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Record W4409009772 · doi:10.1073/pnas.2421281122

Validating new limits for human thermoregulation

2025· article· en· W4409009772 on OpenAlexafffund
Robert D. Meade, Fergus K. O’Connor, Brodie J. Richards, Emily J. Tetzlaff, Katie E. Wagar, Roberto C. Harris‐Mostert, Theodore Egube, James J. McCormick, Glen P. Kenny

Bibliographic record

VenueProceedings of the National Academy of Sciences · 2025
Typearticle
Languageen
FieldEnvironmental Science
TopicClimate Change and Health Impacts
Canadian institutionsOttawa HospitalUniversity of Ottawa
FundersNatural Sciences and Engineering Research Council of CanadaMitacs
KeywordsThermoregulationInflection pointRelative humidityHumidityCore (optical fiber)ThermodynamicsEnvironmental scienceAtmospheric sciencesMaterials sciencePhysicsMathematicsBiologyEcologyGeometryComposite material

Abstract

fetched live from OpenAlex

Recent projections suggest that large geographical areas will soon experience heat and humidity exceeding limits for human thermoregulation. The survivability limits modeled in that research were based on laboratory studies suggesting that humans cannot effectively thermoregulate in wet bulb temperatures (T wb ) above 26 to 31 °C, values considerably lower than the widely publicized theoretical threshold of 35 °C. The newly proposed empirical limits were derived from the T wb corresponding to the core temperature inflection point in participants exposed to stepped increases in air temperature or relative humidity in a climate-controlled chamber. Despite the increasing use of these thermal-step protocols, their validity has not been established. We used a humidity-step protocol to estimate the T wb threshold for core temperature inflection in 12 volunteers. To determine whether this threshold truly demarcates the T wb above which thermoregulation is impossible, each participant was subsequently exposed to T wb above (~33.7 °C, T above ) and below (~30.9 °C, T below ) their respective inflection point (~32.3 °C, T wb ) for up to 9 h (in random order). Core temperature rose continuously in T above . It was projected that core temperatures associated with heat stroke (40.2 °C) would occur within 10 h. While T below was also uncompensable, the core temperature rate of rise was considerably lower than in T above such that it would take >24 h to reach 40.2 °C. Our study supports thermal-step protocols as an effective technique for evaluating survivability limits for heat exposure and provides a direct assessment of the limits of human thermoregulation.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.034
metaresearch head score (Gemma)0.086
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.034
Threshold uncertainty score0.178

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0340.086
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.001
Bibliometrics0.0010.001
Science and technology studies0.0010.004
Scholarly communication0.0040.004
Open science0.0040.004
Research integrity0.0020.003
Insufficient payload (model declined to judge)0.0030.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.150
GPT teacher head0.399
Teacher spread0.249 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations15
Published2025
Admission routes2
Has abstractyes

Explore more

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