The fatigue illusion: the physical effects of mindlessness

The paper challenges mind/body dualism and the conventional view that fatigue is purely a somatic response to physiological depletion. Drawing on Langer’s mind/body unity theory, the authors hypothesize that perceived fatigue follows relative, proportional milestones within a task—fatigue start (FS) and fatigue peak (FP)—independent of absolute duration, intensity, or task type (physical vs. cognitive). This implies a “fatigue illusion,” shaped by premature cognitive commitments and teleoanticipation, which may limit human potential. The research aims to (1) demonstrate the proportional nature of fatigue milestones across tasks and populations, and (2) test whether perceptions of fatigue can be shifted through Langerian mindfulness, thereby offering individuals greater control over fatigue onset, peak, and experience. The work is positioned as contributing a novel metric for fatigue (timing and duration) and exploring the malleability of fatigue perceptions through socio-cognitive interventions.

Prior work conceptualizes fatigue as a conscious feeling arising from physiological deviations mapped against a homeostatic proto-Self (St. Clair Gibson et al., 2003), with expectations and prior experience influencing exertion via teleoanticipation (Hampson et al., 2001). Research often treats perceptions as separate from physiology (dualism), but fewer studies examine manipulating assumptions about fatigue. Langer’s socio-cognitive mindfulness framework emphasizes creating novelty and reappraising fixed categories, with applications in aging, disease, and mental health (Levy et al., 2001; Park et al., 2016; Carson & Langer, 2006). Evidence suggests perceptions are shapeable (Chanowitz & Langer, 1981; Stróżak, 2008). EEG studies indicate alpha power and entropy track mental workload and alertness (Käthner et al., 2014; Aminoff, 2012; Subramaniyam, 2018). Fatigue research has underemphasized duration as a dimension (DeLuca, 2005). This paper integrates these literatures to test whether fatigue milestones are relative and whether mindfulness-based strategies can modulate them.

A five-study program tested the fatigue illusion across contexts and assessed malleability via mindfulness constructs.

• Study 1 (Self-reports of Long-Distance Travel): 28 college students (M_age=19.07) recalled their longest trip (≥3 h) in past 3 months and indicated FS and FP as percentages of total trip (0–100% slider), plus fatigue level (1–10). Travel mode and role (driver/passenger) recorded. Retrospective survey via Qualtrics (~15 min). Data deposited: https://doi.org/10.7910/DVN/CBOYWO.
• Study 2 (Counting Task with EEG): 294 students randomly assigned to 200-, 400-, or 600-integer counting tasks (multiples of 3) within 15 minutes (fixed time; varied cognitive load). Post-task, participants reported FS, FP (0–100%), fatigue levels at FS/FP (1–10), perceived timing of most mistakes, and desire to discontinue (timing in quintiles). EEG recorded via Neurosky Mindwave (512 Hz raw; 1 Hz eSense) focusing on alpha power and multiscale entropy (MSE) across eight evenly divided task stages. Data deposited: https://doi.org/10.7910/DVN/CBOYWO.
• Study 3 (Ballerina Study): 12 professional ballet dancers (4 male, 8 female) from Hessen State Ballet held developpé à la seconde at 90° for gender-specific short (SH) or long (LH) durations (from pilot): females 42 or 48 s; males 70 or 80 s. Participants reported FS and FP (in seconds) which were standardized to percentage of individual hold time; fatigue levels (1–5 Likert). PANAS-SF measured state affect post-task. Three blinded expert observers (professional dancers) rated videoed FS and FP (in seconds) without knowing assigned durations; inter-rater reliability via ICC. Data: https://doi.org/10.7910/DVN/CBOYWO.
• Study 4 (Hand-grip Task with Trait Measures): 91 male students randomized to: No-goal (hold as long as possible), or fixed 120 s, 180 s, or 240 s. FS/FP recorded as percentages of actual hold time; fatigue levels at FS/FP (1–10). Trait measures: Langer Mindfulness Scale-21 (LMS21; novelty producing/seeking, engagement, flexibility), Perceived Stress Scale (PSS), FAD-Plus (free will, scientific determinism), PANAS-SF. Analyses included one-way ANOVAs and correlations between traits and fatigue measures. Data: https://doi.org/10.7910/DVN/CBOYWO.
• Study 5 (Arm-Hold with Mindfulness/Discontinuity Interventions): 55 Prolific participants (M_age=25) completed LMS14, reaction-time “odd shape” test (pre/post), then randomized to: (a) Discontinuous (told 5 min, then unexpectedly asked to repeat another 5 min; total 10), (b) Mindless/continuous 10 min, (c) Mindful/continuous 10 min with finger-focusing novelty subtask cycling fingers. FS/FP self-reported in minutes on a 1–10 min slider; willingness-to-repeat compensation query in session 2. Objective observer rated 30 s clips at ~2–2:30 and ~9–9:30 min (1–5 fatigue). Pre-registered on OSF: https://osf.io/j9xqd. Data: https://doi.org/10.7910/DVN/CBOYWO.

Across studies, perceived fatigue followed proportional milestones, typically FS around halfway and FP around three-quarters of task duration, largely independent of absolute duration or load, supporting a fatigue illusion.

• Study 1 (Travel): FS ~50% and FP ~74–82% across 3–5 h, 6–10 h, and ≥11 h trips; no significant differences among duration groups for FS (F(2,25)=0.11, p=0.90) or FP (F(2,25)=0.50, p=0.61); fatigue levels at FS/FP did not differ significantly.
• Study 2 (Counting + EEG): Overall FS=55.6% (SD=29.31), FP=70.9% (SD=27.39); FS earlier than FP (t(293)=−9.92, p<0.001, d=0.58). No between-group differences for FS (F(2,291)=0.60, p=0.55) or FP (F(2,291)=0.29, p=0.75). FP fatigue level increased with load (200<400<600; F(2,291)=3.26, p=0.04). Perceived “most mistakes” concentrated in 4th quintile; discontinuation desire more common in higher-load groups. EEG showed alpha amplitude peaks around reported fatigue periods (stages 3–5, peak at 7) with entropy changes indicating compensation and alertness resumption at task end, suggesting endurance and non-depletion at FP.
• Study 3 (Ballerina): Dancers’ FS=32.6% (SD=15.3), FP=70.7% (SD=19.9); FS earlier than FP (t(11)=−9.16, p<0.001, d=2.15). No significant gender differences; SH vs. LH did not differ on standardized FS/FP. Observer ICC: FS poor (0.29), FP good (0.66). PANAS-derived perseverance/aversion factors did not correlate with FS/FP.
• Study 4 (Hand-grip): No-goal group showed earlier milestones (FS=32%, FP=44%) than timed groups. 120 s: FS=62%, FP=83%; 180 s: FS=58%, FP=79%; 240 s: FS=40%, FP=62%. ANOVAs significant for FS (F(3,87)=8.8, p<0.001) and FP (F(3,87)=18.32, p<0.001); No-goal significantly earlier than others; 240 s earlier than 120/180. Levels of fatigue at FS/FP did not differ across groups. Stress correlated with higher FP fatigue (r=0.180, p=0.044) and shorter hold (r=−0.218, p=0.019). LMS21 total did not shift FS/FP timing, but higher mindfulness (novelty seeking/producing/engagement) correlated with lower fatigue levels at FS (r≈−0.20 to −0.30) and novelty producing with lower FP fatigue (r=−0.210, p=0.023).
• Study 5 (Interventions): Overall FS=45% (≈4.5 min), FP=64% (≈6.4 min); FS earlier than FP (t(54)=−6.15, p<0.001, d=2.29). No significant differences among the three conditions for FS (F(2,52)=1.775, p=0.180) or FP (F(2,52)=0.499, p=0.610). Mindful vs. discontinuous comparison indicated later FS/FP in mindful (t(34)=−1.88, p=0.035, d=−0.628); mindful FS (53%) significantly later than overall FS (z=2.69, p<0.01). Reaction times improved only in discontinuous condition (post < pre); ANOVA showed condition effects post (F(2,52)=4.11, p=0.022). Observer ratings showed greater fatigue in later vs. early clips (F(1,10)=14.54, p<0.01), no condition differences. Regression: Trait/state mindfulness did not predict FS; novelty producing predicted earlier FP (β=−0.481, p<0.001).

Findings consistently support that perceived fatigue is anchored to relative milestones within tasks rather than absolute energy depletion. Across cognitive and physical contexts, FS typically occurs around the midpoint and FP around three-quarters of the task, with abatement toward the end—consistent with teleoanticipation and the proposed fatigue illusion. Objective EEG and observer ratings corroborate that physiological/behavioral signs intensify around subjective fatigue reports, yet do not imply exhaustion at FP. Physical tasks sometimes shifted FS earlier (e.g., ballet developpé), suggesting task-specific difficulty and technique may modulate the placement of milestones without negating their proportional nature. Mindfulness-related constructs influenced the experience but not generally the timing of fatigue milestones. Higher Langerian mindfulness facets (novelty producing/seeking/engagement) were associated with reduced subjective intensity of fatigue (especially at FS), while stress related to greater fatigue and shorter persistence. Providing explicit goals/endpoints (timed conditions) deferred FS/FP relative to no-goal tasks, indicating that reference points shape teleoanticipation and energy allocation. Discontinuity (unexpected task extension) and mindful subtasks yielded nuanced effects: overall FS/FP proportions remained robust, but mindful instructions could defer FS relative to overall norms, and discontinuity appeared to restore post-task alertness (faster reaction time), possibly via reappraisal or novelty. Collectively, the results advance a monistic mind/body account: perceptions shape physiological engagement during challenging tasks, and altering frames (goals, novelty, discontinuity) can change fatigue experience and, in some cases, timing. This has implications for performance, endurance, and health, suggesting that managing the cognitive frame may enhance capacity without changing objective reserves.

Across five studies, the authors demonstrate a robust “fatigue illusion”: people typically perceive fatigue to begin around the midpoint and peak around three-quarters through a task, independent of task length, type, or difficulty, with abatement before completion. Objective indices (EEG, observer ratings) align with subjective milestones but do not indicate true depletion at FP, supporting a mind/body unity perspective. While trait and state mindfulness generally did not shift the timing of FS, mindfulness facets reduced the felt intensity of fatigue; explicit goals and discontinuity reframed energy allocation and could shift or manage milestones. The work contributes a practical metric—timing and duration of fatigue—for research and interventions, suggesting that reframing tasks via Langerian mindfulness (creating novelty, flexible categorization) can help postpone or mitigate fatigue. Future directions include: clarifying how discontinuity and self-chosen mindful strategies impact FS/FP; integrating physiological measures of deviation from the proto-Self with subjective milestones; testing across cultures and extreme task demands (e.g., very prolonged sleep deprivation) to delineate the boundaries of the illusion; and exploring personalized, intrinsically motivated mindfulness approaches to optimize fatigue management.

• Study 1 relied on retrospective self-reports of travel, vulnerable to recall bias and variability in mental tedium.
• Small samples in Study 3 (ballet) limit power; inter-rater reliability for FS was poor; some gender/time effects approached significance but were inconclusive.
• Physical tasks showed earlier FS, indicating task-specific difficulty may shift milestones; generalizability across all physical domains is uncertain.
• Interventions in Study 5 were pre-prescribed; participants did not select mindful strategies, potentially reducing intrinsic motivation and ecological validity; ancillary behaviors (e.g., checking phones) were not controlled.
• EEG used a single-channel consumer device (Neurosky); spatial resolution is limited; entropy analyses were coarse-grained across stages.
• The hand-grip study included only males; generalizability by gender may be limited.
• Objective observer ratings in Study 5 were based on brief clips and a single rater; condition-level differences were not detected.
• The precise effect of discontinuity (postponing vs. advancing fatigue) remains ambiguous and requires targeted designs to disambiguate.
• Samples were primarily students or specific professionals (dancers), which may limit broader population generalizability.