Objective: To examine the feasibility and efficacy of The Switch intervention in individuals reporting idiopathic chronic fatigue (self-reported diagnosis of Myalgic encephalomyelitis (ME)/ chronic fatigue syndrome (CFS) or long COVID) and to inform a clinical trial with power calculations. Methods: Of 127 individuals, 104 (81.8%) met the inclusion criteria (self-reporting CFS/ME [n = 75] or long-COVID [n = 29]; aged 16 + who completed at least one Switch session). The 12-item Short-Form (SF-12) and Visual analogue scales (VAS) were completed pre-intervention, and 2-and 12-month post-intervention. Results: One individual withdrew from the intervention. At least 77% of measures were completed at each assessment. All SF-12 scales except for social functioning improved significantly to 2months (range p < .001-.001). Significant improvements continued to 12 months for Role Limitations-Physical (p = .005) and Emotional Functioning (p = .02). Format (zoom vs face-toface) did not impact change (p > .05). A conservative power calculation suggests 36 participants would be required for a clinical trial. Conclusions: The Switch shows promise as a feasible and effective intervention for those with idiopathic chronic fatigue. A randomised controlled trial with a small number of participants with verified diagnoses and more targeted outcome measures is the next step in establishing its effectiveness.
Background:Fatigue is one of the most prevalent and disabling symptoms of multiple sclerosis (MS), frequently showing weak correlation with physical disability or MRI lesion burden. Central activation models link fatigue to dysfunction of brainstem arousal pathways, particularly the Ascending Reticular Activating System (ARAS). Because vertical saccades are generated in the mesencephalon and interact with these arousal networks, they may provide an objective marker of central fatigue. Objectives:To examine the relationship between vertical saccadic parameters and fatigue severity in MS, adjusting for cognitive impairment and affective symptoms. Results:Forty-four patients were included (61.4% women; mean age 49.0 ± 9.9 years; median EDSS 2.0). Fatigue severity was inversely associated with vertical saccadic peak velocity, most prominently for upward movements (r = -0.45, p < 0.01). In multivariable models adjusted for age, sex, cognition, lesion burden, depression, and anxiety, slower upward vertical peak velocity independently predicted greater fatigue severity (β = -0.0068; 95% CI -0.0129 to -0.0008; p = 0.028). This association remained statistically significant after additional adjustment for disease phenotype (p = 0.037), infratentorial lesion involvement (p = 0.030), and in a sensitivity analysis excluding interferon-β-treated patients (p = 0.036). Conclusions:Higher fatigue severity was independently associated with slower upward vertical saccadic peak velocity, across all sensitivity analyses. These findings suggest that vertical saccadic dynamics may represent a promising objective correlate of central fatigue and support a pathophysiological link with mesencephalic arousal network dysfunction in MS.
Background People living with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) often use pacing with a heart-rate monitor (HRM) to manage their activity intensities to minimise time spent over their anaerobic threshold; however, there is little research related to their experiences of this approach.Objective To explore the experiences of people with ME/CFS of pacing with an HRM.Methods 488 people with ME/CFS completed an online international survey, and 27 agreed to online follow-up semi-structured interviews. The open answers from the survey and the data from the interviews were analysed using reflective thematic analysis.Results 87% of the survey participants and 88% of the interviewees were female. 49% of the survey participants and 44% of the interviewees were between 35 and 50 years. Their ME/CFS severity ranged from mild to severe. Some themes matched the questions: Benefits, Negatives, Support and Ideal Design, and some themes emerged from the data: Barriers, Body awareness/Intuition, Acceptance and Recommendations.Conclusions This study produced further insights into pacing with an HRM not previously published related to benefits, ideal design and support. New themes were also identified: Body awareness/Intuition, Barriers, Acceptance and Recommendations. The majority of people with ME/CFS in this study felt that pacing with an HRM is a useful management tool, but randomised controlled trials are needed to determine who benefits and identify guidelines to minimise the negatives and reduce the barriers for people with ME/CFS.
Background: Fatigue is a complex phenomenon that presents persistent challenges for research and clinical care across multiple conditions. Objective: To explore development of an integrative theoretical framework linking lived experience, underlying mechanisms, and the design and evaluation of interventions. Methods: We conducted systematic scoping reviews to identify (i) systematic and narrative reviews of mechanisms or pathways of fatigue across clinical conditions, and (ii) systematic reviews and recent randomised controlled trials of interventions addressing fatigue. These reviews informed four consensus workshops with researchers, clinicians, and individuals with lived experience of fatigue that examined: (1) the meaning and evaluation of fatigue across conditions; (2) mechanisms and pathways; (3) evidence for outcomes and novel interventions; and (4) consensus development and program theory generation. Key findings: We present a summary of the discussions across the workshops and highlight the challenges that remain in evaluating the utility of an integrative theoretical framework. Substantial conceptual ambiguity was identified in how fatigue is defined and how mechanisms, pathways, and interventions are categorised. Inconsistent terminology, measurement approaches, and theoretical specification limit synthesis across conditions, and the current evidence base remains insufficiently articulated to support a coherent cross-condition account. Conclusion: Critical gaps remain in the use of common language, outcome measures, and theory-informed approaches to intervention development. Addressing these foundational limitations is necessary to determine whether an integrative framework for fatigue can be constructed, and whether this may support knowledge translation across diagnostic boundaries and hypothesis-driven research that is responsive to stakeholder priorities and delivers meaningful clinical benefit.
Objective: The purpose of this study was to identify potential phenotypic and biological factors that relate to directional changes in subjective feelings of mental and physical energy and fatigue during exercise-heat stress. Methods: Fifteen subjects (female = 6; 29 +/- 9 years; 71 +/- 14 kg) completed 90 min of cycling in the heat with (euhydration) or without fluid (dehydration). Subjective feelings of mental and physical energy and fatigue were measured using visual analog scales, and subjects were bifurcated based on the directionality of mood. Changes in mood were correlated with baseline phenotypic characteristics and biofluid composition. Results: Subjective feelings of mental (median change: 60.5 (hypohydrated) vs. 18.0 (euhydrated), p = 0.03) and physical fatigue (77.0 (hypohydrated) vs. 57.0 (euhydrated), p < 0.01) were greater post-exercise with dehydration, while feelings of mental (-27.0 (hypohydrated) vs. -18.5 (euhydrated), p = 0.17) and physical energy (-47.0 (hypohydrated) vs. -44.0 (euhydrated), p = 0.39) were not different compared to euhydration. Higher body mass index (p = 0.07), fat-free mass (0.03), and a more coordinated cardiorespiratory system (p < 0.01) were related to a decrease in mental energy and increased mental fatigue. Changes in blood carbon dioxide (p = 0.02) were greater in subjects who reported an increase in mental energy, while subjects who reported an increase in mental fatigue had lower decreases in blood chloride (p = 0.04). Subjects who reported an increased physical energy had a lower decrease in hemoglobin (p = 0.04). Conclusions: Our findings support previous work suggesting baseline characteristics and blood biomarkers may be associated with mood states.
Background Chronic fatigue (CF) is increasingly prevalent, yet its role as an independent risk factor for cerebrovascular and neurodegenerative diseases remains underexplored. Objective This study aimed to prospectively assess the association between CF and the risks of Parkinson's disease (PD), Alzheimer's disease (AD), cerebral infarction (CI), and all-cause mortality (ACM). Methods We utilized data from 167,098 UK Biobank participants (aged 40-69) with baseline information on CF (>= 6 months). Cox proportional hazards models with three tiers of covariate adjustment (demographics, lifestyle, comorbidities) were used to examine associations with incident PD, AD, CI, and ACM. Fine-Gray competing risk models accounting for death were also employed for PD, AD, and CI. Results CF was independently associated with significantly increased risks of PD (fully-adjusted HR = 3.02, 95% CI = 2.42-3.76, p < 0.0001), AD (HR = 1.68, 1.21-2.34, p = 0.002), CI (HR = 1.19, 1.02-1.39, p = 0.027), and ACM (HR = 1.86, 1.73-2.00, p < 0.0001). Competing risk analyses confirmed robustness (e.g. for PD: sHR = 2.97, p < 0.0001). Conclusions Chronic fatigue is an independent risk factor for developing PD, AD, CI, and for ACM. Assessment of CF may help identify high-risk populations for targeted prevention.
Background/ObjectiveWorking with children and young people (CYP), their parents and health professionals, we have co-produced the first patient-reported outcome measure, specific to CYP with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): the Paediatric Outcome Measure for ME (POMME). A two-stage psychometric evaluation is described.MethodsTwo field tests were conducted across two specialist ME/CFS services for CYP. In FT1, participants completed a 71-item, long-form POMME. Both classical test theory and modern psychometrics (Rasch) informed item reduction. The short-form POMME and additional PROMs were completed in FT2. Psychometric evaluations were repeated to inform data quality, internal consistency and validity.ResultsFT1 data analysis (n = 229) informed removal of 50 items, producing a 21-item POMME. Two items were re-introduced to enhance face validity. The 23-item POMME was completed in FT2 (n = 163). Data analysis informed the removal of two items, producing a three-domain, 21-item POMME: symptoms and cognition (6 items); physical activities and hobbies (6 items); and emotions and self-esteem (9 items).ConclusionsPOMME is a short, high-quality and acceptable measure suitable for the assessment of the physical, cognitive and emotional impact of ME/CFS in CYP. Whilst the data quality, reliability and validity of the measure are confirmed, further research is required to confirm measurement responsiveness.Key messagesDeveloped in collaboration with children and young people with ME/CFS, the POMME is a high-quality, relevant and acceptable patient-reported outcome measure (PROM) suitable for the assessment of the physical, cognitive and emotional impact of ME/CFS.
BackgroundVarious chronic health conditions are associated with household vulnerability to food insecurity. There is limited evidence regarding the prevalence of food insecurity or the experiences and challenges related to nutrition and food access among people living with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long Covid (LC) in Aotearoa New Zealand.MethodsAdults were recruited between June and September 2025 from online communities, support networks and primary care providers to complete an anonymous, online survey. Food insecurity was defined as 'sometimes' or 'never' being able to afford to eat properly, or 'sometimes' or 'always' having food run out, eating less, eating less variety due to cost, relying on others for food or using food grants/banks. Descriptive results were reported as percentages; multivariable risk ratios were estimated from generalised linear models. Quotes from open-ended questions were used to illustrate the quantitative findings.ResultsAmong 333 respondents, half (50%) had experienced food insecurity in the past 12 months. There was an inverse-J shape association between food insecurity and disease severity. Younger respondents were more likely to face food insecurity than older respondents. Beyond financial constraints, reported challenges to adequate nutrition included physical limitations affecting going shopping, receiving online deliveries and preparing meals.ConclusionFindings support the need to recognise ME/CFS and LC as disabilities for the purposes of social service and income support provision, which could relieve some of the financial pressures on patients. We also recommend that GPs routinely screen for food insecurity among people with ME/CFS or LC.
Background Brain information processing deteriorates as cortical neurons gradually transition from a rested state into fatigue. Subjectively, fatigue is experienced as a state of weariness, tiredness, or lack of energy that reduces the ability to work safely and effectively. Objective In this theoretical paper, we pinpoint the physical origin of brain fatigue in the gradual deterioration of biochemical reaction quotients and transmembrane ion concentration gradients, which increase neuronal excitability and decrease the signal-to-noise ratio in the brain cortex. Methods Brain performance in a rested state versus fatigue is examined by well-established, data-driven computer models for energy transport inside protein alpha-helices in the presence of thermal noise for different ATP energy states or for pyramidal neuron firing of action potentials under electric stimulation in a rested membrane state versus fatigue. Results We found that reduced Gibbs free energy supply from ATP hydrolysis impairs the cooperative effect between amide I excitons propagating inside protein alpha-helices, with resulting decreased thermal stability of molecular solitons. Concurrent changes in Nernst reversal potentials for Na+ or K+ ions further led to neuronal hyperexcitability and a higher risk of neuronal depolarization block during mental fatigue. Conclusions Detailed computational modeling showed that inefficient protein function due to diminished ATP energy status, alters the electrophysiological properties of individual neurons, thereby impairing their information processing capacity for the proper execution of cognitive tasks. Scheduling practices aimed at intermittent recovery of the rested brain state during intellectually challenging work could protect physical and mental wellbeing, prevent burnout, and enhance long-term productivity.
BackgroundFatiguing conditions such as myalgic encephalomyelitis/ chronic fatigue syndrome and post-COVID condition affect millions globally, presenting challenges for diagnosis and management due to their complex, multisystemic nature. Post-exertional malaise (PEM) is a key symptom of fatiguing conditions that involves a severe worsening of symptoms after physical or cognitive exertion.ObjectivesThis theoretical paper proposes a PEM-informed physiological decision-making framework that reconceptualizes PEM as a manifestation of impaired physiological recovery rather than solely a subjective symptom response. Drawing on evidence from serial cardiopulmonary exercise testing, the framework integrates reproducible abnormalities in respiratory variables during exercise as objective indicators of impaired metabolic recovery.MethodsThe authors synthesize current evidence on the use of serial cardiopulmonary exercise tests to objectively assess physiological markers of PEM across two consecutive days. Protocol recommendations are provided. The framework further outlines how exercise test-derived metrics can be translated into rehabilitation decision-making to guide pacing, intensity limits, and progression while minimizing symptom exacerbation.ConclusionsThe authors provide an evidence-based approach to activity management aimed at reducing harm, avoiding the push - crash cycle, and supporting functional stability and quality of life in individuals living with fatiguing conditions. When done correctly, exercise testing and therapy can be a safe and valuable tool to enhance recovery and quality of life in individuals living with fatiguing conditions, including those experiencing PEM.
Objective: The study aims to examine the relationship between occupational noise exposure and the levels of physical, mental, and emotional fatigue among speedboat crew members.Methods: A cross-sectional study was conducted among speedboat crew members in Tarakan, North Kalimantan, Indonesia on November 2024. This study involves two categories of ship personnel as samples, namely, crew members and captains were 87 crews were enrolled in this study. We calculated using Spearman's rho models to analysed the data.Results: The study found that occupational noise levels on speedboats ranged from 77.9 to 100.9 dB(A), with one vessel exceeding the safe exposure threshold. The level of fatigue among the respondents is mostly in the low category (69% - 74.7%). Occupational noise aboard speedboats is a significant contributor to physical (r = .715, p = .040) and mental fatigue (r = .839, p = .022).Conclusion: The results of the statistical test indicate that, besides the main research variable, other confounding variables correlate with the fatigue levels of the crew, such as age, educational background, and working period. While overall fatigue levels were low, the study highlights the need to address noise exposure and other correlated factors to safeguard seafarers well-being.
Objective:This study characterized physical activity levels in people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MECFS) before and after a 2-day cardiopulmonary exercise test (CPET) protocol. Activity levels of people with MECFS were compared to sedentary controls and separated into day and night activity to elucidate circadian differences.Methods:People with MECFS (n = 58) and sedentary controls (CTRL; n = 41) completed a 2-day CPET. For six days prior to testing and 10 days following testing, participants wore an ActiGraph GT3X-BT accelerometer on the dominant wrist to track daily activity. Physical activity intensity was separated into sedentary, light, and moderate/vigorous zones based on accelerometry cut-off points. Linear mixed effects models were used to compare differences in activity levels between groups.Results:People with MECFS spent significantly more time in sedentary activity and less time in light and moderate/vigorous activity compared to the control group. These differences persisted when further separated into daytime and nighttime hours.Conclusion:Those with MECFS spend a larger portion of their day in sedentary activities compared to sedentary controls. MECFS also spend comparatively less time in light-vigorous activities throughout the day, suggesting that people with MECFS are overall generally much less physically active than sedentary otherwise healthy individuals.
Objective: The main purpose of this study is to determine the fatigue symptoms of pilots and to show how these symptoms trend according to flight types.Methods: Using a quantitative research design, the study collected data from 161 pilots working at three airlines in various regions of Turkey using a survey. Cross-tabulation analyses were conducted to examine the trend of fatigue symptoms across flight types; correlation analysis was performed to investigate the relationships between variables; and the Mann-Whitney U test was conducted to assess whether safety behaviour differs in terms of perceived adequacy of fatigue strategies.Findings: The results revealed that pilots most frequently experienced symptoms of sleeplessness and reduction of attention and concentration, with short-medium-haul pilots experiencing these symptoms more frequently depending on the type of flight. In addition to these findings, significant differences were found in safety behaviour averages scores depending on whether they perceived the organizations where pilots work's fatigue management strategies as adequate.Conclusion: Pilot fatigue has been found to manifest through a variety of symptoms, including sleeplessness, reduced attention and lack of concentration, small mistakes, difficulty perceiving messages from the tower, difficulty in decision-making, delays in response times, hormonal disorders, irritability, and decreased social communication, mini drops asleep. These symptoms are known to adversely affect critical human factor competencies. Given this established relationship, developing fatigue management strategies regarding flight planning are considered to be of great importance in mitigating such risks.
ObjectiveCognitive capacity tests can measure cognitive fatigability (CF) in persons with multiple sclerosis (pwMS). This study investigated test-retest reliability of CF measures using Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT).MethodsCF index (CFI%) comparing the last and first thirds and delta scores of SDMT and PASAT were assessed in 49 pwMS (EDSS:3-6.5) and 23 healthy controls. Tests were performed twice 5-7 days apart.ResultsBoth groups showed a performance decline (-2 to -21%). CFI and delta showed poor reliability in both groups (ICC range = 0.04-0.36).ConclusionsCF measures exhibited low reliability in pwMS.
Objective: This study evaluated the psychometric properties of the Scales for Outcomes in Parkinson's Disease - Sleep Scale (SCOPA-Sleep) in a sample of patients with fibromyalgia syndrome (FMS), and examined the unique and interactive associations between sleep problems, daytime fatigue, and quality of life. Method: A total of 79 adults diagnosed with FMS according to the 2010 American College of Rheumatology criteria completed measures assessing sleep problems, daytime fatigue (SCOPA-Sleep), and health-related quality of life (EuroQOL-5D). Exploratory factor analysis (EFA) and internal consistency analyses assessed the dimensionality and reliability of the SCOPA-Sleep. Multiple linear regression examined confounding and moderation effects of sleep problems and fatigue on quality of life, controlling for sociodemographic variables. Results: EFA supported a two-factor structure of the SCOPA-Sleep reflecting distinct subscales for nighttime sleep problems and daytime fatigue. The subscales were uncorrelated, and both demonstrated strong internal consistency (alpha = .87 and .84, respectively). Regression analyses revealed that daytime fatigue was not significantly associated with quality of life after adjusting for covariates. However, sleep problems were a significant predictor of reduced quality of life (beta = - .33, p < .01). No significant interaction between sleep problems and fatigue was observed. Conclusions: The SCOPA-Sleep may be a useful brief screening tool for sleep-related impairments in clinical FMS assessment. However, given the relatively small and homogeneous sample (predominantly middle-aged women not currently employed), the generalizability of these findings is limited. Future research should replicate these results in larger and more diverse FMS populations.
