Exercise and Neurological Disorders II:
Multiple Sclerosis (MS)
In a strange way, it’s really given me purpose in life. And it’s kind of the reason I’m in the game, because I really want to defy the odds. - Lina Nielsen, GB Athlete.
What is MS?
Multiple Sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system (the brain and spinal cord). Put simply, this means that the body mistakenly attacks itself, specifically the nerve cells in the body. Let’s take a deeper dive into this.
Our nerve cells, or neurones, can be either myelinated, or unmyelinated. This refers to the presence or absence of a protective layer around the neurone, known as the myelin sheath. In myelinated neurones, the myelin sheath acts as an insulating layer, which accelerates the transmission of electrical impulses across the nervous system. When sheaths are damaged, either in the case of MS or other demyelinating disease, these impulses are transmitted at a relatively lower speed, or even stopped altogether. This process also causes inflammation, and can lead to difficulty performing basic motor tasks. Eventually, plaques, or scleroses, form giving MS its name. The diagram below, neatly shows the difference between a healthy neurone and a damaged myelin sheath caused by MS.
Prevalence and aetiology
The Multiple Sclerosis International Foundation estimates that approximately 2.8 million individuals have MS across the globe. Diagnosis typically occurs in those between the ages of 20 and 40, but it is possible for older adults and young children to receive diagnoses, too. Women are more often diagnosed than men – making up anywhere between 60-75% of all cases depending on the figures.
The aetiology of MS is complex, but it is commonly suggested that there are both genetic and environmental factors. Certain genes, such as ApoE and TGF are reportedly associated with the severity of MS, but no single gene appears to be associated with all aspects of the disease. The genetic component is supported by research in twins, with a 1 in 4 chance of a twin developing MS if the other is diagnosed, as opposed to a 1 in 334 chance for other biological siblings. A high-profile example of this, especially in the UK, would be the Nielsen twins, who will shortly be competing for Team GB in Paris for the 2024 Olympic Games.
Potential environmental factors that may contribute towards the development of MS include:
Vitamin D deficiency and geographical factors
This is also slightly genetic, as research suggests that those with lower natural levels of vitamin D due to their genetics may be at higher risk of developing MS. Conversely, there is no current evidence to suggest that increasing vitamin D levels can improve symptoms, or reduce the risk of developing MS. There is a potential geographical link here too – we know that MS appears to be more prevalent in countries which are further from the equator, and therefore may naturally get less sunlight, and subsequently produce less vitamin D, but further research is needed.
Epstein-Barr Virus (EBV)
The EBV is one of the most common infections worldwide and is often asymptomatic. However, in younger adults or adolescents, it is responsible for mononucleosis (mono), which can cause fatigue, muscular aches, and fever. Reviews have concluded that EBV infection can increase the risk of MS by 30x, but again, further investigation is required. 1
Smoking
Not only may smoking increase the risk of developing MS by up to 50%, it also increases the speed of onset of disability for those with the disease.
Symptoms
There are many possible symptoms, but the most common are:
Pain
Muscular weakness
Fatigue
Visual disturbances
Numbness and/or tingling
Cognitive decline
Bladder and/or bowel dysfunction
Motor task difficulty
Clinical Courses
Disease progression is different for every individual, but there appear to be four main courses of progression for MS.
Relapsing-remitting
This form of MS is characterised by stages of disease relapses with a full recovery or a deficit after recovery. During the recovery stage there is no progression of symptoms.
Primary progressive
In this form, the MS progresses with small, infrequent plateaus or minor, temporary improvements. Symptoms tend to worsen over time.
Secondary progressive
This stage begins as relapsing-remitting, but then progresses as symptoms worsen.
Progressive-relapsing
This form is progressive from the start but may have short relapses with or without full recovery.
How can exercise help?
Exercise can provide many benefits or those with MS. It can aid with the fatigue-related symptoms, as well as improve balance, co-ordination, strength, endurance, mobility and flexibility. For a breakdown on specific guidance, see below.
Cardiorespiratory exercise
Individuals with MS may have an elevated cardiovascular risk. Given that they are also likely to have lower energy and fitness levels and balance issues, certain precautions should be taken. When assessing aerobic function, bicycle ergometry is typically recommended, but treadmill testing may also be possible depending on the individual’s level of ambulatory impairment. The individual may also present with a blunted HR response, so it important to monitor for muscle weakness, fatigue, and signs of impaired thermoregulation. A typical assessment of aerobic function may involve 5 minutes of light intensity exercise as a warm-up, followed by 2/3-minute stages, incrementally increasing the workload by an absolute output of 10-25W per stage.
Once obtained, cardiorespiratory training is recommended to be completed on 2-5 days per week, between 30-60 minutes per session depending on the individual. It should be of moderate intensity, between 12-15 on a 20-point RPE scale. If needed, the session can be broken into manageable bouts of 5-10 minutes until satisfactory volume is achieved. As a practitioner, we should be mindful of impaired thermoregulation, be sensible with exercise modes, and ensure that total exercise time is increased before exercise intensity.
Resistance exercise
Whilst assessing strength and exercise function, 1RM testing, as with a healthy subject, is advised. However, certain muscle groups may be preferentially weaker, and if necessary, 5RM testing may be more sensible. For assessment of muscular endurance, 30RM can be obtained. Machine weights are generally recommended but can be adapted depending on the individual. If the individual is stiffer, less flexible, or more disabled, then manual muscle testing may be preferential, and practitioner supervision is paramount to safety.
Similar to healthy populations, resistance exercises should be performed on 2-3 days of the week, for up to 30 minutes per session. Once assessed, subjects should ideally perform 2 sets of each exercise for the major muscle groups, up to 15 repetitions per set, at an intensity of 65-80% 1RM (either as assessed or estimated from 5RM). If the individual feels particularly fatigued on a certain day, rest periods can be extended from 2 minutes up to 5 minutes. Resistance exercise should not be performed on consecutive days. As previously mentioned, machine weights are preferable, but band work, calisthenics, and aquatics are also suitable. If a spotter is present, free weights can be performed in a controlled manner and under supervision.
Finally, particular attention should be taken to attenuate any imbalances; it may be sensible to perform unilateral testing to gain baseline measures and allow for regular monitoring.
Range of motion and balance exercise
As a practitioner, it would be useful to gain objective measures of flexibility. Therefore, if possible, goniometry on the knee, hip, ankle, shoulder and elbows should be performed. This can be done at baseline and at subsequent regular intervals. Special care should be taken to be mindful of spasticity and contractures during this testing.
Range of motion exercises should be performed regularly. At the very least, they should be performed after every training session, but ideally most days of the week. A general programme for increasing flexibility is sensible, with stretches for the major muscle groups being held at the point of tightness for up to 60s, for 2-4 repetitions. Massage and/or yoga may also be beneficial for the individual.
With regards to balance: general upright/standing balance training is recommended. Examples include heel-toe walking, single leg standing, balance walking, and leg raises to the back and side (hip extension and abduction). If too easy, then progressions of these exercises can include introducing an unstable surface, or performing the exercises with their eyes closed, under close supervision of course.
Conclusion
It is clear that, when performed safely, correctly, and under professional supervision, exercise interventions are extremely effective at delayed disability associated with MS. However, precautions must be taken to adapt the training plan to fit with how the individual feels on the day. Ultimately, this should help with activities of daily living, and also improve psychological outcomes.
i Bjornevik, K., Münz, C., Cohen, J.I. et al. Epstein–Barr virus as a leading cause of multiple sclerosis: mechanisms and implications. Nat Rev Neurol 19, 160–171 (2023). https://doi.org/10.1038/s41582-023-00775-5