique when evaluating the potential neuro-protective effect of exercise on brain structure and function in MS. Also, given the scarcity of effective treatments for cognitive impairment in MS, a longitudinal exercise intervention evaluating the potential effect of aerobic exercise on cognition is urgently needed in MS.

The purpose of the present project is to investigate how aerobic exercise affects brain volume, specific brain regions, neurotrophins and cognition in PwMS.

It is hypothesized that aerobic exercise can slow down brain atrophy, increase the size of hippocampus, upregulate the secretion of neurotrophins and improve cognitive performance in people with MS.

The study will be a single blinded RCT. The exercise intervention will contain 6 months of aerobic training (bicycling, rowing and cross trainer) performed two times a week at moderate to high intensity and under supervision. The control group will be "living as usual" and will be offered the same exercise intervention after a 6 month period. A total of approximately 85 PwMS will be expected to be enrolled. The primary outcome of the study will be brain atrophy determined by MRI.

The current interdisciplinary project aims to document and understand the possible neuro-protective effects of exercise in MS. This would be of high relevance to PwMS (and other neurological pathologies). From a societal perspective it would help optimize MS rehabilitation and subsequently reduce MS related costs due to disability. In case of positive findings, this would provide the first convincing human evidence of a disease modifying effect of exercise in MS.