with chronic fatigue syndrome: evidence-based
practice guidelines* by Van Cauwenbergh D et al -
Eur J Clin Invest. 2012 Oct;42(10):1136-44. doi:
10.1111/j.1365-2362.2012.02701.x - can be found
LETTER TO THE EDITOR
Irish ME /CFS Association, Dublin, Ireland
Eur J Clin Invest 2012
There is much that is praiseworthy in Van
Cauwenbergh et al. review of exercise
interventions for Chronic Fatigue Syndrome (CFS).
I particularly like their dichotomisation of studies
based on whether a symptom-contingent or
time-contingent approach was utilised, which has
been missed by previous reviews .
I would, however, like to respond to some points.
They twice claim the time-contingent approach
tested in Wearden et al.  showed significant
improvement (P < 0.05) in fatigue and physical
functioning compared with the controls.
However, what the trial actually found was, upon
completion at 20 weeks, the intervention showed
only an improvement in fatigue while at 70 weeks
(the primary outcome point), there was no
improvement in either measure.
The review fails to sufficiently highlight an important
flaw in the research evidence base: the almost
complete lack of objective evidence for the
subjectively reported improvements reported for
cognitive behavioural therapy (CBT) and graded
exercise therapy (GET) .
For example, a review of three trials of CBT based
on a time-contingent approach found that despite
improvements reported in fatigue (and some other
selfreported measures), there was no increase in
activity levels as measured by actometers
compared with the controls .
One possible explanation for these paradoxical actigraphy results is activity substitution – participants reduce other activities in their lives to try to adhere to scheduled increases in specific exercises .
Alternatively, participants may simply not be
complying with scheduled exercise. The review does
not communicate the difficulties in finding an
intensity and quantity of exercise that can be
maintained given the fluctuations in the condition.
As the corresponding author found, even a
selfpaced exercise test of low intensity (mean: 46
Watts) lasting an average of just 5 min produced
an exacerbation of the CFS symptom complex .
Time-contingent approaches encourage patients to
maintain activity levels despite symptom increases,
but we do not have evidence participants comply
with such instructions.
Similarly, Van Cauwenbergh et al. recommend aiming
to gradually increase exercise up to 30 min
duration, but again we do not have either
objective, or even subjective, evidence that this
has regularly been achieved in trials.
Many CFS patients have reported being made worse
by exercise programs, sometimes long-term .
Given this information, the poor reporting of harms
in previous trials and the well-recognised problem
of potential bias with subjective and self-reported
measures, until we have more objective research
evidence regarding time-contingent approaches I
do not believe they can be recommended with
Conflicts of interest
I work in a voluntary (unpaid) capacity for the Irish
ME / CFS Association.
Irish ME / CFS Association, Dublin, Ireland (T.
Correspondence to: T. Kindlon, Irish ME / CFS
Association, PO Box 3075, Dublin 2, Ireland. Tel.:
0035312350965; fax: 0035314968360; e-mail:
email@example.com and firstname.lastname@example.org
Received 3 August 2012; accepted 13 August 2012
1 Van Cauwenbergh D, De Kooning M, Ickmans K,
Nijs J. How to exercise people with chronic fatigue
syndrome: evidence-based practice guidelines. Eur
J Clin Invest 2012; DOI: 10.1111/j.1365-2362.2012.
2 Kindlon T. Reporting of harms associated with
graded exercise therapy and cognitive behavioural
therapy in myalgic encephalomyelitis / chronic
fatigue syndrome. Bull IACFS /ME 2011;19:59–111,
http://bit.ly/VM3TDF - Last Accessed: August 3,
3 Wearden AJ, Dowrick C, Chew-Graham C, Bentall
RP, Morriss RK, Peters S et al. Nurse led, home
based self help treatment for patients in primary
care with chronic fatigue syndrome: randomised
controlled trial. BMJ 2010;340:c1777.
4 Wiborg JF, Knoop H, Stulemeijer M, Prins JB,
Bleijenberg G. How does cognitive behaviour
therapy reduce fatigue in patients with chronic
fatigue syndrome? The role of physical activity
Psychol Med 2010;40:1281–7
5 Van Oosterwijck J, Nijs J, Meeus M, Lefever I,
Huybrechts L, Lambrecht L et al. Pain inhibition and
postexertional malaise in myalgic encephalomyelitis
/ chronic fatigue syndrome: an experimental study.
J Intern Med 2010;268:265–78.