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PubMed2003

Muscle fatigue and fatigue-related biomechanical changes during a cyclic lifting task.

STUDY DESIGN: Electromyographic and biomechanical methods were utilized to investigate correlations between indexes of localized muscle fatigue and changes in the kinematics and kinetics of motion during a cyclic lifting task. SUMMARY OF BACKGROUND DATA: Recent advances in time-frequency analysis procedures for electromyographicic signal processing provide a new way of studying localized muscle fatigue during dynamic contractions. These methods provide a means to investigate fatigue-related functional impairments in patients with low back pain. OBJECTIVES: To study the relationship between localized muscle fatigue and the biomechanics of lifting and lowering a weighted box. Fatigue-related changes in the electromyographicic signal of trunk and limb muscles were evaluated and compared to kinematic and kinetic measures in order to determine whether lifting strategy is modified with fatigue. METHODS: A total of 14 healthy male subjects (26 +/- 5 years) cyclically lifted and lowered a 13 kg box (12 lifts/min) for 4.5 minutes. A 5-second static maximum lifting task was included immediately before and after the cyclic lifting task to measure changes in lifting strength and static electromyographicic fatigue indexes. Electromyographic signals from 14 muscle sites (including paravertebral and limb muscles) were measured. Changes in the electromyographicic Instantaneous Median Frequency, a fatigue index, were computed using time-frequency analysis methods. This index was compared with more standardized measures of fatigue, such as those based on electromyographicic median frequency acquired during a static trunk extension test, subjective fatigue measures, and maximal static lifting strength. Biomechanical measures were gathered using a motion analysis system to study kinematic and kinetic changes during the lifting task. RESULTS: During the cyclic lifting task, the electromyographic Instantaneous Median Frequency significantly decreased over time in the paravertebral muscles, but not in the limb muscles. Paravertebral electromyographicic Instantaneous Median Frequency changes were consistent with self-reports of fatigue as well as decreases in trunk extension strength. The magnitude of muscle-specific changes in electromyographicic Instantaneous Median Frequency was not significantly correlated with electromyographicic median frequency changes from the static trunk extension task. The load of the box relative to the maximal static lifting strength significantly affected the electromyographicic Instantaneous Median Frequency changes of paravertebral back muscles. Significant changes with fatigue during the task were found in the angular displacements at the knee, hip, trunk, and elbow. These biomechanical changes were associated with increased peak torque and forces at the L4-L5 vertebral segment. CONCLUSIONS: Our results demonstrate correlation between localized muscle fatigue and biomechanical adaptations that occur during a cyclic lifting task. This new technique may provide researchers and clinicians with a means to investigate fatigue-related effects of repetitive work tasks or assessment procedures that might be useful in improving education, lifting ergonomy, and back school programs. Although both the dynamic and static tasks resulted in spectral shifts in the electromyographicic data, the fact that these methods led to different muscle-specific findings indicates that they should not be considered as equivalent assessment procedures.

Adult↗
PubMed2002

Patient-related barriers to fatigue communication: initial validation of the fatigue management barriers questionnaire.

Fatigue is a highly prevalent and distressing symptom of cancer and its treatment. However, cancer patients often fail to communicate with their oncologists about fatigue. In this study, we attempted to identify the patient-related barriers to communication about fatigue, as cited by patients. Two hundred patients were sampled across the Community Cancer Care, Inc. (CCC) network of Indiana using the Cancer Behavior Inventory-Brief scale (CBI-B), the Zung Self-Rating Depression Scale (ZSDS), the Functional Assessment of Cancer Inventory-Fatigue scale (FACT-F), and the Fatigue Management Barriers Questionnaire (FMBQ), a questionnaire devised by experts in the field of cancer-related fatigue. There were no significant correlations between the instrument scores and demographic variables. Scores on the instruments did not differ significantly based on whether the patient was from a rural or urban site. One hundred thirty-two patients (66%) reported that they had never spoken to their doctor about fatigue. The most frequently reported reasons for this lack of patient communication about fatigue included the doctor's failure to offer interventions (47%), patients' lack of awareness of effective treatments for fatigue (43%), a desire on the patient's part to treat fatigue without medications (40%), and not wanting to complain to the doctor (28%). Patients reported that medical staff offered a mean of 11.63 recommendations for dealing with fatigue. The FMBQ was found to correlate significantly with self-efficacy (CBI-B, r = -0.20, P < 0.01) and correlate weakly with the number of recommendations made (r = -0.15, P < 0.05). The FMBQ was noted to have acceptable internal consistency (alpha = 0.88) and validity and may prove to be a useful instrument for understanding why patients do not communicate about fatigue. Multiple barriers contribute to why cancer patients do not comment about fatigue but may be overcome if physicians screen and assess for this symptom.

Aged↗
PubMed2003

Fatigue, burnout, and chronic fatigue syndrome among employees on sick leave: do attributions make the difference?

BACKGROUND: Persistent fatigue among employees, burnout, and chronic fatigue syndrome (CFS) are three fatigue conditions that share some characteristics in theory. However, these conditions have not been compared in empirical research, despite conceptual similarities. METHODS: This cross sectional study aimed to investigate relations between persistent fatigue, burnout, and CFS by describing the clinical features of a sample of 151 fatigued employees on sick leave. Using validated instruments, subgroups based on research criteria for CFS and burnout within the sample of fatigued employees and a reference group of 97 diagnosed CFS patients were compared. Analyses of covariance were performed. RESULTS: A total of 66 (43.7%) fatigued employees met research criteria for CFS (except symptom criteria) and 76 (50.3%) met research criteria for burnout. "CFS-like employees" (fatigued employees who met CFS criteria) reported stronger somatic attributions than "non-CFS-like employees". Burnt out CFS-like employees were more depressed and distressed than CFS-like employees who were not burnt out. Burnout cases among the non-CFS-like employees had stronger psychological attributions than fatigued employees who were not burnt out. Compared to diagnosed CFS patients, CFS-like employees merely had a shorter duration of fatigue complaints. Burnt out CFS-like employees had stronger psychological attributions and were more distressed than CFS patients. CONCLUSIONS: Fatigued employees shared many important characteristics with CFS patients, regardless of burnout status, and many fatigued employees met CFS criteria and/or burnout criteria. Differences however concerned the causal attributions that were made. This raises questions about the role of causal attributions: are they modified by fatigue complaints or do they determine illness outcome?

Adult↗
PubMed2006

Low frequency fatigue in human quadriceps is fatigue dependent and not task dependent.

It is well accepted that a low intensity/long duration isometric contraction induces more low frequency fatigue (LFF) compared to a high-intensity/short-duration contraction. However, previous reports examined the intensity/duration of the contraction but did not control the level of fatigue when concluding fatigue is task dependent. The purpose of this study was to determine whether a long duration/low intensity fatiguing contraction would induce greater LFF than a short duration/high-intensity contraction when the quadriceps muscle was fatigued to similar levels. Eighteen healthy male subjects performed quadriceps contractions sustained at 35% and 65% of maximal voluntary contraction (MVC) on separate days, until the tasks induced a similar amount of fatigue (force generating capacity=45% MVC). Double pulse torque to single pulse torque ratio (D/S ratio) was obtained before, immediately and 5min after fatigue along with the electromyographic (EMG) signal from vastus medialis (VM) and rectus femoris (RF). The D/S ratio significantly (p<0.05) increased by 8.7+/-8.5% (mean+/-SD) and 10.2+/-9.2% after 35% and 65% tasks, respectively, and remained elevated 5min into recovery; however, there was no significant difference in ratio between the two sessions immediately or 5min post-fatigue (p>0.05) even though the endurance time for the 35% fatigue task (124+/-39.68s) was significantly longer (p=0.05) than that of the 65% task (63+/-17.73s). EMG amplitude and median power frequency (MPF) analysis also did not reveal any significant differences between these two sessions after fatigue. These findings indicate that LFF fatigue is fatigue dependent as well as task intensity/duration dependent. These findings assist us in understanding task dependency and muscle fatigue.

Adult↗
PubMed2006

Multidimensional measurement of fatigue in advanced cancer patients in palliative care: an application of the multidimensional fatigue inventory.

To investigate the level, dimensionality, and correlates associated with fatigue in patients receiving specialist palliative care, 278 advanced cancer patients referred to a department of palliative medicine during a 2-year period were asked to complete the Multidimensional Fatigue Inventory (MFI-20), a self-assessment questionnaire measuring five dimensions of fatigue, and the Hospital Anxiety and Depression Scale. Of 267 eligible patients, 130 (49%) participated. Mean fatigue scores (0-100 scale) were very high, especially for general fatigue (81), physical fatigue (87), and reduced activity (85). Only some of the MFI-20 subscales were significantly correlated. Fatigue was not correlated with sociodemographic factors. Depressed patients had higher scores on all five subscales except physical fatigue. Anxious patients had higher levels on the mental fatigue subscale only. The variation in fatigue explained by depression varied markedly (4%-31%) among subscales. Fatigue levels were very high in this population. The lack of significant correlation between some subscales indicates that they measure different aspects of fatigue. This is also supported by the differences in associations between fatigue subscales and depression and anxiety.

Adult↗
PubMed1997

Implications of task-induced fatigue effects for in-vehicle countermeasures to driver fatigue.

Two driving simulator studies are reported which investigate the variation of fatigue effects with task demands and provide recommendations for system design to counteract driver fatigue. Two opposing explanations of the interactive effects of task demands and fatigue were examined. One explanation is that fatigue drains attentional resources, so that detrimental effects of fatigue on performance are accentuated when task demands increase. The alternative explanation is that fatigue disrupts matching of effort to task demands, such that the fatigued driver fails to regulate effort effectively when the task appears easy. In both studies, drivers performed both a fatiguing drive, in the first part of which they were required to perform a secondary detection task, and a control drive with no additional secondary task. In the last part of both drives, drivers were required to detect movement in pedestrian stimuli presented on both sides of the road. Vehicle control and steering movements were logged throughout both drives. The results are consistent with dynamic models of stress and sustained performance which suggest that fatigue may impair adaptation to conditions of underload, but are inconsistent with the attentional resource explanation. These task-specific fatigue effects have important implications for in-vehicle countermeasures to driver fatigue. Current approaches to the implementation of such devices fail to reflect the task-specific nature of fatigue effects. Fatigue-monitoring devices may only be valid in certain driving environments or contexts. Hence, it may be necessary to integrate performance-based feedback monitoring information with route and traffic density information from navigation systems.

Adaptation, Psychological↗
PubMed1998

Fatigue in multiple sclerosis: interrelations between fatigue complaints, cerebral MRI abnormalities and neurological disability.

Although fatigue is a frequent complaint of patients with multiple sclerosis (MS), little is known about the origins of multiple-sclerosis-associated fatigue. Our primary focus was to study if the extent of cerebral abnormalities, as shown on magnetic resonance imaging (MRI), had any relation with the frequency and intensity of fatigue complaints of patients with a definite diagnosis of MS. Fatigue severity was rated by the patients with the use of a 2-week diary and a fatigue questionnaire, while conventional T1- and T2-weighted MRI provided several measures for cerebral abnormalities. In total, 72% of 45 patients reported to be seriously fatigued at least several times a week over the last 3-month period. Fatigue severity was not related to the total extent of cerebral abnormalities, or to MRI-based atrophy measures. Regional lesion load did not differ between fatigued and non-fatigued subjects. Although neurological disability, as measured by the Expanded Disability Status Scale (EDSS) and Neurological Rating Scale (NRS), did correlate significantly with most MRI measures, it showed no relation with fatigue severity. Neurological progression rates and number of exacerbations in the 2-year period prior to assessment were not significantly associated with the fatigue measures. Therefore, our findings suggest that differences in levels of self-reported fatigue in patients with multiple sclerosis cannot merely be explained by the degree of clinical disease activity, neurological disability or the extent of MRI abnormalities. These results are compared to other research findings and the possible role of alternative factors influencing fatigue in multiple sclerosis are discussed.

Adult↗
PubMed2003

Exercise reduces fatigue in chronic fatigued Hodgkins disease survivors--results from a pilot study.

The aims of this pilot study were to compare aerobic capacity in non-fatigued and fatigued Hodgkin's disease survivors (HDS) and to assess the feasibility of an exercise-programme and its effects upon fatigue, physical functioning and aerobic capacity in chronic fatigued HDS. 53 HDS (85%) of originally 62 survivors treated at the Trondheim University Hospital in the period 1987-1997 completed a questionnaire including the Fatigue Questionnaire (FQ). 18 subjects were identified with chronic fatigue. 15 non-fatigued HDS matched for gender and age were drawn as controls. Both groups were invited to medical examination and exercise tests. All 15 fifteen non-fatigued HDS showed up to the medical examination. 12 of the 18 patients with chronic fatigue completed the tests and nine agreed to enter a home-based exercise intervention. Outcome measures were aerobic capacity, fatigue and physical functioning. No significant difference in aerobic capacity was found between the chronic fatigued HDS and the controls. Fatigue, physical functioning and maximal aerobic capacity were significantly improved after the intervention. Aerobic exercise had a positive effect upon chronic fatigue in HDS. However, the study is a pilot study and needs confirmation in a larger group of subjects. The intervention was well accepted, and the majority of the patients adhered to the programme.

Adult↗
PubMed2001

[Measuring fatigue of cancer patients in the German-speaking region: development of the Fatigue Assessment Questionnaire].

UNLABELLED: Fatigue is recognised as one of the most frequent and distressing symptoms of patients with cancer. Whilst causal relationships mainly remain unclear, researchers meanwhile acknowledge its multidimensional nature. Causes and manifestations are complex and multifaceted and therefore, measurement in the past has been difficult. In recent years, some instruments have been developed in the English language. It is the aim of this article to describe the development of a new fatigue measurement instrument in the German language, the Fatigue Assessment Questionnaire. The following steps are described: 1. Concept analysis, 2. Identification of measurement criteria, 3. Comparison of these criteria with those described in the literature available, 4. Construction of a measurement scale, 5. Testing the new instrument, 6. Use of the instrument in a large study population. Steps 5 and 6 primarily deal with validity and reliability testing while step 6 also tests the hypothesis that patients with some types and stages of cancer suffer more from distressing fatigue than patients with other types and stages. CONCLUSION: Validity of the measurement items in the Fatigue Assessment Questionnaire was supported by the fact that they were derived from qualitative interviews with cancer patients. The first test with 77 cancer patients and 77 healthy individuals led to small adaptations and the following study, including 592 cancer patients, supported the reliability and validity of the Fatigue Assessment Questionnaire. It was able to distinguish between different populations. Factor analyses supported the earlier generated model of physical, affective and cognitive fatigue. Internal consistency of the questionnaire was supported by the Alpha Coefficient 0.90 (Cronbach). A difference was found in physical tiredness for patients with different types of cancer (p = 0.008) but this was not the case for affective and cognitive tiredness. More fatigue feelings were experienced by cancer patients with advanced disease than by patients in remission and this was true for physical fatigue (p = 0.0001), affective fatigue (p = 0.01), cognitive fatigue (p = 0.02) as well as for fatigue intensity (p = 0.0001) and distress (p = 0.0001). This group of patients also experienced significantly higher levels of depression and anxiety (p = 0.0001). The Fatigue Assessment Questionnaire, developed in the German speaking part of Switzerland, can be used for further activities in the field of quality of life and nursing care in oncology. The instrument and a proposed scoring system are published as an addendum to this article.

Adolescent↗
PubMed2000

Impact of cancer-related fatigue on the lives of patients: new findings from the Fatigue Coalition.

PURPOSE: This survey was designed to confirm the prevalence and duration of fatigue in the cancer population and to assess its physical, mental, social, and economic impacts on the lives of patients and caregivers. Patients and Methods. A 25-minute telephone interview was completed with 379 cancer patients having a prior history of chemotherapy. Patients were recruited from a sample of 6, 125 households in the United States identified as having a member with cancer. The median patient age was 62 years, and 79% of respondents were women. Patients reporting fatigue at least a few times a month were asked a series of questions to better describe their fatigue and its impact on quality of life. RESULTS: Seventy-six percent of patients experienced fatigue at least a few days each month during their most recent chemotherapy; 30% experienced fatigue on a daily basis. Ninety-one percent of those who experienced fatigue reported that it prevented a "normal" life, and 88% indicated that fatigue caused an alteration in their daily routine. Fatigue made it more difficult to participate in social activities and perform typical cognitive tasks. Of the 177 patients who were employed, 75% changed their employment status as a result of fatigue. Furthermore, 65% of patients indicated that their fatigue resulted in their caregivers taking at least one day (mean, 4.5 days) off work in a typical month. Physicians were the health care professionals most commonly consulted (79%) to discuss fatigue. Bed rest/ relaxation was the most common treatment recommendation (37%); 40% of patients were not offered any recommendations. CONCLUSIONS: Cancer-related fatigue is common among cancer patients who have received chemotherapy and results in substantial adverse physical, psychosocial, and economic consequences for both patients and caregivers. Given the impact of fatigue, treatment options should be routinely considered in the care of patients with cancer.

Adult↗
PubMed2006

Cognitive dysfunction relates to subjective report of mental fatigue in patients with chronic fatigue syndrome.

Patients with chronic fatigue syndrome (CFS) frequently complain of cognitive dysfunction. However, evidence of cognitive impairment in CFS patients has been found in some, but not other, studies. This heterogeneity in findings may stem from the relative presence of mental fatigue in the patient populations examined. The present study assessed this possibility in a population-based sample of CFS patients. In all, 43 patients with CFS defined by the criteria of the 1994 research case definition using measurements recommended by the 2003 International CFS Study Group, and 53 age-, sex-, and race/ethnicity-matched nonfatigued subjects were included in the study. Mental fatigue was assessed using the mental fatigue subscale of the multidimensional fatigue inventory. Cognitive function was evaluated using an automated battery of computerized tests (Cambridge neuropsychological test automated battery (CANTAB)) that assessed psychomotor function, planning and problem-solving abilities, and memory and attentional performance. CFS patients with significant complaints of mental fatigue (score of mental fatigue 2 standard deviations above the mean of nonfatigued subjects) exhibited significant impairment in the spatial working memory and sustained attention (rapid visual information processing) tasks when compared to CFS patients with low complaints of mental fatigue and nonfatigued subjects. In CFS patients with significant mental fatigue, sustained attention performance was impaired only in the final stages of the test, indicating greater cognitive fatigability in these patients. CFS patients with low mental fatigue displayed performance comparable to nonfatigued subjects on all tests of the CANTAB battery. These findings show strong concordance between subjective complaints of mental fatigue and objective measurement of cognitive impairment in CFS patients and suggest that mental fatigue is an important component of CFS-related cognitive dysfunction.

Cognition Disorders↗
PubMed2002

Fatigue in cancer patients compared with fatigue in the general United States population.

BACKGROUND: Although fatigue is a common symptom among cancer patients, it is also a common experience in the general, healthy population. Its universality has made it difficult to appreciate whether the fatigue experienced by patients with cancer is distinguishable from the fatigue experienced by the general population. Because the etiology of fatigue is multifactorial, it also has been difficult to appreciate fully the relative contribution of anemia to cancer-related fatigue. METHODS: To address this issue, responses to a brief, standardized set of 13 questions from the Functional Assessment of Chronic Illness Therapy (FACIT) Measurement System were compared across three groups: anemic cancer patients (n = 2369 patients), nonanemic cancer patients (n = 113 patients), and the general United States population (n = 1010 persons). RESULTS: Fatigue scores of the anemic cancer patients (at both baseline and upon completion of anemia therapy) were significantly worse compared with the scores of nonanemic cancer patients that, in turn, were worse compared with the scores of the general United States population (P < 0.001). Score distributions were quite distinct for these three groups. Within the group of anemic cancer patients, the degree of anemia (mild, moderate, or severe) also was predictive of the degree of fatigue (P < 0.001), although the distributions were not dramatically distinct. CONCLUSIONS: Although anemia is clearly a factor that contributes to the severity of disease-related fatigue among cancer patients, hemoglobin levels explain only part of the difference compared with fatigue among the general United States population. The distinct distributions of fatigue scores of anemic cancer patients compared with the general United States population and the substantial sample sizes of these two groups enabled a discriminant analysis approach that allowed the differentiation of anemic cancer patients from the general population with high sensitivity (0.92) and reasonable specificity (0.69). Thus, although fatigue is a symptom most anyone can relate to, the fatigue of cancer patients, particularly those who are anemic, is decidedly worse. Interventions targeting this common and life-disrupting symptom likely would be of considerable value to patients with cancer.

Anemia↗
PubMed2004

Effects of lumbar extensor fatigue and fatigue rate on postural sway.

Falls from heights resulting from a loss of balance are a major concern in the occupational setting. Previous studies have documented a deleterious effect of lower extremity fatigue on balance. The purpose of this study was to investigate the effect of lumbar extensor fatigue on balance during quiet standing. Additionally, the effects of fatigue rate on balance and balance recovery rate were assessed. Eight center-of-pressure-based measures of postural sway were collected from 13 participants, both before and after a protocol that fatigued the lumbar extensors to 60% of their unfatigued maximum voluntary exertion force. In addition, postural sway was measured for 30 min after the fatiguing protocol, at 5-min intervals, to quantify balance recovery rate during recovery from fatigue. Two different fatigue rates were achieved by fatiguing participants over either 10 min or 90 min. Results show an increase up to 58% in time-domain postural sway measures with lumbar extensor fatigue, but no change in frequency-domain measures. Fatigue rate did not affect the magnitude of these postural sway increases, nor did it affect the rate of balance recovery following fatigue. Statistical power for the latter result, however, was low. These results show that lumbar extensor fatigue increases postural sway and may contribute to fall-from-height accidents.

Adult↗
PubMed2000

Coping strategies in twins with chronic fatigue and chronic fatigue syndrome.

OBJECTIVES: Individuals with chronic fatigue and chronic fatigue syndrome (CFS) face debilitating symptoms as well as stressful life situations that may result from their condition. The goal of this study was to examine the coping strategies used by fatigue-discordant twin pairs. METHODS: We utilized a co-twin design to assess how twin pairs discordant for chronic fatigue and CFS cope with stress. All twin pairs were administered the Revised Ways of Coping Checklist. RESULTS: Overall, the pattern of coping strategies was similar for fatigued and non-fatigued twins. However, twins with chronic fatigue or CFS utilized more avoidance strategies than their non-fatigued counterparts; those with chronic fatigue also used more avoidance relative to problem-focused coping than their co-twins. CONCLUSIONS: These results suggest that while fatigue-discordant twins generally exhibit similar behavior patterns in order to cope with stress, there may be an association between fatigue and avoidance coping. Future research should focus on the role of avoidance and its relationship to fatiguing illnesses.

Adaptation, Psychological↗
PubMed1998

The persistence of fatigue in chronic fatigue syndrome and multiple sclerosis: development of a model.

The cause of chronic fatigue syndrome (CFS) is unknown. With respect to factors perpetuating fatigue, on the other hand, a model has been postulated in the literature in which behavioral, cognitive, and affective factors play a role in perpetuating fatigue. In the present study, this hypothesized model was tested on patients with CFS and on fatigued patients with multiple sclerosis (MS). The model was formulated in terms of cause-and-effect relationships and an integral test of this model was performed by the statistical technique, "structural equation modeling," in 51 patients with chronic fatigue syndrome and 50 patients with multiple sclerosis matched for age, gender, and education. Attributing complaints to a somatic cause produced low levels of physical activity, which in turn had a causal effect on fatigue severity. Depression had to be deleted from the model. Sense of control over symptoms and focusing on bodily symptoms each had a direct causal effect on fatigue. The model showed an excellent fit for CFS patients, but was rejected for MS patients. Therefore, a new model for MS patients had to be developed in which sense of control had a causal effect on fatigue. In the MS model, no causal relationship was found between the physical state as measured by the Expanded Disability Status Score (EDSS) and fatigue or functional impairment. The present study shows that cognitive and behavioral factors are involved in the persistence of fatigue. Treatment should be directed at these factors. The processes involved in the subjective experience of fatigue in CFS were different from the processes related to fatigue in MS.

Adult↗
PubMed2005

A comparison between long-term survivors of Hodgkin's disease and their siblings on fatigue level and factors predicting for increased fatigue.

PURPOSE: To compare the level of fatigue in survivors of Hodgkin's disease and their siblings, and to explore factors associated with increased fatigue. METHODS: Survivors of Hodgkin's disease 5 years or more from diagnosis and their siblings completed a questionnaire study. Fatigue level was measured using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) instrument, with lower scores reflecting increased fatigue. Multiple regression models were used to identify factors associated with fatigue level in the two populations. RESULTS: Five hundred and eleven survivors (median age 44 years; range 16-82) and 224 siblings (median age 44 years; range 16-79) returned the completed questionnaire. The response rates were 61% and 58%, respectively. Compared with siblings, survivors were significantly more likely to report the presence of cardiac disease (26% versus 16%; P = 0.001) and hypothyroidism (65% versus 3%; P <0.001), and had a significantly lower mean FACIT-F score (40.7 and 42.2; P = 0.05). On multivariable analysis, factors significantly associated with increased fatigue in survivors were reports of cardiac disease (P <0.001), psychiatric condition (P <0.001), history of tobacco use (P = 0.004) and low exercise frequency (P = 0.03). For siblings, the only independent factor associated with increased fatigue was low exercise frequency (P = 0.03). CONCLUSIONS: Survivors of Hodgkin's disease were more fatigued than their siblings. The difference was modest but statistically significant. The significant association between fatigue and cardiac disease suggests the importance of screening for underlying cardiac dysfunction in survivors with symptoms of fatigue. The association between fatigue and smoking history may be due to exacerbation of late medical complications of Hodgkin's disease by tobacco use.

Adolescent↗
PubMed2005

Development and validation of a scale to measure work-related fatigue and recovery: the Occupational Fatigue Exhaustion/Recovery Scale (OFER).

OBJECTIVE: Various empirical studies link persistent failure to recover from acute fatigue to the evolution of chronic fatigue. However, existing fatigue measurement scales do not tend to distinguish between acute and chronic fatigue elements well, and none include a measure of effective recovery from fatigue. METHODS: The 15 item Occupational Fatigue Exhaustion Recovery (OFER) scale has been developed and validated in three study populations specifically to measure work-related fatigue. RESULTS: The OFER scale possesses robust, gender-bias free psychometric characteristics. Its three subscales identify and distinguish between chronic work-related fatigue traits, acute end-of-shift states and effective fatigue recovery between shifts. CONCLUSION: These studies confirm the mediating role of intershift-shift recovery in the evolution of adaptive end-of-shift fatigue states to maladaptive persistent fatigue traits. The OFER scale is suggested as a potentially valuable new tool for use in work-related fatigue research.

Adult↗
PubMed2006

Supraspinal fatigue does not explain the sex difference in muscle fatigue of maximal contractions.

Young women are less fatigable than young men for maximal and submaximal contractions, but the contribution of supraspinal fatigue to the sex difference is not known. This study used cortical stimulation to compare the magnitude of supraspinal fatigue during sustained isometric maximal voluntary contractions (MVCs) performed with the elbow flexor muscles of young men and women. Eight women (25.6 +/- 3.6 yr, mean +/- SD) and 9 men (25.4 +/- 3.8 yr) performed six sustained MVCs (22-s duration each, separated by 10 s). Before the fatiguing contractions, the men were stronger than the women (75.9 +/- 9.2 vs. 42.7 +/- 8.0 N.m; P < 0.05) in control MVCs. Voluntary activation measured with cortical stimulation before fatigue was similar for the men and women during the final control MVC (95.7 +/- 3.0 vs. 93.3 +/- 3.6%; P > 0.05) and at the start of the fatiguing task (P > 0.05). By the end of the six sustained fatiguing MVCs, the men exhibited greater absolute and relative reductions in torque (65 +/- 3% of initial MVC) than the women (52 +/- 9%; P < 0.05). The increments in torque (superimposed twitch) generated by motor cortex stimulation during each 22-s maximal effort increased with fatigue (P < 0.05). Superimposed twitches were similar for men and women throughout the fatiguing task (5.5 +/- 4.1 vs. 7.3 +/- 4.7%; P > 0.05), as well as in the last sustained contraction (7.8 +/- 5.9 vs. 10.5 +/- 5.5%) and in brief recovery MVCs. Voluntary activation determined using an estimated control twitch was similar for the men and women at the start of the sustained maximal contractions (91.4 +/- 7.4 vs. 90.4 +/- 6.8%, n = 13) and end of the sixth contraction (77.2 +/- 13.3% vs. 73.1 +/- 19.6%, n = 10). The increase in the area of the motor-evoked potential and duration of the silent period did not differ for men and women during the fatiguing task. However, estimated resting twitch amplitude and the peak rates of muscle relaxation showed greater relative reductions at the end of the fatiguing task for the men than the women. These results indicate that the sex difference in fatigue of the elbow flexor muscles is not explained by a difference in supraspinal fatigue in men and women but is largely due to a sex difference of mechanisms located within the elbow flexor muscles.

Adult↗