Fatigue is the most common MS symptom and, in competition with pain, is the most frustrating for people to manage. It is unpredictable and invisible and is often misattributed, not to the MS disease process, but to depression, denial, disinterest, self-pity, disorganization, poor planning or just plain laziness. As many as 90 percent of people with MS have fatigue–probably half of them experience it every day. One third of people with MS describe it as their most troublesome symptom.

Fatigue is a frequent cause of disability. Fatigue is difficult to define because it is a collection of different symptoms that vary in frequency and intensity. Although fatigue is a big problem, it is a slightly different problem for each person who has it, so it is difficult to measure and therefore difficult to study. It has been the focus of much research to understand what it is, what causes it and how best to improve it. But, to quote from a 2008 study: “For all this, fatigue remains elusive. Without exception, each MS study begins with a comment about the lack of a clear definition of fatigue, lack of understanding of the pathophysiological basis of the symptom, and lack of effective treatment, all the while acknowledging its complexity, importance as a cause of disability and social cost.”


Fatigue is an imprecise term. It is meant to describe tiredness that is out of proportion to the effort exerted, occurs suddenly and unpredictably, and significantly interferes with the necessary functions of everyday life. Because it has many facets, fatigue is difficult to define and it is very difficult to describe to people who don’t have it. We use standard vocabulary words such as tired, exhausted, worn out to describe it, but “tired” does not do justice to the subjective experience of MS fatigue.

The feeling of “tired” is familiar to everyone on the planet. In normal life, we use “tired” as a way to describe how much energy we have expended, but it does not describe how much energy we have left. “Tired” is how we feel after we clean the garage, read a long and dull report or exercise for an hour. Our energy is diminished and we would prefer to rest, but if circumstances demand it, we can override tired, tap our reserves and carry on. Fatigue is tired that cannot be overridden. When people are fatigued, they have run out of energy to the point where rest or sleep is essential. Their reserves are exhausted and they cannot muscle their way through.


Clearly, there are multiple factors that contribute to fatigue. How they work and how they might interact with each other isn’t understood. When people talk about “overwhelming fatigue” in MS they certainly refer to the magnitude of the tiredness and energy loss. But “overwhelming” also describes the complexity of the problem.

Treating MS fatigue is very complicated. Figuring out what to do about it all can be overwhelming. Where do you start? It isn’t true that there are no good treatments for MS fatigue. It is true that there is no single, easy-to-find and simple-to-do treatment. There are ways to improve MS fatigue but just as the symptom is not straight forward, neither are the solutions. Most MS fatigue is caused by a combination of factors that each contributes a bit to the development of fatigue.

The solution, therefore, is likely to be a combination of little changes that create gradual improvement. There are two types of interventions to manage fatigue. There are medications and there are other, mostly behavioral, interventions such as sleep, cooling, energy conservation strategies, exercise and cognitive behavioral therapy. Making changes to manage fatigue is, to some extent, about giving in to MS. It is about acknowledging that MS does create some real problems and impose some real restrictions. You can’t simply muscle your way through and pretend they don’t exist, and still have a life.

MS fatigue is a real and very complicated problem. It takes time and thought to identify solutions that will work for you. Be patient.

It is also important to develop realistic expectations. It is unlikely that you will discover a perfect solution. We often expect interventions to be as rapid and effective as penicillin is at treating strep throat and that is not the case with MS fatigue.

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