in MS is one of the greatest concerns that are shared by all people
with MS – regardless of which type of MS an individual has. For the
majority of the general public, it is also one of the most
Often people with MS have to fight not only the symptom, but are often
required to continuously explain or even defend one’s self against
criticism. For example, some families or friends will accuse the person
for being lazy or ‘not trying hard enough’.
Even many ‘experts’ particularly physical therapists will attempt to
convince the person with MS that the fatigue they suffer is due to a
lack of endurance because of insufficient exercise.
There are several types of fatigue in MS – but regardless of which type,
fatigue to us feels more like complete exhaustion – unlike anything
most of us have ever suffered before! It goes way beyond tired!
All people, whether they have MS or not, suffer from ‘normal’ fatigue. This is the fatigue you feel after working or playing hard, or from having a ‘late night’ or disturbed sleep.
All people, also suffer from fatigue which is caused by insufficient endurance levels.
In an able bodied person this may be caused by a lack of over all
general fitness – or by pushing beyond ‘normal activity’, such as
working long hours, extreme physical exertion etc.
However, people with MS also suffer from two additional types of fatigue, which
is not generally understood by family and friends. These are often
referred to as nerve/muscle fatigue and general overwhelming fatigue
with a sudden onset.
The nerve/muscle fatigue is caused by damage to the myelin sheath
surrounding the nerve fibers. The impulse to move travels along and
fires at the appropriate places. However, if there is any
demyelination, the nerve fires, short circuits, fires, short circuits
and then becomes blocked – this is what is called a conduction block.
An example of this would be if you are walking fine, and then the more
you walk the weaker the leg or legs become and eventually you are
unable to lift your leg any further.
Lassitude is what most people are referring too, when talking about "MS Fatigue".
This is generally an overwhelming, sometimes with an alarming sudden
onset of ‘exhaustion’. The desire to sleep or nap may become so
overwhelming that nothing else is possible except to find a quiet place
Generally, MS fatigue seems to worsen as progression continues. Neurologists
believe that this type of fatigue has a neurological – neurochemical
origin, maybe an imbalance of neurotransmitters.
However, if you study the causes and need for sleep in all sentient life forms
you will find that the actual purpose for sleep is rejuvenation of the
body cells, and redirection of energy to healing. This may be likened
to a concentrated effort to repair the body rather than having to
divide the body’s resources in maintaining alertness and function plus
Therefore, it makes intuitive sense that a body that is diseased or damaged will
require more sleep in an effort to repair itself at least at a cellular
level. So that the desire to sleep is ‘induced’ in an attempt to enable
repair. Personally, I believe that both theories have merit.
Another form of fatigue suffered by people with MS may be induced due to clinical depression, which is caused by a chemical imbalance within the brain. However, in
clinical depression, people often report lack of sleep, insufficient
nutrition due to lack of appetite and an overall general feeling of
Therefore, it is almost a ‘chicken and egg’ debate of whether the fatigue of
depression is caused by a chemical imbalance or whether it is due to
lack of sufficient sleep and nutrition.
Clinical depression – not to be confused with depressed mood or grief reaction
to disability -–does respond well to anti-depressants, which indicates
that the depression is caused by a chemical imbalance. The fatigue
which accompanies, depression also lifts. The older types of
anti-depressants had a sedating effect, whereas the newer drugs, such
as Zoloft, Paxil and Prozac are reported to have an energizing effect.
Fatigue may also be induced by chronic pain and unrelenting stress.
You will recall in the article about stress aggravating pain can cause
exhaustion. Spasms and spaticity can also induce fatigue through
inefficient or lack of restful sleep. As most of us know it is when we
relax and finally try to sleep that many of our spasms occur.
Heat, illness causing an increase in body temperature, such as infections, can also cause fatigue.
Some medications we take for spasms are also known to have a sedating
effect, such as Zanaflex, whereas Baclofen causes an increase in
weakness in some people.