Marie Thomas, member of the new Psychology Centre for Health and Cognition, discusses her research into chronic fatigue.

Fatigue is a fascinating topic to research because we can all identify with it. There are two types of fatigue - physical and mental - and we are all aware of how these present. If we go for a run, do some serious cleaning or gardening, for example, we feel physically fatigued. When we stay up late and do not get enough sleep, or studied too hard, we feel mentally fatigued. Infectious diseases such as influenza and glandular fever can result in our joints aching and legs feeling heavy. In addition, these illnesses can create a mental fog where the person feels as if they are not thinking clearly.

We have all experienced fatigue in our lives. From the point of view of a clinician or, in my case, a researcher, the problem is that fatigue, like many other sensations such as pain, is subjective in nature. What is tiredness to one person could be interpreted as exhaustion by another. This makes it difficult to quantify or measure. It is a bit like the conundrum of measuring quality of life – we all come at it from our own perspective.

Fatigue vs chronic fatigue

Fatigue can be the result of physical or mental exertion (acute), as we have seen, or it can be due to illness. In the case of influenza, the fatigue experienced is relatively short lived. As our bodies recover from the assault on our body of a virus, fatigue resolves, and we return to our usual functioning. This can take up to six months in the case of glandular fever. If fatigue is still present after this 6-month cut-off, it is considered persistent or chronic in nature. In Chronic Fatigue Syndrome (CFS) (sometimes referred to as myalgic encephalomyelitis or ME), mental and physical symptoms of fatigue can persist for several years without change.

When we talk about chronic fatigue (CF), we are referring to physical and mental fatigue that is not resolved by rest. It is something tangibly different and more severe from the fatigue most of us feel. People with CF do not experience restorative sleep and do not feel refreshed when waking. Symptoms associated with mental fatigue include poor concentration and problems with everyday memory. This means that individuals have difficulties reading books – they find themselves re-reading the same paragraph over and over again. They also find it a challenge to follow complicated plot lines on TV or in films.

Management and intervention

Fatigue that is chronic in nature can seriously affect quality of life. It can, however, be managed. Cognitive behavioural techniques have been shown to be effective. For some, a negative link is made between fatigue and physical exertion, and this can act as a barrier. By overcoming any negative associations, a person is able to gradually increase their exercise levels and reduce their levels of fatigue. My research into CFS has largely focused on such approaches, measuring fatigue subjectively and objectively through a combination of questionnaires and computer tasks. These measures were then used to evaluate recovery following the intervention.

We now find that chronic fatigue crops up more and more in a range of long-term conditions. The fatigue experienced is such cases is separate from the underlying condition. Research is ongoing to see if we can measure fatigue and its associated symptoms across a range of diagnoses. We began by looking at developmental coordination disorder (DCD) – a neurodevelopmental disorder affecting fine motor movement and coordination – and found that the profile here was similar to that seen in CFS. We are now looking more widely at neurodegenerative disorders, namely multiple sclerosis, Parkinson’s disease and early stage dementia.

Find out more

To learn more about Marie's research, and the work of others in the areas of psychology, health and cognition, visit Bath Spa's Psychology Centre for Health and Cognition.