Volume 44 Number 4 2007
Pages 553 — 560

Abstract - Comparison of two exercise testing protocols in patients with chronic fatigue syndrome

Jo Nijs, PhD, PT;1-2* Kim Zwinnen, PT;1 Romain Meeusen, PhD;1 Bas de Geus, MSc;1 Kenny De Meirleir, PhD1

1Department of Human Physiology, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; 2Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, University College Antwerp, Antwerp, Belgium

Abstract — This study examined whether a linear exercise stress-testing protocol generated different peak exercise performance variables than a stepwise exercise testing protocol in patients with chronic fatigue syndrome (CFS). We conducted a comparative study with patients randomly allocated to one of two exercise testing protocols. Twenty-eight women with CFS completed two self-reported measures (the CFS Symptom List and the CFS Activities and Participation Questionnaire) and then performed until exhaustion either the linear or the stepwise exercise testing protocol with continuous monitoring of physiological variables (heart rate and oxygen uptake). At baseline, we found no significant differences in demographic features and health status between groups (p > 0.05). Based on ratio peak workload/peak oxygen uptake, mechanical efficiency was lower among the subjects performing the stepwise protocol (p = 0.002). When we analyzed the mean linear regression slope values between oxygen uptake and workload from each subject's minute-by-minute exercise data points, we found that mechanical efficiency was lower among the subjects performing the stepwise protocol (p = 0.039). Apart from mechanical efficiency, we found no differences in exercise performance data between groups (p > 0.05). Our results suggest that the difference between linear and stepwise exercise protocols cannot account for all discrepancies of previous studies on exercise performance data in women with CFS, but they do suggest that the nature of the exercise testing protocol influences mechanical efficiency in these patients. Further study is warranted.

Key words: assessment, cardiopulmonary exercise testing, chronic fatigue syndrome, exercise capacity, exercise performance, exercise physiology, fibromyalgia, measurement, mechanical efficacy, oxygen uptake.

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