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What causes fatigue?

Before attempting to present a model of CFS, let us look at some of the factors that a variety of research has shown can play a part in this condition. We will look at this in three sections. Factors that tend to keep CFS going, factors that start it off and factors that make you more likely to get it in the first place.

First though, a word of caution. All, some or none of the information below may apply to you. It doesn't actually matter. If it helps you too make some sense of your condition, fair enough. If it doesn't, ignore it. The most important part of this web site is the self help. We know this works in the majority of cases. If the below means nothing to you, then proceed to the self help section and try it anyway.

Who gets fatigue?
Doing things to our bodies
The pressures of life
Lifestyles and life events
What starts fatigue?
What can keep fatigue going?


Who gets fatigue?

If we look at fatigue in general, rather than CFS in particular, two things are immediately apparent. Firstly it is very common, over 30% of the population experience fatigue at any one time. Secondly there are a variety of causes for it. Listed below are just a few.

Doing things to our bodies

To begin with the obvious, not sleeping can make us tired. We get fatigued after exercise. Being ill often results in tiredness. Most "recreational drugs", both legal and illegal will make us tired, though maybe not till the next day. Having an intense emotional or physical experience - arguments, sex, shock, violence - these will fatigue or exhaust us. Not drinking enough fluids can make us tired. This is all predictable, short term "normal fatigue". Fatigue here is telling us to stop what we are doing and to let our body recuperate for a while. However some fatigue is more long term, less obviously useful. Here the links between what we do and how we feel are less obvious.

The pressures of life

Both from research and anecdotal evidence, it is now clear that anyone under stress is more likely to become fatigued and/or ill. Some of the reasons for this are only just becoming clear and are the subject of a new field of medicine -psychoneuroimmunology. As the name suggests, this studies the links between life events, the way we perceive and cope with those events, the functioning of our brain and nervous system and the functioning of our immune system.

At last there is a scientific basis for what has been obvious to most of humanity for most of the time - stress makes us ill.
A brief word on the mechanism of this. Consider short term stress. The principle purpose of the stress response is to allow us to cope with situations requiring rapid response. A fire alarm goes off, a child has an accident, a chip pan goes on fire - what happens to our bodies?

First of all our sympathetic nervous system switches on. Our pulse and blood pressure go up, our breathing rate increases. This mobilizes energy. Our pupils dilate to let in more light. other parts of the body - our digestive system, our hands and feet, - get resources diverted away from them (thus cold feet and butterflies).
All this allows us to make a quick response. If the stress is present for longer, another physical mechanism kicks in.

This is the hypothalamus - pituitary -adrenal system. This acts by regulating chemicals such as cortisol which have wide ranging effects on the brain, and our nervous, immune and hormonal systems. The results of the activation of this system are again, in the short term, beneficial. Cortisol increases our ability to distinguish between sensations - thus the "heightened awareness" people often report in extreme situations (good or bad). it also mobilizes adrenaline allowing us to access an intense burst of energy.

However the effects of a prolonged or repeated stress response are less good. Animal and human studies have shown that prolonged stress leads to a profound alteration in our immune functioning. We are more likely to catch cold under stress; latent viruses such as herpes are more likely to express themselves. The immune system is complex and still only partial understood, but the overall effect of prolonged stress is to decrease the functioning of the immune system.

Continuing stress will also lead to long term alterations in our levels of neurotransmitters, our hormone levels, all of which in turn will effect our mood and energy levels (for the worse). It also now clear that depressed mood leads to a depressed immune system and vice versa. The pieces of this puzzle are still being put together, but the fact that stress leads to profound, if subtle, changes in our functioning - at all levels - is now beyond doubt.

Lifestyles and life events

We know that certain life events and lifestyles make more people prone to fatigue and illness. People who develop fatigue problems are more likely to have had major life events happen to them in the year previous to developing the problem. Life events can be either positive or negative - marriage, bereavement, changing job, moving house, the break -up of a relationship. All of these will exert there toll on the individual. For instance a study done of divorced couples showed that they had significantly more depressed immune functioning than average, and that there was significant correlation between the level of immune depression and the level of ongoing emotional attachment to the relationship.

Certain lifestyles are more subtly fatiguing. Having little rest, working under pressure, being a single parent, looking after an ill relative, being unemployed. In a way these are obvious sources of fatigue. Less obviously the kind of lifestyle the sports enthusiast or athlete has puts the same kind of pressure on their body, even though it is perceived as positive. It is now clear that the immune functioning of training athletes is lower than normal, their tendency to fatigue and illness is greater.

Personality Factors: It is now clear that a tendency towards hostility and aggression is positively correlated with a tendency towards heart disease. Recent evidence has shown that a tendency to suppress strong emotion and to avoid conflict is positively correlated with the development of certain types of cancer. Is there any type of personality that is more likely to develop Fatigue?

There is some evidence that there is. People who are more inclined to set high standards for themselves and their performance, who have a tendency towards perfectionism seem more likely to get fatigued. In a way this makes sense. If you decide that you have to perform 100% all of the time, you are going to be expending a lot more energy than someone whose expectations are less high. Also if you decide that you always should be able to perform at peak level, you will be less tolerant of tiredness and more likely to push yourself when you should rest

What starts fatigue?

Physical Illness does appear to be present at the beginning of the majority of cases of Chronic Fatigue. Having a viral infection certainly makes us fatigued, in some cases for up to three months after we first contracted it. So a virus can certainly seem to trigger a CF problem. Research from our group and others has suggested that some infections are more likely to trigger the illness than others - viral meningitis, glandular fever and Q fever for example, but so far there is no evidence that the virus is still there after the initial infection is over. Traces of the virus can, of course, often be found, but there is no evidence the virus continues to exert a long term influence. This is not HIV in which viral persistence continues in a harmful fashion.

As mentioned above, major life events are common in the lead up to CFS.

Sometimes there is no obvious reason why someone, either gradually or suddenly, gets more and more tired, then exhausted, then pained and disabled. Whatever the reason, the overall effect is a sudden or gradual inability to keep up the kind of life they previously did.

What can keep fatigue going?

How we cope makes a difference
Take the example of heart disease. Rehabilitation from a heart problem can take a variety of courses. In one scenario the individual becomes fearful of any exertion, believing that this increases the likelihood of another heart problem. They feel helpless and under threat of death. If they are a smoker or drinker or over-eater it is possible that they resort to more of these behaviours because of the stress. They become anxious and demoralized.

The combination of inactivity, fear, helplessness and use of food and drugs does indeed make them more likely to another cardiac incident.
In an alternative scenario, the same individual adopts an approach of gradual re-introduction of exercise, reduction of stress and stressors and develops a feeling of being in control of their recovery. Prognosis thus improves.

More subtly, in recovery from cancer, the individual's beliefs about outcome have been shown to be important. On receiving diagnoses, individuals who adopt either the fighting it attitude, or who go into denial, have a better chance of survival than those who feel hopeless and helpless. Prognosis in recovery can be improved by helping people change the way they manage their illness.

What this demonstrates is that there are several factors at play in illness and recovery. First there is the bare physical fact of the illness. Secondly there is how that makes us feel emotionally and how we believe we should handle it. Thirdly there is how we actually do handle it. The second two factors are as important as the first. It is no different in Chronic Fatigue. Some ways of managing are more helpful than others.

However due to the controversy surrounding CFS, sufferers have often been given conflicting advice or advice that is not, in the long term, necessarily helpful. Equally suffers may be merely following the dictates of their bodies - if something causes pain or fatigue then one naturally avoids that something.
Let us look in more detail about what we know to be useful and less useful ways of managing CF problems.

The natural response to an illness is to rest. There are few illness where, in the short term, one would not be advised to rest. However in CFS, one is often advised to rest, rest and more rest, over a prolonged period of time. We are now beginning to realize that this is not a good thing. Prolonged rest has been shown to be detrimental on a number of levels.

Physically it leads to deconditioning of the body, affecting the immune system, the muscular system and the nervous system adversely. Even a healthy individual if forced into prolonged rest, will fairly quickly become much less healthy. They will lose about 3% of there muscle mass a day, become progressively weaker and more prone to illness.

Mentally, over-resting leads to sluggishness, lack of motivation and concentration and low mood. Particularly if one feels one has no alternative but to rest, one becomes s frustrated and demoralized.
However this is not to say don't rest. Rest is essential, be we fit or ill. Indeed another factor that appears to be common in the onset period of Chronic Fatigue Problems is too little rest. People often struggle on through illness, attempting to maintain a lifestyle that is beyond them, resulting in them becoming more ill and fatigued. Eventually they crash.

Again in Chronic Fatigue problems, people often develop disturbed sleeping patterns. Often this will take the form of having poor quality or unrefreshing sleep at night, often for more hours than prior to illness, followed by day time sleep to compensate for feeling so tired during the day. Several things are going on here.
Firstly we know that, as with resting, it is possible to oversleep, that sleeping more makes us more tired and sluggish during the day.

Secondly there is a vicious circle at work. If we sleep during the day this reduces the quality of sleep at night which in turn makes us more tired during the day, which makes us more likely to sleep during the day, which reduces sleep quality at night... and so on. More subtly, if we spend a lot of the day resting and unstimulated, there is less need for deep prolonged sleep at night, even though we may feel more exhausted than when we were active.

This lack of good quality sleep can lead to further frustration and exhaustion, more resting and more daytime sleep which in turn...
In short, once our sleep rhythm is disturbed, it can have profound effects on how we feel. Managing this differently can make fatigue problems better or worse.

If activity leads to pain and exhaustion, it is only natural to avoid it and to rest until we feel up to it. This often happens in CFS. Individuals will save energy in prolonged rest, be active for a while then, perhaps a day later, feel the physical effects of that activity - exhaustion, muscle pain - and then rest again for long period.

This boom and bust cycle tends to be typical of CFS. Again there are certain elements of a vicious circle in this pattern. If activity produces pain and exhaustion we avoid it. The more we avoid it, the less able we become to do it. When, for whatever reason, we are forced to do it again, it produces even more pain and exhaustion, this leads to more rest and avoidance.
Eventually, as with any other Chronic Illness, particularly one where there appears to be no hope and the sufferer feels that they have little control over their condition, demoralization and depression often occur. These feelings make an already bad situation worse.

Author: Vincent Deary
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