Whole‐body heat exchange in black‐African and Caucasian men during exercise eliciting matched heat‐loss requirements in dry heat
Bibliographic record
Abstract
New Findings What is the central question of this study? Black‐African descendants are thought, by some, to possess genotypic adaptations conducive to survival in hot climates. We therefore assessed whether Canadian residents of black‐African descent display enhanced whole‐body total heat loss (evaporative plus dry heat exchange) in comparison to Caucasian Canadians during exercise eliciting matched heat‐loss requirements in dry heat. What is the main finding and its importance? Neither whole‐body total heat loss nor body heat storage differed significantly between groups, irrespective of the exercise intensity. Our findings indicate that genotypic adaptations associated with ethnicity do not appreciably modify whole‐body heat exchange during exercise–heat stress. Abstract Ethnicity has long been thought to modulate thermoregulatory function; however, an evaluation of whole‐body heat exchange in men of black‐African descent and Caucasian men (white‐European descendants), born and raised in the same climate, during exercise eliciting matched heat‐loss requirements remained unavailable. We therefore used direct calorimetry to assess whole‐body total heat loss (evaporative plus dry heat exchange) in young (18–30 years of age), second‐generation (or higher) black‐African ( n = 11) and Caucasian ( n = 11) men. Participants performed three 30 min bouts of semi‐recumbent cycling at fixed metabolic heat productions (and therefore matched heat‐loss requirements between groups) of 200 (light), 250 (moderate) and 300 W m −2 (vigorous), each followed by 15 min recovery, in dry heat (40°C, ∼13% relative humidity). Across all exercise bouts, dry ( P = 0.435) and evaporative ( P = 0.600) heat exchange did not differ significantly between groups. As such, total heat loss during light, moderate and vigorous exercise was similar between groups ( P = 0.777), averaging [mean (SD)] 177 (10), 217 (13) and 244 (20) W m −2 in black‐African men and 172 (13), 212 (17) and 244 (17) W m −2 in Caucasian men. Accordingly, body heat storage across all exercise bouts (summation of metabolic heat production and total heat loss) was also similar between the black‐African [568 (142) kJ] and Caucasian groups [623 (124) kJ; P = 0.356]. We demonstrated that, when assessed in young, second‐generation (or higher) black‐African and Caucasian men during exercise eliciting matched heat‐loss requirements in dry heat, ethnicity did not significantly modulate whole‐body dry and evaporative heat exchange or the resulting changes in total heat loss and body heat storage.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
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".