Reviewed by: HU Medical Review Board | Last reviewed: March 2022

Fatigue is a debilitating symptom that greatly affects quality of life. It can be both a direct symptom of multiple sclerosis (MS) or as a result of navigating life with MS.1

Fatigue can also be caused or worsened by other underlying health issues.2

What is fatigue?

Fatigue is described as severe weariness. It goes beyond being tired. Fatigue is a constant state of no or low energy that does not improve with sleep or rest.1-3

Some episodes of fatigue may be temporary and have a reversible cause. Other episodes can last for long periods of time and not have an obvious cause. Fatigue that lingers for months or even years can impact physical, mental, and emotional well-being.1-3

Fatigue can affect a person’s ability to complete their daily tasks or enjoy things they love. It can also be hard to explain to friends and family. Fatigue is an invisible symptom, with no obvious external signs. This can lead to confusion or misunderstanding among loved ones and others.4

People with fatigue may have relationship issues if they are being seen as lazy or avoidant when they cannot complete tasks. Finding ways to combat fatigue while still asking for support from others can be challenging.4

It is not always possible to determine the root of a person’s fatigue. However, some common causes include:1

  • Unhealthy diet
  • Too much or too little physical activity
  • Drug or treatment side effects
  • Alcohol or drug use
  • Chronic stress
  • Obesity
  • Chronic pain

Certain health conditions, including MS, can also lead to fatigue. Examples include:1

  • Anxiety or depression
  • Chronic kidney disease
  • Anemia (low red blood cell counts)
  • Chronic obstructive pulmonary disease (COPD)
  • Diabetes
  • Thyroid problems
  • Sleep apnea
  • Head trauma
  • Inflammatory bowel disorders

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Why does fatigue occur in MS?

More than 75 to 80 percent of people with MS report having fatigue. This makes it one of the most common MS-related symptoms. Plus, more than half of those with fatigue say it is their most bothersome symptom.3,5

There are several reasons why fatigue occurs in MS. First, issues with bladder or bowel function can keep people up at night. This leads to disrupted sleep and severe tiredness. Depression, anxiety, and stress can also interfere with sleep and are more common among those with MS.2,5

The physical symptoms of MS may also make it challenging to complete daily tasks. It may take a person with MS more effort to complete something compared to someone without MS. This extra energy and effort can lead to fatigue.2,5

Fatigue can also be a side effect of drugs used to treat MS or other health conditions.2,5

The severity of a person’s fatigue is not related to the severity of their MS. This means someone with few MS symptoms could experience extreme fatigue, while someone with many MS symptoms may have none. However, fatigue does seem to worsen with periods of MS flares. Experts think fatigue is also linked to a greater amount of nerve damage in the brain.5

A specific type of fatigue called lassitude occurs in MS. It is sometimes referred to as MS fatigue and has certain signs. A person’s fatigue may be lassitude if it:2,5

  • Occurs every day, including early in the morning after sleeping all night
  • Gets worse as the day goes on
  • Gets worse in hot and humid environments
  • Suddenly and easily comes on
  • Interferes more severely with normal activities than regular fatigue

It is also possible to develop fatigue separately from MS. Vitamin deficiencies, behavioral factors, other health conditions, drugs, and more can all play a role.2,3,5

Managing fatigue

Fatigue can be hard to treat. The first step is to determine the underlying cause. In some cases, treating the underlying issue may help. This might include things like:2,3,6

  • Exercising more
  • Eating a better diet
  • Stopping a certain drug
  • More aggressively treating another health condition

Your doctor will work with you to determine what factors are involved and look for signs of any fatigue-causing issues.2,3,6

Common options for managing MS-related fatigue include:1,6

  • Creating a reasonable exercise plan
  • Physical and occupational therapy to learn how to complete tasks without spending too much extra energy
  • Wearing cooling vests or avoiding hot environments, since heat slows down nerve signaling and can make MS symptoms worse
  • Starting talk therapy or mental health counseling
  • Eating a more balanced diet and drinking plenty of water
  • Practicing stress-reducing techniques like meditation, mindfulness, yoga, or journaling
  • Practicing good sleep hygiene, such as going to bed at a regular time, removing distractions before bed, and avoiding caffeine
  • Addressing nighttime symptoms like frequent urination

There are also drugs that can be used when behavioral or other options are not working. If your fatigue is consistently severe, talk with your doctor about further treatment.1,6

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