{"publication_id":"7fbd93f4-7470-4fcd-8d68-576c76768953","screening":{"identified":33,"screened":33,"excluded":0,"included":33,"included_or_retained":33,"flow":["identified","screened","excluded_with_reasons","included"],"wording":"33 candidate receipts retained after source retrieval, deduplication, and topic filtering. This is an evidence-map screening trace, not a PRISMA full-text exclusion audit.","exclusion_reasons":["No PRISMA full-text exclusion-stage filter was applied."]},"limitations":["This is an agent-assisted evidence map, not a PRISMA-complete systematic review or clinical guideline.","It is not PROSPERO-registered and should not be read as medical advice.","Public sidecars expose citation traces and extraction status; empty fields mean not extracted, not assumed absent."],"contradictions":["The conclusion is that Aerobic exercise should be treated as a bounded geroscience hypothesis: the retained clinical and adjacent evidence profile defines the scope for targeted testing, while mixed and null findings limit any unqualified anti-aging claim.","The geroscience hypothesis offers a useful lens on why Aerobic exercise has become a recurring reference point in this debate. The hypothesis holds that interventions targeting the upstream biology of aging, rather than any single downstream disease, may yield larger and more durable effects on multimorbidity than disease-by-disease treatment strategies, and it has been operationalized most visibly in trials of candidate geroprotectors such as metformin, rapalogs, and senolytics. Within that framework, Aerobic exercise is interesting precisely because it does not fit cleanly into the repurposed-molecule or novel-development categories: it is a non-pharmacologic, behaviorally mediated stimulus with systemic effects on mitochondrial biogenesis, insulin signaling, low-grade inflammation, and vascular endothelial function, all pathways that drug candidates in the geroscience pipeline are also trying to engage. The intervention logic, in other words, converges: the question of whether Aerobic exercise modifies aging biology shares endpoints, surrogate markers, and mechanistic language with the question of whether metformin or any rapalog does so, and the field has been increasingly willing to hold Aerobic exercise to the same evidentiary standards. But there is an important asymmetry, namely that Aerobic exercise has no patent, no phase I/II/III roadmap, and no commercial sponsor with an interest in funding the long, hard-outcome trials that the geroscience community has so far largely failed to deliver for any candidate. The result is an evidence base that is dense with short-term surrogate-endpoint trials, sparse on hard clinical outcomes, and organized, when it is organized at all, around the conventions of sports medicine rather than those of aging research.","Several unresolved questions prevent any simple endorsement of Aerobic exercise as a geroscience intervention, and the sources themselves make those questions visible. The second concerns tradeoffs: a 12-week post-exercise hot-water immersion adjunct produced additional haemodynamic and vascular benefits in physically inactive middle-aged adults (mean age 58 ± 5 years, BMI 28 ± 3 kg/m²) but did not further improve cardiorespiratory fitness, glucose, lipids, or inflammation (Steward 2025), suggesting that added components may shift benefit distribution rather than amplify it. The third concerns population specificity, as outcomes in type 2 diabetes (OConnor 2025), obesity (Elsayed 2023, Jayedi 2024), COPD (Latimer 2022), and early Alzheimer's (Morris 2017) appear to vary with baseline comorbidity in ways that aggregated meta-analyses obscure. The fifth concerns dose-response itself, with the American College of Sports Medicine framework cited by Jayedi 2024 implying nonlinear effects of Aerobic exercise on weight loss that the available trials are not powered to resolve.","The contribution of this synthesis is to take the apparently simple question, does Aerobic exercise modify aging-relevant outcomes, and to decompose it into the smaller, more answerable questions that the sources can actually bear. The synthesis proceeds by weighting evidence at the level of outcome class rather than study, by separating clinical-outcome reports from mechanistic-surrogate reports, and by treating population specificity as a first-class variable rather than a nuisance term. It also explicitly refuses to assert that Aerobic exercise extends lifespan, prevents cognitive decline, or reverses multimorbidity on the basis of the present sources, framing the field's central question as the question of whether, for whom, and at what dose Aerobic exercise produces clinically meaningful gains on hard endpoints rather than surrogate ones, the kind of question for which the available evidence remains, at best, suggestive. The synthesis that follows is therefore structured as a weighted, tension-aware reading of the sources, not as a vote count, and its central claim is that the Aerobic exercise anti-aging case is mechanistically plausible and directionally favorable in some outcome classes, but is incomplete as currently constituted, and that the missing pieces are empirical rather than rhetorical.","At the preclinical and disease-model level, aerobic exercise is associated with a coherent set of physiological adaptations that map onto geroscience-relevant pathways, although the source-level evidence for any single mechanism is uneven. Mitochondrial remodeling has been documented in human skeletal muscle, where short-term cycling protocols produced reproducible transcript and protein-level adaptations in oxidative-phosphorylation machinery (Egan 2013), and similar mitochondrial responses have been observed in patient populations such as those with chronic obstructive pulmonary disease, where the maximal aerobic power per mitochondrion can be partially restored by training (Latimer 2022). Vascular mechanisms have been investigated using animal models of vascular aging, in which moderate-intensity aerobic exercise modulated nitric-oxide-dependent vasorelaxation and adropin signalling (Fujie 2021), and an exploratory histological study compared aerobic exercise against an alternative vascular-aging intervention in rats (Damay 2023). Translational relevance to humans remains uncertain. Cardiometabolic mechanisms have been examined in obese older adults, where combined exercise and phototherapy shifted hemostasis markers resistant to hypercoagulability (Elsayed 2023). However, not all mechanistic effects observed in disease models translate cleanly: in middle-aged inactive adults, adding post-exercise hot-water immersion enhanced some hemodynamic and vascular responses without producing additional improvements in cardiorespiratory fitness, glucose, lipids, or systemic inflammation (Steward 2025), illustrating that physiological signals sensitive to one manipulation may remain unchanged for adjacent endpoints. The cumulative picture from the preclinical and disease-model literature is therefore that aerobic exercise engages several plausibly geroprotective axes, but that effect direction and magnitude are endpoint-specific, an observation that carries forward into the human evidence base.","Several methodological questions recur across the aerobic exercise literature and constrain the strength with which clinical recommendations can currently be made. First, the endpoints most often reported are surrogate or intermediate outcomes — flow-mediated dilation, V̇O2peak, body-fat percentage, telomere length, cognitive composite scores — rather than hard clinical events, and the methodological caution that surrogate associations do not guarantee hard-outcome validity (Ioannidis 2005) applies directly to this evidence base. Second, intervention duration varies dramatically, from eight-week protocols (Hinchman 2022; Tanaka 2012) to twelve-month follow-ups (Voss 2010), and the trial-level signal sometimes emerges only at the longer timepoints, complicating dose-response inference. Third, comparator arms differ widely, ranging from non-exercise or stretching controls to active comparators such as phototherapy (Elsayed 2023), pioglitazone (OConnor 2025), or electronic cigarette exposure in animal work (Damay 2023), which limits cross-study comparability. Fourth, the literature includes both mechanistic and clinical outcomes within the same outcome classes, producing the tension patterns observed in the synthesis — for example, positive muscle-function signals in trials of glucose-intolerant or multimorbid adults (Baker 2010; Lo 2021) coexist with null or mixed signals in broader reviews of combination training (Bai 2022) and in longer-duration cognitive trials (Voss 2010; Hinchman 2022). Finally, concurrent interventions such as individualized programming, behavioral engagement, or adjunctive brain stimulation are common, raising the question of whether reported effects should be attributed to aerobic exercise per se or to the package in which it is delivered (Hinchman 2022; Thomas 2021; Lo 2021). Until these methodological questions are addressed through more standardized endpoints, longer follow-up, and more consistent comparator design, the aerobic exercise case as a geroprotector will continue to be characterized by mechanistic promise coexisting with mixed human-RCT evidence and unsettled boundary conditions.","Mechanistically, the three clinical or quasi-clinical sources speak to overlapping but non-identical cardiometabolic pathways. Steward 2025 isolates vascular and haemodynamic reactivity as the substrate responsive to thermal augmentation, leaving the canonical cardiometabolic risk markers (glucose, lipids, inflammation, fitness) unchanged beyond exercise itself. Elsayed 2023 implicates the coagulation-fibrinolysis axis, with laser phototherapy modulating hypercoagulability markers in obese seniors. Huang 2025 mechanistically grounds the body-fat signal in modality-specific energy expenditure and substrate utilization, where aerobic training exceeds resistance and combined regimens in sedentary adults. Preclinical and mechanistic data therefore support multiple distinct biological handles, while the human clinical RCT-level evidence for any single handle remains narrow.","Eighteen of the curated sources populate the contextual/mixed outcome class, and together they paint a heterogeneous picture that resists a single net-direction summary. These three sources anchor the contextual/mixed class with human-RCT or systematic-review evidence and supply the high-density numeric spine of this subsection (see the evidence synthesis for the full per-study p-value inventory).","The vascular-endothelial and arterial-stiffness sub-thread is dominated by null or directionally mixed findings despite robust continuous-aerobic RCT inputs. When read alongside Bull 2020, which articulates WHO 2000 physical-activity guidance rather than a primary endpoint, the vascular thread shows that statistical superiority versus sedentary comparators does not automatically translate into a positive verdict against active comparators — a recurrent pattern across the contextual/mixed class (Bull 2020; Tao 2023; You 2022).","Salisbury 2023 is the only corpus study mapped to the dosing/pharmacokinetics outcome class for aerobic exercise, and it is positioned as an indirect observational cohort in adults rather than a clinical RCT [Salisbury 2023]. The study correlated changes in cardiorespiratory fitness (CRF) with resting plasma neurotrophic factors in the setting of Alzheimer's dementia, treating the exercise dose–response relationship as a biomarker-mapping exercise rather than a pharmacokinetic clearance study [Salisbury 2023]. The endpoint of interest is therefore the correspondence between training-dose surrogates and downstream neurotrophic signaling, not drug-style absorption or distribution [Salisbury 2023]. The synthesis classifies this evidence as indirect because the dosing construct is operationalized through change-in-CRF rather than a quantified exercise prescription [Salisbury 2023].","Mechanistically, the mechanistic substrate underlying this null finding would normally invoke exercise-induced neurotrophin release, yet Salisbury 2023 found no detectable correspondence between CRF change and plasma neurotrophic factors, suggesting either that resting peripheral neurotrophins are insensitive to aerobic dose in Alzheimer's dementia or that the dosing construct itself was too loosely operationalized to detect an effect [Salisbury 2023]. Because the source carries directness = indirect and the design is observational, the study is better framed as hypothesis-generating for a future clinical RCT than as confirmatory mechanistic human data [Salisbury 2023].","Within the corpus there is no second dosing/pharmacokinetics study to triangulate Salisbury 2023, so no within-corpus tension can be named in this outcome class, and the brief's broader cross-class signal of null findings dominating contextual-other and cardiometabolic endpoints is consistent with — but not directly tested against — this single indirect cohort [Salisbury 2023]. Together these clinical RCT and cohort designs establish the trial summary for the muscle-function class: aerobic interventions of 8 weeks to several months, adult and older-adult populations, and physical-fitness or cardiorespiratory endpoints.","Egan 2013 is the single curated human-physiology study contributing to the skeletal, fracture, and bone outcome class, and it is positioned as indirect rather than direct evidence because its primary endpoint is molecular kinetics in skeletal muscle rather than a clinical fracture or bone-density outcome. The study is observational in design with a short, fixed exposure window and a very small cohort, which limits inferential strength for skeletal endpoints. No fracture incidence, bone mineral density, or surrogate imaging endpoint is reported; the only directness-relevant signal is that adaptation was measured in skeletal muscle tissue, not in bone. Readers should therefore treat any inference about bone outcomes from this source as exploratory rather than confirmatory.","Because these statistics index molecular adaptation in muscle, the relevant numerator is the number of gene/protein endpoints reaching P < 0.05 within the curated set, not a clinical fracture or bone-density effect size; the source does not provide a hazard ratio, odds ratio, or relative risk for any bone endpoint. No 95% confidence intervals are reported in the curated excerpt, and the source does not state a primary analytic endpoint. Effect direction is recorded as null for the skeletal fracture bone class because the molecular findings, while positive in muscle, do not translate within the source to a directional bone outcome.","Mechanistically, the Egan 2013 substrate is a short-term aerobic-exercise challenge in healthy sedentary adults, with molecular readouts in skeletal muscle; it is therefore best characterized as a mechanistic human study rather than a clinical RCT, and its applicability to skeletal fracture bone endpoints requires an inferential bridge from muscle adaptation to bone remodeling. That bridge is not made within the curated source, and the source itself does not assert any bone-relevant mechanism. In a broader anti-aging framework, an aerobic stimulus that drives repeatable transcript and protein responses in muscle (P < 0.05 across multiple gene/protein endpoints) is biologically plausible as a modifier of mechanotransductive loading on bone, but plausibility is not evidence and no bone endpoint is measured. The within-corpus record for this outcome class is therefore mechanistic-muscle data tagged to a skeletal outcome label, with directness acknowledged as indirect.","Within-corpus tension for the skeletal fracture bone class is minimal because Egan 2013 is the sole curated source in this outcome class and there are no non-orthogonal same-outcome pairs in the cross-study disagreement map to contrast against it. Readers comparing this outcome class against the broader synthesis should note that any apparent contradiction is a labeling artifact rather than a disagreement between studies. Consequently, the honest summary for this subsection is that the curated evidence base for skeletal, fracture, and bone outcomes in the Aerobic exercise literature is sparse, indirect, and not yet anchored by a clinical bone endpoint.","Quantitative findings cluster on the positive side of the effect-direction ledger for several entries but include a substantial block of null or unclear verdicts. Baker 2010 reported that six months of aerobic exercise improved executive function (MANCOVA, P = 0.04), cardiorespiratory fitness (MANOVA, P = 0.03), and insulin sensitivity (P = 0.05) in older adults with glucose intolerance. By contrast, Bai 2022 was tagged null at the review level, and Weber 2024 carried a mixed effect direction with P < 0.01, P = 0.016, P < 0.05, P < 0.001, P = 0.003, and P = 0.048 distributed across female-cognition sub-domains. The per-study p-value matrix is consolidated in the evidence synthesis (Per-Study Endpoint Evidence), which the prose here references rather than restates."]}