DOES GRADED EXERCISE THERAPY IMPROVE POST-EXERTIONAL MALAISE IN CFS? by Susanna Agardy
susanna@nex.net.au

People with CFS/ME are being increasingly urged to exercise to improve functioning. For example, in the Medical Journal of Australia, Prof.  Andrew Lloyd has announced that 'one can safely conclude ...that graded physical exercise should become a cornerstone of the management for patients with CFS'[1] unless they are severely ill.[8]

In the same editorial the problem of post-exertional malaise is acknowledged: '…the cardinal phenomenon of fatigue in CFS is  characterised by a marked and prolonged exacerbation of symptoms following minor physical activity…'[1]. As CFS/ME people with this problem know, this exacerbation is often delayed and brings into play many symptoms. This should be enough to indicate that there is something extraordinary, rather than just exacerbated fatigue happening here. It can be serious enough to stop sufferers from entering exercise experiments or to cause dropping out of them.

Three studies, two of them British[2],[3] and one Australian[4], have been cited as providing evidence for the benefits of GET. All of the studies found significant improvements in fatigue and functioning of a large proportion of CFS participants who completed a graded exercise program compared with controls who did stretching or relaxation or received medical care. Patients' beliefs about the physical cause of their illness were found to change with their improvements in fatigue when used together with CBT[2], or their improvement was interpreted in this light[4].

To what extent can the results of these studies be generalised to people with post-exertional malaise?

1. Two of the studies, which are often quoted, show no evidence of directly addressing what we know as post-exertional malaise and do not even mention it.[2],[3] These studies used the Oxford Criteria of 1991 for CFS formulated by the Oxford Consensus Meeting.[5]

The syndrome definition in the Oxford Criteria for CFS does not include post-exertional malaise. Another section of the Oxford Criteria mentions that '…it should be stated whether the fatigue is greatly increased by minor exertion…'[5], but there is no requirement to include subjects who have this problem. There is no mention of 'increased fatigue' in the studies. In any case, this amorphous and confusing term fails to do justice to the phenomenon of post-exertional malaise.

Only Wallman seems to refer to the problem in stating that there was  'no relapse' during the course of treatment.[4] Wallman required doctors' certificates to state that patients met the Fukuda Criteria6. Although these criteria include post-exertional malaise it is not an essential criterion.

None of the authors show evidence of having ascertained whether the subjects in fact suffered from post-exertional malaise prior to the treatments. Therefore, these studies leave themselves open to the interpretation that at least some subjects in the studies did not suffer from post-exertional malaise to begin with.

2. Fulcher[3] excluded people with sleep disorders, a well-recognised feature of CFS/ME according to the Oxford[5], Fukuda[6] and Canadian[7] Criteria. This could have further excluded CFS/ME sufferers who have post-exertional malaise as part of the syndrome.

3. The studies by Fulcher[3] and Wallman[4] began with pre-treatment assessments including aerobic capacity and target heart rates involving treadmill or cycle testing. These tests would be likely to cause a degree of relapse in most people with post-exertional malaise, for many of whom aerobic exercise is having a shower, or even less activity. The authors seem oblivious to the contradiction of giving CFS sufferers sustained aerobic exercise, maximal or submaximal, before they underwent the carefully designed graded exercise program. Yet, no complaint or problem is reported.

4. The studies are subject to volunteer bias, that is, people who feel well enough to do exercise or think they can perform in such a study will participate and those who are more severely affected will exclude themselves. This may be unavoidable, but the conclusions able to be drawn will be limited.

These studies do not justify claims which imply that graded exercise assists in overcoming the effects of post-exertional malaise. They also cast no light on the problem of sufferers who fail to improve or get worse following exercise. They cannot be generalised to the population of CFS/ME sufferers.

Perhaps the experimenters have not paid attention to post-exertional malaise because they subscribe to the belief system which dictates that most of the limitations to CFS/ME people doing exercise reside within their 'dysfunctional' belief systems and the consequent assumed deconditioning. Where selection of subjects ignores and excludes post-exertional malaise (as with the use of the Oxford Criteria), the experimenters' belief system is perpetuated and remains unchallenged.

For GET studies to have credibility for sufferers of post-exertional malaise they need to demonstrate that the subjects suffered from this problem before and not after the study. This would mean using the Canadian Criteria[7], which requires the presence of post-exertional malaise for a diagnosis of CFS/ME. The studies would also need to take into account variables such as stage and severity of illness and correlate the responses to exercise with some of the physical abnormalities which have been discovered. While there is any ambiguity about this crucial issue people with post-exertional malaise cannot but reject the generalisations from these studies.

References:

1. Lloyd AR. To exercise or not to exercise in chronic fatigue
syndrome? No longer a question [editorial]. Med J Aust 2004; 180:
437-438.

2. Powell P, Bentall RP, Nye FJ, Edwards RHT. Randomised
controlled trial of patient education to encourage graded exercise in chronic fatigue syndrome. BMJ 2001; 322: 1-5.

3. Fulcher KY, White PD. Randomised controlled trial of graded
exercise in patients with the chronic fatigue syndrome. BMJ 1997; 314:
1647-1652.

4. Wallman KE, Morton AR, Goodman C, et al. Randomised controlled
trial of graded exercise in chronic fatigue. Med J Aust 2004; 180:
444-448.

5. Sharpe MC, Archard LC, Banatvala JE, Borysiewicz LK, Clare AW,
David A, et al. A report-chronic fatigue syndrome: guidelines for
research JR Soc Med 1991;84:118-21.

6. Fukuda K, Straus SE, Hickie I, et al. The chronic fatigue
syndrome: a comprehensive approach to its definition and study. Ann Intern Med 1994; 121: 953-959.

7. Carruthers BM, Jain AK, De Meirlier K, et al. Myalgic
encephalomyelitis/chronic fatigue syndrome: clinical working case
definition, diagnostic and treatment protocols. J Chronic Fatigue Syndr
2003; 11: 7-116. Available at: http://www.mefmaction.net/documents/journal.pdf
(accessed Sep 2004).

8. Lloyd AR, To exercise or not to exercise in chronic fatigue
syndrome? [Letter] Med J Aust 2004; 181 (10): 578-580.