13 research outputs found

    Effect of the subjective intensity of fatigue and interoception on perceptual regulation and performance during sustained physical activity

    Get PDF
    BACKGROUND: The subjective experience of fatigue impairs an individual’s ability to sustain physical endurance performance. However, precise understanding of the specific role perceived fatigue plays in the central regulation of performance remains unclear. Here, we examined whether the subjective intensity of a perceived state of fatigue, pre-induced through prior upper body activity, differentially impacted performance and altered perceived effort and affect experienced during a sustained, isometric contraction in lower body. We also explored whether (cardiac) interoception predicted the intensity of experienced perceptual and affective responses and moderated the relationships between constructs during physical activity. METHODS: Using a repeated-measures study design, thirty male participants completed three experimental conditions, with the intensity of a pre-induced state of fatigue manipulated to evoke moderate (MOD), severe (SEV) and minimal (control; CON) intensity of perceptions prior to performance of the sustained contraction. RESULTS: Performance of the sustained contraction was significantly impaired under a perceived state of fatigue, with reductions of 10% and 14% observed in the MOD and SEV conditions, respectively. Performance impairment was accompanied by greater perceived effort and more negative affective valence reported during the contraction. However, effects were limited to comparisons to CON, with no difference evident between the two experimental trials (i.e. MOD vs. SEV). Individuals’ awareness of their accuracy in judging resting heartbeats was shown to predict the subjective intensity of fatigue experienced during the endurance task. However, interoception did not moderate the relationships evident between fatigue and both perceived effort and affective valence. CONCLUSIONS: A perceived state of fatigue limits endurance performance, influencing both how effortful activity is perceived to be and the affective experience of activity. Though awareness of interoceptive representations of bodily states may be important to the subjective experience of fatigue, interoception does not modulate the relationships between perceived fatigue and other perceptual (i.e. effort) and affective constructs

    Toward the unity of pathological and exertional fatigue: a predictive processing model

    Get PDF
    Fatigue is a common experience in both health and disease. Yet, pathological (i.e., prolonged or chronic) and transient (i.e., exertional) fatigue symptoms are traditionally considered distinct, compounding a separation between interested research fields within the study of fatigue. Within the clinical neurosciences, nascent frameworks position pathological fatigue as a product of inference derived through hierarchical predictive processing. The metacognitive theory of dyshomeostasis (Stephan et al., 2016) states that pathological fatigue emerges from the metacognitive mechanism in which the detection of persistent mismatches between prior interoceptive predictions and ascending sensory evidence (i.e., prediction error) signals low evidence for internal generative models, which undermine an agent’s feeling of mastery over the body and is thus experienced phenomenologically as fatigue. Although acute, transient subjective symptoms of exertional fatigue have also been associated with increasing interoceptive prediction error, the dynamic computations that underlie its development have not been clearly defined. Here, drawing on the metacognitive theory of dyshomeostasis, we extend this account to offer an explicit description of the development of fatigue during extended periods of (physical) exertion. Accordingly, it is proposed that a loss of certainty or confidence in control predictions in response to persistent detection of prediction error features as a common foundation for the conscious experience of both pathological and nonpathological fatigue

    The LUCID study: living with ulcerative colitis; identifying the socioeconomic burden in Europe

    Get PDF
    Background Ulcerative colitis (UC) is an inflammatory bowel disease with increasing prevalence worldwide. Current treatment strategies place considerable economic and humanistic burdens on patients. The aim of this study was to determine the socioeconomic burden of UC in adult patients in European countries in a real-world setting. Methods In this retrospective, cross-sectional and observational pan-European study, patients with moderate or severe UC were assigned to ARM 1 and patients who had moderate or severe UC but achieved mild or remission status 12 months before index date (or clinical consultation date), were assigned to ARM 2. Clinical and medical resource use data were collected via electronic case report forms, and data on non-medical and indirect costs, and health-related quality of life (HRQoL) were collected via patient and public involvement and engagement (PPIE) questionnaires. Per-patient annual total costs per ARM and per country were calculated using the collated resource use in the last 12 months (between the start of the documentation period and patient consultation or index date) and country specific unit costs. Quality of life was described by arm and by country. Results In the physician-reported eCRF population (n = 2966), the mean annual direct medical cost was €4065 in ARM 1 (n = 1835) and €2935 in ARM 2 (n = 1131). In the PPIE population (ARM 1, n = 1001; ARM 2, n = 647), mean annual direct cost was €4526 in ARM 1 and €3057 in ARM 2, mean annual direct non-medical cost was €1162 in ARM 1 and €1002 in ARM 2, mean annual indirect cost was €3098 in ARM 1 and €2309 ARM 2, and mean annual total cost was in €8787 in ARM 1 and €6368 in ARM 2. HRQoL scores showed moderate to high burden of UC in both groups. Conclusions The cost and HRQoL burden were high in patients in both ARM 1 and ARM 2 indicating unmet needs in the UC active population

    Interactions between perceptions of fatigue, effort, and affect decrease knee extensor endurance performance following upper body motor activity, independent of changes in neuromuscular function

    No full text
    Prior exercise has previously been shown to impair subsequent endurance performance in non‐activated muscles. Declines in the neuromuscular function and altered perceptual/affective responses offer possible mechanisms through which endurance performance may be limited in these remote muscle groups. We thus conducted two experiments to better understand these performance‐limiting mechanisms. In the first experiment, we examined the effect of prior handgrip exercise on the behavioral, perceptual, and affective responses to a sustained, sub‐maximal contraction of the knee extensors. In the second experiment, transcranial magnetic stimulation was used to assess the neuromuscular function of the knee extensors before and after the handgrip exercise. The results of the first experiment demonstrated prior handgrip exercise increased the perceptions of effort and reduced affective valence during the subsequent knee extensor endurance exercise. Both effort and affect were associated with endurance performance. Subjective ratings of fatigue were also increased by the preceding handgrip exercise but were not directly related to knee extensor endurance performance. However, perceptions of fatigue were correlated with heightened effort perception and reduced affect during the knee extensor contraction. In the second experiment, prior handgrip exercise did not significantly alter the neuromuscular function of the knee extensors. The findings of the present study indicate that motor performance in the lower limbs following demanding exercise in the upper body appears to be regulated by complex, cognitive‐emotional interactions, which may emerge independent of altered neuromuscular function. Subjective fatigue states are implicated in the control of perceptual and affective processes responsible for the regulation of endurance performance
    corecore