Category: Exercise

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

 

Time course of exercise induced alterations in daily activity in chronic fatigue syndrome

Abstract:

In a previous study we demonstrated that while people with CFS had lower daily activity levels than control subjects, they were able to increase daily activity via a daily walking program. We reanalyzed our data to determine the time course of activity changes during the walking program. Daily activity assessed via an accelometer worn at the hip was divided into sleep, active, and walking periods. Over the first 4-10 days of walking the subjects with CFS were able to reach the prescribed activity goals each day. After this time, walking and total activity counts decreased. Sedentary controls subjects were able to maintain their daily walking and total activity goals throughout the 4 weeks. Unlike our previous interpretation of the data, we feel this new analysis suggests that CFS patients may develop exercise intolerance as demonstrated by reduced total activity after 4-10 days. The inability to sustain target activity levels, associated with pronounced worsening of symptomology, suggests the subjects with CFS had reached their activity limit.

 

Source: Black CD, McCully KK. Time course of exercise induced alterations in daily activity in chronic fatigue syndrome. Dyn Med. 2005 Oct 28;4:10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1280928/ (Full article)

 

Impact of a maximal exercise test on symptoms and activity in chronic fatigue syndrome

Abstract:

OBJECTIVE: This study examined the effects of exercise on symptoms and activity in chronic fatigue syndrome (CFS).

METHODS: Twenty CFS patients and 20 neighborhood controls performed an incremental exercise test until exhaustion. Fatigue, muscle pain, minutes spent resting, and the level of physical activity were assessed with a self-observation list. Physical activity was assessed with an actometer as well. Data were obtained 3 days before the maximal exercise test (MET) up to 5 days thereafter.

RESULTS: For CFS patients, daily observed fatigue was increased up to 2 days after the exercise test. For controls, self-observed fatigue returned to baseline after 2 h. Both CFS patients and controls spent more minutes resting on the day before and on the day after the MET. For CFS patients, self-observed minutes resting increased on the day of the exercise test. For neither group, a decrease of actometer recorded or self-observed physical activity after exercise was found.

CONCLUSION: Fatigue in CFS patients increased after exercise, but the level of actual physical activity remained unchanged.

 

Source: Bazelmans E, Bleijenberg G, Voeten MJ, van der Meer JW, Folgering H. Impact of a maximal exercise test on symptoms and activity in chronic fatigue syndrome. J Psychosom Res. 2005 Oct;59(4):201-8. http://www.ncbi.nlm.nih.gov/pubmed/16223622

 

Exercise and cognitive performance in chronic fatigue syndrome

Abstract:

PURPOSE: To determine the effect of submaximal steady-state exercise on cognitive performance in patients with chronic fatigue syndrome (CFS) alone, CFS with comorbid fibromyalgia FM (CFS + FM), and sedentary healthy controls (CON).

METHODS: Twenty CFS-only patients, 19 CFS + FM, and 26 CON completed a battery of cognitive tests designed to assess speed of information processing, variability, and efficiency. Tests were performed at baseline, immediately before, and twice following 25 min of either cycle ergometry set at 40% of peak oxygen capacity or quiet rest.

RESULTS: There were no group differences in average percentage of peak oxygen consumption during exercise (CFS = 45%; CFS + FM = 47%; Control = 43%: P = 0.2). There were no significant effects of acute exercise on cognitive performance for any group. At baseline, one-way ANOVA indicated that CFS patients displayed deficits in speed of processing, performance variability, and task efficiency during several cognitive tests compared with healthy controls. However, the CFS + FM patients were not different than controls. Repeated measures ANOVA indicated that across all tests (pre- and postexercise) CFS, but not CFS + FM, were significantly less consistent (F2,59 = 3.7, P = 0.03) and less efficient (F2,59 = 4.6, P = 0.01) than controls.

CONCLUSION: CFS patients without comorbid FM exhibit subtle cognitive deficits in terms of speed, consistency, and efficiency that are not improved or exacerbated by light exercise. Importantly, our data suggest that CFS + FM patients do not exhibit cognitive deficits either pre- or postexercise. These results highlight the importance of disease heterogeneity in studies determining acute exercise and cognitive function in CFS.

 

Source: Cook DB, Nagelkirk PR, Peckerman A, Poluri A, Mores J, Natelson BH. Exercise and cognitive performance in chronic fatigue syndrome. Med Sci Sports Exerc. 2005 Sep;37(9):1460-7. http://www.ncbi.nlm.nih.gov/pubmed/16177595

 

A longitudinal study of physical activity and body mass index among persons with unexplained chronic fatigue

Abstract:

OBJECTIVE AND METHODS: A cohort of 100 patients with unexplained chronic fatigue (CF) was assessed longitudinally for 1.5 years to determine if physical activity (kcal expended), exercise capacity (VO(2)max), perceived exertion, and body mass index (BMI) changed over time and were associated with changes in CF-related clinical status.

RESULTS: BMI increased significantly over time but did not predict changes in clinical status. Increasing energy expenditure was associated with increasing vitality and decreasing CF symptom severity over time, and decreasing perceived exertion was associated with increasing physical functioning. However, increasing perceived exertion was also associated with increasing CF symptoms.

CONCLUSIONS: These data do not support models that posit associations between CF and deconditioning.

 

Source: Schmaling KB, Fiedelak JI, Bader J, Buchwald D. A longitudinal study of physical activity and body mass index among persons with unexplained chronic fatigue. J Psychosom Res. 2005 Apr;58(4):375-81. http://www.ncbi.nlm.nih.gov/pubmed/15992573

 

Is the chronic fatigue syndrome an exercise phobia? A case control study

Abstract:

OBJECTIVE: The aim of this study was to test whether patients with chronic fatigue syndrome (CFS) have an exercise phobia, by measuring anxiety-related physiological and psychological reactions to ordinary activity and exercise.

METHODS: Patients and healthy but sedentary controls were assessed over 8 h of an ordinary day, and before, during and after an incremental exercise test on a motorised treadmill. To avoid confounding effects, those with a comorbid psychiatric disorder were excluded. Heart rate, galvanic skin resistance (GSR) and the amount of activity undertaken were measured, along with state and trait measures of anxiety.

RESULTS: Patients with CFS were more fatigued and sleep disturbed than were the controls and noted greater effort during the exercise test. No statistically significant differences were found in either heart rate or GSR both during a normal day and before, during and after the exercise test. Patients with CFS were more symptomatically anxious at all times, but this did not increase with exercise.

CONCLUSION: The data suggest that CFS patients without a comorbid psychiatric disorder do not have an exercise phobia.

 

Source: Gallagher AM, Coldrick AR, Hedge B, Weir WR, White PD. Is the chronic fatigue syndrome an exercise phobia? A case control study. J Psychosom Res. 2005 Apr;58(4):367-73. http://www.ncbi.nlm.nih.gov/pubmed/15992572

 

Exercise capacity and immune function in male and female patients with chronic fatigue syndrome (CFS)

Abstract:

Hyperactivition of an unwanted cellular cascade by the immune-related protein RNase L has been linked to reduced exercise capacity in persons with chronic fatigue syndrome (CFS). This investigation compares exercise capacities of CFS patients with deregulation of the RNase L pathway and CFS patients with normal regulation, while controlling for potentially confounding gender effects.

Thirty-five male and seventy-one female CFS patients performed graded exercise tests to voluntary exhaustion. Measures of peak VO2, peak heart rate, body mass index, perceived exertion, and respiratory quotient were entered into a two-way factorial analysis with gender and immune status as independent variables. A significant multivariate main effect was found for immune status (p < 0.01), with no gender effect or interaction.

Follow-up analyses identified VO2(peak) as contributing most to the difference. These results implicate abnormal immune activity in the pathology of exercise intolerance in CFS and are consistent with a channelopathy involving oxidative stress and nitric oxide-related toxicity.

 

Source: Snell CR, Vanness JM, Strayer DR, Stevens SR. Exercise capacity and immune function in male and female patients with chronic fatigue syndrome (CFS). In Vivo. 2005 Mar-Apr;19(2):387-90. http://iv.iiarjournals.org/content/19/2/387.long (Full article)

 

Exercise responsive genes measured in peripheral blood of women with chronic fatigue syndrome and matched control subjects

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is defined by debilitating fatigue that is exacerbated by physical or mental exertion. To search for markers of CFS-associated post-exertional fatigue, we measured peripheral blood gene expression profiles of women with CFS and matched controls before and after exercise challenge.

RESULTS: Women with CFS and healthy, age-matched, sedentary controls were exercised on a stationary bicycle at 70% of their predicted maximum workload. Blood was obtained before and after the challenge, total RNA was extracted from mononuclear cells, and signal intensity of the labeled cDNA hybridized to a 3800-gene oligonucleotide microarray was measured. We identified differences in gene expression among and between subject groups before and after exercise challenge and evaluated differences in terms of Gene Ontology categories. Exercise-responsive genes differed between CFS patients and controls. These were in genes classified in chromatin and nucleosome assembly, cytoplasmic vesicles, membrane transport, and G protein-coupled receptor ontologies. Differences in ion transport and ion channel activity were evident at baseline and were exaggerated after exercise, as evidenced by greater numbers of differentially expressed genes in these molecular functions.

CONCLUSION: These results highlight the potential use of an exercise challenge combined with microarray gene expression analysis in identifying gene ontologies associated with CFS.

 

Source: Whistler T, Jones JF, Unger ER, Vernon SD. Exercise responsive genes measured in peripheral blood of women with chronic fatigue syndrome and matched control subjects. BMC Physiol. 2005 Mar 24;5(1):5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1079885/ (Full article)