Post-Exertional Malaise: A Recovery-Phase Termination Failure

Introduction

Post-exertional malaise (PEM) is the defining feature of myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS), yet it is frequently misinterpreted as an exertion-time energy deficit, a damage-accumulation process, or a purely symptomatic reaction. This page defines PEM mechanistically as a recovery-phase termination failure: the system can meet the immediate demands of a stressor, but fails to complete coordinated shutdown afterward.

In the GLA v2.7 framework, exertion is treated as a coordination stress test, not a primary insult. The critical variables are termination quality and recovery convergence: stress increases attempt pressure A(t), while state-dependent timing noise lowers closure probability pᵢ(t) and increases effective resolution time τᵢ,eff. PEM emerges when recovery does not fully close and residual activity persists into the recovery window, producing delayed symptom amplification and prolonged tails under repeated identical loads.

This document provides a unified mechanistic chain that applies across trigger modalities. Physical activity, orthostatic stress, cognitive/emotional load, heat, and post-infectious stressors can all provoke PEM because they converge on the same failure mode: termination non-closure and recovery-phase coordination debt. Downstream expression may differ (vascular symptoms, cognitive fog, muscle weakness), but the governing failure is the same.

The sections that follow define the v2.7 updates, establish the functional roles of IAC → SRL → Axis-1 → RDM → Axis-2 → MLL, and then present the mechanistic chain in two sections: (I) how termination fails and Axis-1 load accumulates during recovery, and (II) how delayed collapse is expressed and becomes persistent through duration encoding and maintenance throttling.

What’s New in GLA v2.7 (Framework Update)

GLA v2.7 preserves the core claim established in earlier versions—that post-exertional malaise (PEM) is a recovery-phase failure rather than an exertion-phase energy deficit—but introduces a critical refinement in how persistence, progression, and delay are mechanistically framed.

1) Persistence is now formalized as duration memory arising from termination failure

In v2.6, persistence was emphasized through downstream recovery-phase amplifiers, particularly red-blood-cell–derived extracellular vesicles (RBC–EVs) and clearance-limited circulatory signals. In v2.7, persistence is re-anchored upstream and formalized as Recovery Duration Memory (RDM): the system-level encoding of unfinished recovery time produced by repeated Signal-Resolution Layer (SRL) non-closure.

This reframing clarifies that what accumulates across episodes is duration, not activation or damage. Identical loads can therefore produce different outcomes depending on recovery completion state, explaining delay, non-linearity, and history dependence without invoking escalating exertional intensity.

2) ER–mitochondrial interfaces are defined as the continuous Axis-1 locus

GLA v2.7 explicitly defines ER–mitochondrial (ER–MAM) interfaces as the continuous physical locus where recovery-phase work accumulates immediately following SRL non-closure. Rather than treating ER–MAM failure as a late downstream event, v2.7 positions these junctions as the execution surface from the earliest moments of incomplete termination onward.

This resolves ambiguity around timing: Axis-1 load begins silently during recovery, even when outward physiological measures normalize, because Ca²⁺ reuptake, redox reset, and membrane completion must converge at ER–MAMs to finish recovery.

3) Adipose tissue is repositioned as the dominant duration buffer

A major update in v2.7 is the repositioning of visceral adipose as the dominant duration buffer once termination is compromised. Adipose tissue is not treated as a disease initiator, nor as a trigger of SRL failure. Instead, its slow turnover makes it uniquely capable of stabilizing prolonged recovery modes through low-amplitude, long-duration endocrine, substrate, and immune signals after non-closure has already occurred.

This shift explains why recovery tails lengthen over time even under reduced activity and why rest alone often fails to restore baseline once duration memory is established.

4) RBC–EVs are tightened to a secondary, severity-modulating role

RBC-derived extracellular vesicles remain mechanistically relevant in v2.7 but are repositioned as secondary amplifiers and severity indicators, reflecting shear variability, near-wall signaling noise, and clearance dynamics during recovery. They are no longer treated as the primary driver of persistence duration. This distinction sharpens causal ordering and prevents downstream readouts from being misinterpreted as upstream memory mechanisms.

5) Termination bias replaces activation bias as the organizing failure variable

Finally, v2.7 clarifies that tissue memory can bias failure in two distinct ways—activation-biased (e.g., defensive overshoot in shedding-dominant phenotypes) and termination-biased (reduced bandwidth to exit stress in deficient-dominant phenotypes)—without altering the upstream ordering of SRL → Axis-1 → Axis-2 → MLL.

Framework Overview: Functional Roles of GLA Layers (v2.7)

This document uses a layered control architecture to distinguish initiation, termination, persistence, and maintenance in post-exertional malaise (PEM). Each layer has a distinct functional role and strict causal ordering. Downstream layers cannot initiate upstream failure, and persistence arises only after termination has failed.

Initiation-Adjacent Constraints (IAC)

Function: Sets baseline vulnerability and gain.

IAC describes pre-existing system properties—arising from Layer-0 influences such as genetic architecture and long-lived tissue state—that determine how easily termination precision is degraded under stress. These include membrane stability, autonomic gain, shear sensing, receptor anchoring, and baseline control-surface resilience. IAC shapes susceptibility to failure but cannot accumulate persistence or encode duration on its own.

Signal-Resolution Layer (SRL)

Function: Authorizes and completes exit from stress.

SRL governs stop-signal fidelity and coordinated shutdown across autonomic, vascular, immune, and cellular systems. When SRL closure succeeds, recovery converges cleanly. When SRL closure fails, the system exits stress incompletely, leaving residual activity after the stressor has ended. This is the first point at which history dependence becomes possible.

Axis-1 (Recovery-Phase Execution Load)

Function: Carries unfinished recovery work.

Axis-1 represents queued recovery tasks—Ca²⁺ reuptake, redox reset, and membrane completion—that accumulate immediately following SRL non-closure, primarily at ER–mitochondrial (ER–MAM) interfaces. Axis-1 load reflects unfinished work, not pathological stress or damage. It begins silently during recovery, even when outward physiological measures normalize.

Recovery Duration Memory (RDM)

Function: Encodes how long recovery remains unfinished.

RDM is the system-level memory of unresolved recovery time produced by repeated SRL non-closure and Axis-1 accumulation. It encodes duration, not activation magnitude or injury. RDM explains delay, non-linearity, and history dependence: identical loads can produce different outcomes depending on recovery completion state. Slow-turnover tissues bias the system toward prolonged recovery modes once RDM is established.

Axis-2 (Maintenance Allocation Control)

Function: Regulates investment in long-term repair and protection.

Under sustained Axis-1 demand, Axis-2 actively governs whether energetically costly maintenance programs are permitted to run. These include membrane lipid remodeling, glycome production, antioxidant capacity renewal, and proteostatic repair. Axis-2 does not fail passively; it enforces maintenance austerity when recovery demand exceeds available bandwidth, prioritizing short-term stability over long-term rebuild.

Maintenance Lock Layer (MLL)

Function: Enforces structural non-recoverability.

MLL represents the state in which rebuild capacity becomes structurally unreachable even at rest, due to chronic maintenance permission failure (NAD-effective → SIRT1-effective → c-Myc maintenance axis). Once engaged, reducing load can prevent new coordination debt but cannot restore baseline control without reopening maintenance permission. MLL reflects enforced maintenance policy, not cumulative damage.

SRL Termination Bias — Extended Synthesis with Adipose Duration Encoding (GLA v2.7)

The Signal-Resolution Layer (SRL) governs whether physiological stress responses terminate cleanly or exit incompletely into recovery. SRL failure is not defined by excessive activation, metabolic insufficiency, or inflammation; it is defined by a reduced probability of coordinated shutdown across autonomic, endocrine, immune, and cellular domains.

Termination bias arises when stop-signal machinery becomes state-dependent and unreliable. In this condition, initiation pathways remain intact, but closure probability is capped. Systems respond appropriately to stress yet fail to disengage fully, leaving residual activity that persists beyond the stressor.

A central example is glucocorticoid receptor (GR) termination failure, in which maximal shutdown capacity is reduced despite normal or elevated circulating hormone. This produces a characteristic pattern: preserved sensitivity, preserved activation, but impaired completion. Similar termination bias arises from access gating, receptor-state stabilization, kinase-enforced persistence, and transport or chromatin-level execution failure. Collectively, these mechanisms reduce closure probability (p ↓), increase slow-mode weighting (w ↑), and lengthen effective resolution time (τ_eff ↑) without increasing load magnitude.

Critically, SRL failure alone does not encode persistence. Persistence emerges only when incomplete termination is recorded into a slow, memory-bearing substrate. In GLA v2.7, visceral adipose tissue is identified as the dominant biological site of this duration encoding.

Adipose tissue functions as a recovery-phase integrator, not a stress initiator. Through tissue-local glucocorticoid regeneration (11β-HSD1), substrate routing, trophic neuropeptide signaling, and slow immune–metabolic programs, adipose converts transient termination failure into extended low-amplitude signaling that persists across rest. This does not sustain inflammation or drive acute symptoms; instead, it stabilizes slow recovery modes, increasing w and τ_eff across cycles and making subsequent closure progressively less likely.

In control terms, adipose acts downstream of SRL as a duration amplifier: it does not lower closure probability directly, but it prolongs the time window over which non-closure consequences remain active. This explains why PEM is delayed, why identical loads worsen outcomes over time, and why rest alone eventually fails to restore baseline.

One-line lock: SRL failure determines whether stress ends; adipose tissue determines whether incomplete endings are forgotten or remembered.

How to Read This Mechanistic Chain

The sections that follow describe a causal sequence, not a checklist of required abnormalities. Each step represents a functional transition that may be subclinical, reversible, or intermittently expressed. Early steps can occur without later ones, and later steps reflect stabilization of failure rather than escalation of injury.

The chain should be read as state-dependent and history-dependent, with progression determined by recovery completion rather than exertional intensity. Load reduction lowers attempt rate but does not erase accumulated recovery debt without restored termination.

Section I — How Mental Exertion Creates Recovery-Phase Termination Failure

1. Stress increases coordination demand, not energy demand

Mental exertion (cognitive load, emotional salience, vigilance, decision-making, orthostatic challenge) does not overwhelm metabolic capacity. Instead, it increases coordination demand across tightly coupled systems, including:

• autonomic onset/offset timing
• baroreflex gain and withdrawal precision
• endothelial shear decoding
• ER–mitochondrial (ER–MAM) Ca²⁺ release–reuptake coordination
• redox and thiol reset chemistry

No tissue is damaged. No ATP crisis occurs. The only variable that increases meaningfully is attempt rate, A(t), reflecting increased coordination pressure rather than increased energetic throughput.

Skeletal muscle is a dominant execution surface because it has the highest combined perfusion and Ca²⁺ coordination demand. Excitatory–inhibitory imbalance and β₂-adrenergic dysfunction lower tolerance for timing noise but do not constitute an energy deficit or disease initiator (Scheibenbogen & Wirth, 2025).

Mental exertion therefore acts as a stress test of recovery convergence rather than as a damaging event, explaining why similar cognitive loads may resolve normally in healthy systems but precipitate failure when recovery control is already fragile (Gianaros et al., 2012; Gordan et al., 2015).

Evidence base: Gianaros et al. (2012); Gordan et al. (2015); Scheibenbogen & Wirth (2025); Naviaux et al. (2016)

2. Nitric oxide transiently degrades termination precision

Acute stress elevates nitric-oxide–linked timing effects in autonomic and brainstem integration nuclei. Nitric oxide (NO) does not increase workload or energy use. Instead, it functions as a state-dependent timing noise injector that transiently degrades termination precision.

Specifically, NO:

• suppresses baroreflex gain
• degrades vagal stop-signal fidelity
• delays sympathetic withdrawal

These effects lower closure probability, p_i(t), across coupled control loops without increasing attempt rate or metabolic load (Daubert & Brooks, 2007; Gianaros et al., 2012).

In healthy systems, this timing noise resolves rapidly. In vulnerable systems, it does not. Parasympathetic suppression primarily degrades termination authorization rather than opposing sympathetic drive; recovery fails when coordinated stop-signals across vascular, renal, and immune loops remain unavailable despite appropriate activation.

Noradrenergic dysregulation further alters gain and withdrawal precision of autonomic and motor circuits, increasing susceptibility to termination noise without determining recovery duration (Gordan et al., 2015). Severe autonomic mis-timing alone, however, can remain confined to excitability without delayed PEM, demonstrating that timing noise is necessary but not sufficient (Vandenberk et al., 2023).

Evidence base: Daubert & Brooks (2007); Gianaros et al. (2012); Gordan et al. (2015); Vandenberk et al. (2023, negative control)

3. SRL non-closure leaves residual activation

Because termination precision is degraded, shutdown across systems becomes asynchronous. A small but critical residue of:

• Ca²⁺ micro-signaling
• redox activity
• autonomic activation

persists beyond the stressor. This defines Signal-Resolution Layer (SRL) non-closure. Nothing dramatic happens yet—but the system exits stress incompletely. This is the first point at which history dependence becomes possible.

Reduced handoff fidelity at ER→ERGIC→Golgi interfaces—regulated by Rab1—lowers the probability that recovery-phase export and progression complete cleanly, increasing the likelihood that unresolved states persist beyond the stressor. This reflects SRL non-closure driven by coordination failure rather than loss of throughput or energy capacity (Ito & Boutté, 2020; Wang et al., 2020).

Autonomic evidence indicates SRL non-closure reflects impaired enforcement and coordination of stop-signals (not signal absence), consistent with persistent vagal traffic that fails to converge on decisive termination (Kavelaars et al., 2000; de Matos et al., 2025).

Recovery-phase extracellular vesicle (EV) signatures of ER completion and quality-control programs peak early and remain abnormal at 24 hours, providing an independent readout that SRL closure fails to complete even after the initiating stressor has ended (Glass et al., 2025; Giloteaux et al., 2024).

SRL non-closure lands on ER–MAM coordination surfaces

SRL non-closure does not remain confined to abstract control loops. Coordinated termination of autonomic, endocrine, immune, and cellular stress programs requires convergence at shared physical resolution surfaces, most prominently endoplasmic reticulum–mitochondrial (ER–MAM) interfaces.

ER–MAM junctions are where recovery-phase termination must complete: Ca²⁺ must be resequestered, redox signals must resolve, lipid and membrane repair must finish, and trafficking programs must exit retry states. When SRL closure fails, these processes do not shut down synchronously. Instead, ER–MAM interfaces remain partially engaged, carrying forward low-amplitude Ca²⁺ transfer, redox activity, and membrane-completion work into the recovery window.

This is not ER stress, mitochondrial damage, or energy failure. It is incomplete execution of recovery. SRL non-closure therefore expresses immediately as persistent coordination demand at ER–MAM interfaces, establishing the earliest form of Axis-1 load before any overt symptoms appear.

Evidence base: Glass et al. (2025); Giloteaux et al. (2024); Kavelaars et al. (2000); de Matos et al. (2025); Ito & Boutté (2020); Wang et al. (2020)

4. ER–MAM immediately begins accumulating Axis-1 load

Even before overt failure, ER–mitochondrial interfaces (ER–MAMs) are already carrying load. Because Ca²⁺ and redox termination must converge at ER–MAM junctions:

• Ca²⁺ reuptake is slightly delayed
• mitochondrial Ca²⁺ exposure is prolonged
• redox reset lags

Axis-1 load therefore begins accumulating silently during recovery, without exertion and without damage.

Altered ER–mitochondrial lipid exchange involving PTDSS1/PISD, together with selective ether-phosphatidylcholine depletion, indicates persistent membrane-completion demand concentrated at ER–mitochondria interfaces. This supports ER–MAMs as a continuous locus of silent Axis-1 load accumulation, even at baseline (Missailidis et al., 2025).

When ER–Golgi coordination is inefficient, ER membranes and trafficking resources remain engaged longer in unresolved export and sorting attempts. This increases competition for ER recovery bandwidth at ER–MAM junctions, reinforcing Axis-1 load accumulation without invoking increased biosynthetic demand (Ito & Boutté, 2020).

Delayed parasympathetic recovery sustains endothelial and renal compensation signals, further increasing competition for ER–MAM recovery bandwidth even when bulk outputs normalize (Gordan et al., 2015).

ER–MAM load reflects queued recovery work rather than pathological stress signaling, consistent with intact initiation and absent inflammatory escalation.

Critical clarification:
ER–MAM is the continuous physical locus of Axis-1 load from SRL non-closure onward—not a late downstream event.

Axis-1 load remains transient as long as ER–MAM coordination completes before the next perturbation. When recovery does not fully close, unresolved ER–MAM work is carried forward in time rather than discharged. At this point, queued recovery work becomes encoded as duration rather than workload, marking the transition from Axis-1 execution load to Recovery Duration Memory (RDM).

Evidence base: Missailidis et al. (2025); Ito & Boutté (2020); Glass et al. (2025); Giloteaux et al. (2024); Gordan et al. (2015)

5. Persistent non-closure produces redox termination load

With repeated mental stress cycles, recovery-phase termination does not fully complete. As a result:

• ROS/RNS signaling does not fully reset
• antioxidant systems remain engaged
• NADPH demand persists
• thiol recycling load rises

This is not oxidative damage. It is failure of redox signal termination, in which redox chemistry becomes a persistence signal rather than a transient mediator of stress responses (Lamontagne et al., 2024).

At this stage, coordination debt is accumulating. Redox activity remains localized and functional, but its failure to resolve prolongs recovery-phase engagement across execution surfaces.

Increased membrane rigidity and selective ether–phosphatidylcholine depletion provide a physical basis for localized redox termination failure, allowing redox noise to persist without producing global oxidative stress markers or widespread cellular injury (Missailidis et al., 2025; Paul et al., 2021).

Recovery-phase extracellular vesicle (EV) proteomics demonstrate persistent dysregulation of ER redox-handling and completion machinery—including PDIA4, TXNDC5, ERP29, and HSPA5—that fails to normalize by 24 hours and correlates with PEM severity. This pattern supports a sustained “completion-in-progress” state rather than ER collapse or overt stress pathology (Glass et al., 2025; Giloteaux et al., 2024).

Evidence base: Lamontagne et al. (2024); Missailidis et al. (2025); Glass et al. (2025); Giloteaux et al. (2024); Paul et al. (2021)

6. Disulfide stress traps thiols (ratchet step)

Under sustained redox termination load, reversible thiol chemistry becomes progressively constrained:

• free cysteine increasingly forms protein disulfides
• reversible thiols become chemically unavailable
• NADPH is insufficient to reverse accumulated modifications
• redox-sensitive proteins remain functionally altered

This process constitutes thiol trapping, not protein loss, cell death, or irreversible oxidative injury. A previously reversible timing problem becomes progressively less reversible through localized, protein-specific disulfide locking rather than global redox imbalance (Lamontagne et al., 2024).

Importantly, this ratchet effect reflects loss of executability, not loss of biosynthetic capacity. Redox- and thiol-dependent control mechanisms remain present, but can no longer execute reliably under sustained recovery-phase load.

Enrichment of disulfide-handling and ER redox-completion proteins in recovery-phase EVs supports a completion-debt interpretation: systems remain engaged in thiol/disulfide correction and redox-coupled finishing work across cycles rather than resolving and exiting recovery cleanly (Glass et al., 2025; Giloteaux et al., 2024).

Throughout this chain, accumulation reflects time spent unresolved, not increasing exertional load or activation magnitude.

Evidence base: Lamontagne et al. (2024); Glass et al. (2025); Giloteaux et al. (2024); Alzubi et al. (2024, analogue)

End of Section I. Steps 1–6 define how termination failure arises and how unresolved recovery work accumulates silently during recovery, establishing the preconditions for delayed PEM expression.

Section II — How Termination Failure Becomes Muscle PEM

(Axis-1 execution → delayed recovery collapse → Axis-2 → Maintenance Lock Layer)

7. Thiol-based timing stabilization collapses (generalized, not H₂S-specific)

Disulfide stress disables thiol-dependent timing stabilizers across systems. Hydrogen sulfide (H₂S) is used here as a canonical example, not as a singular dependency.

Effective thiol-based control requires:

• free cysteine availability
• intact redox cycling
• membrane microdomain integrity
• coordinated mitochondrial participation

Loss of ether–phosphatidylcholine reduces local redox buffering and membrane microdomain stability, increasing the probability that thiol-dependent timing control becomes functionally unexecutable under repeated recovery-phase load, even when relevant enzymes remain present (Missailidis et al., 2025; Lamontagne et al., 2024).

With thiol trapping:

• CBS / CSE / MPST enzymes may still exist
• but sulfhydration-based control cannot execute

This represents loss of thiol-based executability, not “H₂S deficiency.” The failure reflects timing-dependent control loss, not loss of metabolic capacity or biosynthetic machinery (Lamontagne et al., 2024).

In skeletal muscle, redox- and Ca²⁺-sensitive ion-channel instability amplifies execution-surface fragility once thiol-dependent termination fails, worsening post-exertional suppression without initiating the failure itself (Scheibenbogen & Wirth, 2025).

Evidence base: Lamontagne et al. (2024); Missailidis et al. (2025); Scheibenbogen & Wirth (2025)

8. Skeletal-muscle execution surfaces become timing-fragile

Skeletal muscle is the dominant PEM execution surface because it has the highest combined Ca²⁺ and perfusion coordination demand.

Loss of thiol-based stabilization destabilizes:

• K_ATP channels
  reduced hyperpolarization protection; weaker defense against Ca²⁺ overload
• RyR1
  redox-sensitive gating becomes unstable; Ca²⁺ release duration increases; re-trigger probability rises
• SERCA
  reuptake timing becomes unreliable; Ca²⁺ clearance slows; termination variance increases

This is not ATP failure. Output is suppressed because timing is unsafe, not because energy is unavailable.

Preserved oxygen delivery with impaired utilization and depolarization-prone muscle membranes confirms skeletal muscle as the primary site where unresolved recovery is expressed, not where persistence is determined (Scheibenbogen & Wirth, 2025).

Evidence base: Scheibenbogen & Wirth (2025)

9. Parallel fragility in autonomic and brainstem circuits

The same thiol-dependent timing fragility occurs in:

• brainstem autonomic nuclei
• vagal and sympathetic termination circuits
• synaptic and ion-channel closure mechanisms

This is why purely cognitive or emotional stress can initiate the same Axis-1 load that later expresses as muscle PEM.

The critical bottleneck is failure to issue reliable termination-phase stop / reset / re-synchronize signals after stress. Autonomic activity may be elevated or uncomfortable without pathology; PEM becomes possible only when parasympathetic re-engagement, baroreflex offset, or endocrine disengagement fails to complete during recovery, allowing autonomic timing noise to persist beyond the initiating load (Gordan et al., 2015).

Negative control: Severe autonomic mis-timing can remain confined to excitability without delayed PEM (Vandenberk et al., 2023)

10. ER–MAM Ca²⁺ termination now fails overtly

Once execution surfaces are destabilized, ER–mitochondrial interfaces (ER–MAMs) become the dominant failure point:

• Ca²⁺ handoff becomes noisy
• mitochondrial Ca²⁺ exposure increases
• redox stress persists
• termination does not complete

Ca²⁺ persistence now functions as a history-dependent memory signal, biasing future cycles toward slower closure.

Formally:

• effective duration τ_i,eff increases
• slow-mode occupancy w_i increases

Persistent coordination failure at ER→ERGIC→Golgi handoff gates increases serial retry through stable intermediate compartments, biasing recovery trajectories toward long-residence states without altering intrinsic Ca²⁺ kinetics (Ito & Boutté, 2020).

ER–MAM Ca²⁺ termination requires upstream autonomic timing authorization. When parasympathetic recovery is delayed, OFF-states flicker instead of locking, reinforcing slow-mode dominance even when exertional load has ended (Gordan et al., 2015).

Importantly, preserved Ca²⁺ release or compensatory routing does not restore termination fidelity; recovery fails when refill and shutdown kinetics are degraded despite intact activation (Glass et al., 2025; Missailidis et al., 2025).

Evidence base: Glass et al. (2025); Missailidis et al. (2025); Ito & Boutté (2020); Gordan et al. (2015)

11. Recovery becomes the failure point (PEM)

The system tolerates the initiating load in the moment but fails afterward:

• delayed symptom amplification
• muscle weakness, heaviness, and pain
• dysautonomia and cognitive fog
• prolonged recovery tails

This is post-exertional malaise.

PEM is a recovery-phase failure, not an exertion-phase failure. The characteristic “false OK” window exists because instability is encoded during activation but expressed during recovery, when termination and repair processes fail to complete.

Delayed worsening of muscle weakness and intolerance reflects recovery-phase amplification of latent execution instability: vulnerability is unmasked by exertion but expressed only when recovery does not fully close (Glass et al., 2025; Giloteaux et al., 2024; Scheibenbogen & Wirth, 2025).

Evidence base: Glass et al. (2025); Giloteaux et al. (2024); Scheibenbogen & Wirth (2025)

12. Repetition encodes duration → Axis-2 persistence → Maintenance Lock

Repeated SRL non-closure produces:

• SRL tail persistence driven by repeated coordination retry at ER–Golgi and ER–MAM interfaces
• overlapping recovery tails that increase Axis-1 load without increasing exertional intensity

Visceral adipose acts as a dominant duration buffer, integrating prior stress exposure into low-amplitude, long-duration endocrine, substrate, and immune signals that stabilize slow recovery modes only after termination is compromised, without initiating disease or restoring closure.

Stabilized duration memory increases baseline recovery cost even in the absence of new exertion. This persistent, low-amplitude recovery demand is sensed by cellular allocation systems as an ongoing maintenance burden, forcing a shift from recovery execution to maintenance prioritization (Axis-2). This transition marks entry into Axis-2, where long-term repair and rebuild programs are actively throttled rather than passively failing (Zhang et al., 2021).

Under sustained demand, Axis-2 does not fail passively. Instead, it is actively throttled through metabolite- and energy-sensing permission gates that reduce investment in costly rebuild and protection programs.

Concretely, chronic recovery non-closure drives:

• decline in effective cyst(e)ine availability and reversal capacity
• reduced energy charge and nucleotide pools, limiting repair bandwidth
• translation gating of maintenance-critical proteins (e.g., GPX4 via Rag–mTORC1–4EBP)
• targeted proteolytic dismantling of sulfur-consuming maintenance pathways (e.g., LRRC58–CUL2–mediated CDO1 degradation)

These changes occur even when transcription remains intact and no structural damage is present (Zhang et al., 2021; Alzubi et al., 2024).

Reduced maintenance output destabilizes membrane and control-surface integrity (including SMPDL3B anchoring), lowering termination tolerance and feeding back to increase Axis-1 load per unit stress. This closes a self-reinforcing control loop:

incomplete termination → rising maintenance demand → maintenance throttling → poorer future termination

Axis-2 persistence therefore reflects active maintenance austerity, not damage accumulation. Once rebuild capacity becomes structurally unreachable even at rest, the system enters the Maintenance Lock Layer (MLL) (Missailidis et al., 2025).

Load reduction can prevent new coordination debt but cannot reopen closed maintenance permission gates. Improving coordination may shorten recovery tails early, but cannot restore baseline control once Axis-2 throttling and MLL engagement are established.

At this stage, persistence reflects stabilization of a slow attractor governed by duration memory (e.g., adipose persistence) and enforced maintenance policy, rather than irreversible injury or ongoing activation.

Evidence base: Zhang et al. (2021); Missailidis et al. (2025); Alzubi et al. (2024, analogue)

End of Section II.

Section II summary.
Section II shows how recovery-phase termination failure is expressed as post-exertional malaise. Persistent SRL non-closure produces redox and thiol termination load that destabilizes timing-dependent control across execution surfaces, with skeletal muscle and autonomic circuits acting as dominant expression sites rather than persistence generators. As termination reliability degrades, ER–MAM Ca²⁺ handling fails overtly, converting incomplete recovery into delayed symptom amplification—the defining feature of PEM. Repetition encodes duration rather than damage, engaging adipose-mediated duration buffering and forcing a shift from recovery execution to active maintenance throttling (Axis-2). When sustained recovery demand exceeds rebuild capacity, maintenance permission becomes structurally unavailable, culminating in the Maintenance Lock Layer (MLL). Thus, PEM severity and progression reflect failure of recovery completion and duration control, not exertion-time energy collapse or cumulative tissue injury.

Interpretive Framework Documents (GLA v2.1 → v2.5)

The documents listed below define the conceptual and methodological framework used to interpret genetic signals and physiological mechanisms in this paper. Collectively, they establish layer boundaries, phenotype discipline, and phase dependence within the Gut–Liver–Autonomic (GLA) system architecture.

These materials are provided for transparency and interpretive context only. They are not cited as evidentiary sources and should be read as evolving systems-biology models used to organize and constrain interpretation, rather than as claims of mechanism or causation.

GLA v2.7 — Canonical framework

Current authoritative mechanistic models defining PEM as a recovery-phase failure.

Framework documents

Core architecture and definitions that anchor the GLA model.

Papers

Longer, paper-format documents (reader narrative + figures).

Modules (v2.1 → v2.6)

Modular “building blocks” used across the site. Organized by version and topic.

SMPDL3B phenotype frameworks

Phenotype-specific models (shedding vs deficient) and the mechanistic chain framework.

System modulators & control-state modifiers

Documents that shape interpretation of the core framework and control-state behavior.