(submitted) findings regarding exercise programs in CFS. TK]
http://www.bmj.com/cgi/eletters/339/oct13_1/b3410#224003
It is improbable that high intensity exercise reduces fatigue during
chemotherapy
30 October 2009
Martine M. Goedendorp,
psychologist/researcher
Expert Centre for Chronic Fatigue, Radboud University Nijmegen Medical
Centre,PO Box 9101,6500 HB,NL,
Marianne J. Heins, Hetty Prinsen, Hanneke W.M. van Laarhoven and Gijs
Bleijenberg.
Send response to journal:
Re: It is improbable that high intensity exercise reduces fatigue during
chemotherapy
With great interest we read the article of Adamsen et al. (2009)1 on a
multimodal group exercise intervention for patients undergoing chemotherapy.
The intervention consisted of high intensity and low intensity components
and, as described in the online trial registration, included four
components: a physical exercise, relaxation training, body awareness
training and massage. Two important issues raised our concern. First, the
effect of the intervention on fatigue is not clinically relevant. Second,
the suggestion that physical exercise reduced fatigue is not proven.
First, the results showed that the effect of the intervention on fatigue was
small. Although the estimated mean difference on fatigue was 6.6, the actual
difference was only 3.1. More importantly, both these differences on fatigue
did not reach the clinically relevant difference of 10 points, as was
estimated beforehand.
Although a small but significant effect on fatigue was found, the study did
not offer an explanation for this effect. Adamsen et al. (2009)1 suggested
reduced physical activity and muscular de-conditioning were causes for
fatigue, and that the improvement in vitality could be attributed to the
high intensity component. However, these assumptions were not tested in this
study. Therefore, no conclusions can be drawn about the relative effect of
the different components of the intervention on fatigue. A mediation
analysis could have clarified what caused the effect on fatigue.
In the past several studies have refuted the hypothesis that improving
physical condition, or increasing physical activity, leads to a reduction in
fatigue. In fact, the two exercise studies in breast cancer patients cited
by Adamsen et al. (2009)1 observed a significant improvement in physical
condition (12 minute walk test, and VO2-max) and muscular strength, but no
improvement in fatigue2 3.
Furthermore, there are several randomised controlled trials (RCT) in which
interventions proved to be effective for fatigue, without improving physical
condition or increasing physical activity. Our research group recently
studied the contribution of increasing physical activity in cognitive
behaviour therapy (CBT) in different samples. In these submitted studies no
support was found for the mediating role of physical activity in CBT for
fatigue in patients with chronic fatigue syndrome (CFS), cancer patients on
active treatment, and cancer survivors. In addition, Moss-Morris performed a
graded exercise RCT for CFS and found that not physical condition, but
symptom focusing mediated the improvement in fatigue4. From these studies it
can be concluded that it is possible to reduce fatigue without increasing
physical activity, and that the reduction in fatigue is probably caused by
other factors than an improvement in physical condition. For example,
improved self-esteem, group support or changes in cognitions may have
reduced the level of fatigue in the breast cancer patients who participated
in the multimodal high intensity exercise intervention during chemotherapy
by Adamsen et al. (2009).1 Therefore, it is too early to implement this
intensive intervention into the usual care for cancer patients.
Martine M. Goedendorp1, Marianne J. Heins1, Hetty Prinsen2, Hanneke W.M. van
Laarhoven2 and Gijs Bleijenberg1
1 Expert Centre for Chronic Fatigue, Radboud University Nijmegen Medical
Centre
2 Department of Medical Oncology, Radboud University Nijmegen Medical Centre
References
1. Adamsen L, Quist M, Andersen C, Moller T, Herrstedt J, Kronborg D, et al.
Effect of a multimodal high intensity exercise intervention in cancer
patients undergoing chemotherapy: randomised controlled trial. Bmj
2009;339:b3410.
2. Courneya KS, Segal RJ, Mackey JR, Gelmon K, Reid RD, Friedenreich CM, et
al. Effects of aerobic and resistance exercise in breast cancer patients
receiving adjuvant chemotherapy: a multicenter randomized controlled trial.
J Clin Oncol 2007;25(28):4396-404.
3. Mutrie N, Campbell AM, Whyte F, McConnachie A, Emslie C, Lee L, et al.
Benefits of supervised group exercise programme for women being treated for
early stage breast cancer: pragmatic randomised controlled trial. Bmj
2007;334(7592):517.
4. Moss-Morris R, Sharon C, Tobin R, Baldi JC. A randomized controlled
graded exercise trial for chronic fatigue syndrome: outcomes and mechanisms
of change. J Health Psychol 2005;10(2):245-59.
Competing interests: None declared
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