Fatigue or tiredness is one of the most debilitating symptoms of Multiple Sclerosis and one that worries many people. Up to 90% of people with MS experience overwhelming tiredness at least some of the time. Fatigue in MS is often associated with:

• heat (or being hot);
• activity – using motor skills, or being mobile;
• sleep disturbances;
• particular mood states (such as depression – see later section);
• some cognitive problems that may occur in MS (see later section).

At present there is no one known cause of fatigue in MS. Some argue that the best way to manage fatigue is to consider it as a symptom arising from several different sources and thus requiring different techniques to manage it. In fact it might rather better to talk of ‘Multiple Sclerosis fatigues’ in the plural. We could distinguish what we might call:

• normal fatigue resulting from everyday exertion etc., which is managed by rest;
• ‘Multiple Sclerosis fatigue’, which seems to result from the MS itself and for which it is difficult to find any other immediate cause, and which may well require drugs to control it;
• muscle fatigue, which may appear in an arm or leg, for example after or during a walk; rest may be needed and cooling may be helpful here;
• fatigue from depression, often managed through the treatment of the depression itself;
• fatigue from drugs themselves, occurring as a side effect – being aware of this possibility should prompt you to consult your doctor if fatigue seems to be related to a drug you have taken;
• fatigue from the underuse of muscles – just as fatigue can result from overuse, it can also result from underuse, it is important to keep your muscles in the best condition you can.
• fatigue from managing Multiple Sclerosis – living with MS is fatiguing for most people, so pacing your activities as well as taking advantage of as many helpful pieces of equipment as possible will be important;
• fatigue from loss of sleep – this is of course a problem not just for people with MS and will compound other kinds of fatigue, so the reasons you are losing sleep need to be addressed.

Management of fatigue

Although it is important that your symptom is recognized as genuine by medical and other healthcare staff (which has been a problem in the past), you will probably have to manage many of the day-to-day aspects of fatigue yourself, for drug therapies (see below) are often only partially successful.

Self-help

• Identify activities that appear to precede the fatigue and avoid them whenever possible.
• Develop ‘pacing’ strategies, trying to work intermittently with rest periods, or use some other ways of relaxing during the day.
• When the fatigue seems to be related to particular times of the day, focus your activities at other times.
• Try longer term ‘pacing’ too, trying to balance activities over periods of days or weeks.

People with MS may do something that they enjoy or indeed have to do, knowing that they will have a couple of ‘bad fatigue days’ following this activity. However, ‘fatigue management strategy’ tends to be a complicated business, taking a lot of energy in itself to think through all the possibilities that might occur.

Professional support
Specific and carefully planned exercise programmes have been found to reduce feelings of fatigue, but only temporarily. Behavioural therapy can help to alleviate other psychological symptoms that might exacerbate the fatigue, but these non-drug professional approaches have not been successful so far for most people with Multiple Sclerosis over the medium and longer term.

Drugs
Some drugs have helped, the two most well known being magnesium pemoline (Cylert), which stimulates the CNS, and amantadine hydro- chloride (amantadine; Symmetrel), an antiviral agent. It has also been suggested that fluoxetine (Prozac) may help in managing MS fatigue.
Some antidepressants, particularly those that have a low sedative effect, may help the tiredness even if you are not clinically depressed. Beta-interferon drugs may have some effect on fatigue if, indeed, they help the immune system.
Fatigue may be one thing that affects cognition, although it is still not yet clear exactly how this happens. Some people with MS feel fatigued almost simultaneously as they notice problems with their memory or concentration (see below). Self-rated fatigue is linked with certain forms of memory problems, as well as reading comprehension. However, if fatigue is treated with a prescribed drug, it does not appear to influence cognition. In order to try and understand this process, fatigue in people with MS has been compared to that in people with chronic fatigue syndrome (CFS), but it is not clear whether the two are the same; indeed, when fatigue severity is the same between the two groups, people with Multiple Sclerosis showed more widespread cognitive problems.