Category: Exercise

Sense of effort during a fatiguing exercise protocol in chronic fatigue syndrome

Abstract:

The purpose of this study was to determine whether chronic fatigue syndrome (CFS) subjects would produce greater force production in their matching limb during a fatiguing contralateral limb-matching task of the elbow flexors, compared with healthy, matched controls.

Eight CFS subjects and 8 healthy, matched control subjects participated in a fatiguing task that consisted of intermittent submaximal contractions (30% maximal voluntary contraction) of the nondominant arm performed over a 45 min duration. Each minute, the subject attempted to match the force of the nondominant arm with their dominant arm (without visual feedback for the dominant arm).

Results showed that average matching force and ratings of perceived effort values were significantly higher in the CFS group during the fatiguing task (P = 0.04, P = 0.02, respectively). This study demonstrated objectively that CFS subjects experienced a greater sense of effort in the elbow flexors while performing a fatiguing task.

 

Source: Wallman KE, Sacco P. Sense of effort during a fatiguing exercise protocol in chronic fatigue syndrome. Res Sports Med. 2007 Jan-Mar;15(1):47-59. https://www.ncbi.nlm.nih.gov/pubmed/17365951

 

Exercise testing in children and adolescents with chronic fatigue syndrome

Abstract:

The objective of this study was to evaluate exercise capacity in children and adolescents diagnosed with Chronic Fatigue Syndrome (CFS). We examined 20 patients (12 girls and 8 boys; mean age 14.9 +/- 3.7 years) diagnosed with CFS.

Exercise capacity was measured using a maximal exercise test on a bicycle ergometer and an expired gas analysis system. Fatigue was assessed using a questionnaire and a daily activity diary was used to describe activities for three days. Z-scores were calculated using age- and sex-matched reference values. Z-scores in children and adolescents with CFS were – 0.33 +/- 1.0 (p = 0.17) for peak oxygen uptake, – 1.13 +/- 1.41 (p = 0.002) for relative peak oxygen uptake [ml/kg/min] and – 0.93 +/- 1.29 (p = 0.07) for maximal work load. Both heart rate and blood pressure at peak performance were significantly reduced compared to reference values.

Fatigue levels were significantly positively associated with age and negatively with blood pressure at peak exercise (p < 0.05). In conclusion maximum exercise testing was feasible in young people with CFS. Maximal exercise capacity was only reduced in a minority of the patients and was related to current physical activity levels.

 

Source: Takken T, Henneken T, van de Putte E, Helders P, Engelbert R. Exercise testing in children and adolescents with chronic fatigue syndrome. Int J Sports Med. 2007 Jul;28(7):580-4. Epub 2007 Mar 15. https://www.ncbi.nlm.nih.gov/pubmed/17357961

 

Can submaximal exercise variables predict peak exercise performance in women with chronic fatigue syndrome?

Abstract:

This study aimed at examining whether physiological exercise variables at the submaximal level, defined as 75% of the age-predicted target heart rate, are able to predict peak exercise performance in women with chronic fatigue syndrome (CFS) (n=222). Subjects performed a bicycle ergometric test against a graded increase in workload until exhaustion with continuous monitoring of electrocardiographic and ventilatory variables. Oxygen uptake at the submaximal level (VO2SUBMAX) correlated strongly with peak oxygen uptake (VO2PEAK) (r=0.70). For the prediction of VO2PEAK, linear regression analysis determined the line of best fit as: VO2PEAK=0.95xVO2SUBMAX+372.3. Using this equation, the mean error in the prediction was 14.6+/-11.2% (range 0.1-63.7%). It is concluded that the prediction of VO2PEAK based on VO2SUBMAX might be useful for analyzing group differences or treatment effects but not for individual (clinical) purposes.

Source: Nijs J, Demol S, Wallman K. Can submaximal exercise variables predict peak exercise performance in women with chronic fatigue syndrome? Arch Med Res. 2007 Apr;38(3):350-3. Epub 2007 Jan 30. https://www.ncbi.nlm.nih.gov/pubmed/17350488

The influence of aerobic fitness and fibromyalgia on cardiorespiratory and perceptual responses to exercise in patients with chronic fatigue syndrome

Abstract:

OBJECTIVE: To investigate cardiorespiratory and perceptual responses to exercise in patients with chronic fatigue syndrome (CFS), accounting for comorbid fibromyalgia (FM) and controlling for aerobic fitness.

METHODS: Twenty-nine patients with CFS only, 23 patients with CFS plus FM, and 32 controls completed an incremental bicycle test to exhaustion. Cardiorespiratory and perceptual responses were measured. Results were determined for the entire sample and for 18 subjects from each group matched for peak oxygen consumption.

RESULTS: In the overall sample, there were no significant differences in cardiorespiratory parameters between the CFS only group and the controls. However, the CFS plus FM group exhibited lower ventilation, lower end-tidal CO2, and higher ventilatory equivalent of carbon dioxide compared with controls, and slower increases in heart rate compared with both patients with CFS only and controls. Peak oxygen consumption, ventilation, and workload were lower in the CFS plus FM group. Subjects in both the CFS only group and the CFS plus FM group rated exercise as more effortful than did controls. Patients with CFS plus FM rated exercise as significantly more painful than did patients with CFS only or controls. In the subgroups matched for aerobic fitness, there were no significant differences among the groups for any measured cardiorespiratory response, but perceptual differences in the CFS plus FM group remained.

CONCLUSION: With matching for aerobic fitness, cardiorespiratory responses to exercise in patients with CFS only and CFS plus FM are not different from those in sedentary healthy subjects. While CFS patients with comorbid FM perceive exercise as more effortful and painful than do controls, those with CFS alone do not. These results suggest that aerobic fitness and a concurrent diagnosis of FM are likely explanations for currently conflicting data and challenge ideas implicating metabolic disease in the pathogenesis of CFS.

 

Source: Cook DB, Nagelkirk PR, Poluri A, Mores J, Natelson BH. The influence of aerobic fitness and fibromyalgia on cardiorespiratory and perceptual responses to exercise in patients with chronic fatigue syndrome. Arthritis Rheum. 2006 Oct;54(10):3351-62. https://www.ncbi.nlm.nih.gov/pubmed/17009309

 

Submaximal aerobic exercise with mechanical vibrations improves the functional status of patients with chronic fatigue syndrome

Abstract:

AIM: Chronic fatigue syndrome (CFS) is an illness characterised by disabling fatigue of uncertain aetiology and other nonspecific symptoms. Typically CFS patients complain of a severe fatigue made worse by exercise, with a consistent reduction of working activity. A physical deconditioning could explain CFS features as well as a neuromuscular dysfunction, of central or peripheric origin.

METHODS: Ten CFS patients were enrolled in a protocol of a rehabilitative treatment over a six-month period: they underwent a submaximal and predominantly aerobic exercise with a reduced O2 consumption using a Galileo 2000 system that provides mechanical vibrations characterised by sinusoid vertical sollecitations. Before and after such treatment, all patients underwent a pressure pain thresholds profile, an evaluation of physical and psychosocial parameters using the visual analogue scale (VAS) of Scott-Huskisson, and a muscle performance analysis by the CIBEX 6000 dynamometer.

RESULTS: After the six-month period of study there was an overall improvement of the above described parameters as compared to the basal determinations.

CONCLUSION: We conclude that the rehabilitative exertion provides an useful treatment for CFS patients particularly to realize an effective training of the explosive strength.

 

Source: Saggini R, Vecchiet J, Iezzi S, Racciatti D, Affaitati G, Bellomo RG, Pizzigallo E. Submaximal aerobic exercise with mechanical vibrations improves the functional status of patients with chronic fatigue syndrome. Eura Medicophys. 2006 Jun;42(2):97-102. http://www.minervamedica.it/en/journals/europa-medicophysica/article.php?cod=R33Y2006N02A0097 (Full article)

 

 

How relevant are exercise capacity measures for evaluating treatment effects in chronic fatigue syndrome? Results from a prospective, multidisciplinary outcome study

Abstract:

OBJECTIVE: To evaluate the outcome of a multidisciplinary treatment programme for patients with chronic fatigue syndrome, including health-related quality of life (HRQoL) and psychosocial variables, and exercise capacity measures.

DESIGN: A six-month prospective outcome study.

SETTING: University outpatient rehabilitation clinic; group setting.

SUBJECTS: One hundred and sixteen women fulfilling chronic fatigue syndrome criteria.

INTERVENTIONS: Cognitive behaviourally and graded exercise-based strategies; emphasis on adaptive lifestyle changes.

MEASURES: Short Form General Health Survey (SF-36); Symptom Checklist (SCL-90); Causal Attribution List (CAL); Self-Efficacy Scale (SE); maximum progressive bicycle ergometer test with respiratory gas analysis; and isokinetic leg strength test, before and after treatment.

RESULTS: The total group significantly improved on nearly all reported HRQoL/psychosocial variables. Changes in exercise capacity measures were rather modest and did not correlate or only weakly correlated with HRQoL/psychosocial variables. Subgroup analyses indicated that less fit patients improved significantly more on exercise capacity measures than their more fit counterparts. Patients who were fitter at baseline scored better on pretreatment HRQoL/psychosocial variables, but both subgroups improved similarly on these variables.

CONCLUSIONS: Health-related quality of life and psychosocial functioning in patients with chronic fatigue syndrome improves after a six-month cognitive behaviourally and graded exercise-based multidisciplinary treatment programme. Increase in exercise capacity measures is not a necessary condition for reported improvements, except for less fit patients.

 

Source: Pardaens K, Haagdorens L, Van Wambeke P, Van den Broeck A, Van Houdenhove B. How relevant are exercise capacity measures for evaluating treatment effects in chronic fatigue syndrome? Results from a prospective, multidisciplinary outcome study. Clin Rehabil. 2006 Jan;20(1):56-66. https://www.ncbi.nlm.nih.gov/pubmed/16502751

 

Reliability of physiological, psychological, and cognitive variables in chronic fatigue syndrome

Abstract:

The purpose of this study was to assess the reliability of specific physiological, psychological, and cognitive variables in 31 chronic fatigue syndrome (CFS) subjects and 31 matched control subjects. All variables were assessed weekly over a 4-week period and reliability was determined using an intraclass correlation coefficient (ICC). Results ranged from moderately to highly reliable for all variables assessed, except for mental and physical fatigue, which were of questionable reliability in both groups (ICC = 0.61 and 0.65, respectively, for the CFS group; 0.62 and 0.52 for the control group).

A Pearson product-moment correlation analysis that compared exercise performance with all psychological variables assessed, demonstrated a significant relationship between exercise performance and depression (r = .41, P = .02) in week 3 only, suggesting minimal association between objective performance and psychological responses. These correlation results support a central, as opposed to a peripheral, basis to the sensation of fatigue in CFS.

 

Source: Wallman KE, Morton AR, Goodman C, Grove R. Reliability of physiological, psychological, and cognitive variables in chronic fatigue syndrome. Res Sports Med. 2005 Jul-Sep;13(3):231-41. http://www.ncbi.nlm.nih.gov/pubmed/16392538

 

Employment status in chronic fatigue syndrome. A cross-sectional study examining the value of exercise testing and self-reported measures for the assessment of employment status

Abstract:

OBJECTIVE: To examine the value of exercise testing and self-reported disability for the assessment of employment status in patients with chronic fatigue syndrome.

DESIGN: Cross-sectional observational study.

SETTING: A university-based chronic fatigue clinic.

SUBJECTS: Fifty-four consecutive, Flemish, employed (not self-employed) chronic fatigue syndrome patients (49/54 female).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Participants were questioned about their current and premorbid employment status, filled in the Chronic Fatigue Syndrome Activities and Participation Questionnaire (CFS-APQ), the Medical Outcomes Short Form 36 Health Status Survey (SF-36), and performed a maximal exercise test on a bicycle ergometer with continuous monitoring of cardiorespiratory variables.

RESULTS: A significant association was observed between the current employment rate and two SF-36 subscales (i.e., role limitations due to physical functioning and social functioning; rho = 0.39 and 0.35 respectively) (n = 54). Analysing only the female chronic fatigue syndrome patients (n = 49), the current employment rate correlated significantly with the peak workload (rho = 0.38).

CONCLUSIONS: The associations between either exercise testing or self-reported disability and employment status are too weak to predict employment status.

 

Source: Nijs J, Van de Putte K, Louckx F, De Meirleir K. Employment status in chronic fatigue syndrome. A cross-sectional study examining the value of exercise testing and self-reported measures for the assessment of employment status. Clin Rehabil. 2005 Dec;19(8):895-9. http://www.ncbi.nlm.nih.gov/pubmed/16323389

 

Reliability of physiological, psychological and cognitive variables in chronic fatigue syndrome and the role of graded exercise

Abstract:

The objective of this study was to assess variability in symptoms and physical capabilities in chronic fatigue syndrome (CFS) participants both before and after a graded exercise intervention. Sixty-one CFS subjects participated in a 12-week randomized controlled trial of either graded exercise (n =32) or relaxation/stretching therapy (n = 29). Specific physiological, psychological and cognitive variables were assessed once weekly over a four-week period both prior to and after the intervention period. All scores were assessed for reliability using an intraclass correlation coefficient (ICC).

Apart from mental and physical fatigue, baseline ICC scores for all variables assessed were moderately to highly reliable, indicating minimal variability. Baseline scores for mental and physical fatigue were of questionable reliability, indicating a fluctuating nature to these symptoms (R1 = 0.64 and 0.60, respectively). Variability in scores for mental fatigue was reduced after graded exercise to an acceptable classification (R1 = 0.76). Results from this study support a variable nature to the symptoms of mental and physical fatigue only.

Consequently, in order to more accurately report the nature of mental and physical fatigue in CFS, future studies should consider using repeated-measures analysis when assessing these symptoms. Graded exercise resulted in the reclassification of scores for mental fatigue from questionable to acceptable reliability.

Key Points: Chronic fatigue syndrome sufferers often report a fluctuating nature to their symptoms and physical capabilities.Weekly assessment over a four-week period of psychological, physiological and cognitive variables demonstrated that only mental and physical fatigues were of questionable reliability.A 12-week graded exercise intervention resulted in the improvement of ICC scores for mental fatigue to that of acceptable reliability.

 

Source: Wallman KE, Morton AR, Goodman C, Grove R. Reliability of physiological, psychological and cognitive variables in chronic fatigue syndrome and the role of graded exercise. J Sports Sci Med. 2005 Dec 1;4(4):463-71. eCollection 2005. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899663/ (Full article)

 

Chronic fatigue syndrome: exercise performance related to immune dysfunction

Abstract:

PURPOSE: To date, the exact cause of abnormal exercise response in chronic fatigue syndrome (CFS) remains to be revealed, but evidence addressing intracellular immune deregulation in CFS is growing. Therefore, the aim of this cross-sectional study was to examine the interactions between several intracellular immune variables and exercise performance in CFS patients.

METHODS: After venous blood sampling, subjects (16 CFS patients) performed a maximal exercise stress test on a bicycle ergometer with continuous monitoring of cardiorespiratory variables. The following immune variables were assessed: the ratio of 37 kDa Ribonuclease (RNase) L to the 83 kDa native RNase L (using a radiolabeled ligand/receptor assay), RNase L enzymatic activity (enzymatic assay), protein kinase R activity assay (comparison Western blot), elastase activity (enzymatic-colorimetric assay), the percent of monocytes, and nitric oxide determination (for monocytes and lymphocytes; flow cytometry, live cell assay).

RESULTS: Forward stepwise multiple regression analysis revealed 1) that elastase activity was the only factor related to the reduction in oxygen uptake at a respiratory exchange ratio (RER) of 1.0 (regression model: R = 0.53, F (1,14) = 15.5, P < 0.002; elastase activity P < 0.002); 2) that the protein kinase R activity was the principle factor related to the reduction in workload at RER = 1.0; and 3) that elastase activity was the principle factor related to the reduction in percent of target heart rate achieved.

CONCLUSION: These data provide evidence for an association between intracellular immune deregulation and exercise performance in patients with CFS. To establish a causal relationship, further study of these interactions using a prospective longitudinal design is required.

 

Source: Nijs J, Meeus M, McGregor NR, Meeusen R, de Schutter G, van Hoof E, de Meirleir K. Chronic fatigue syndrome: exercise performance related to immune dysfunction. Med Sci Sports Exerc. 2005 Oct;37(10):1647-54. http://www.ncbi.nlm.nih.gov/pubmed/16260962