Prefrontal cortex oxygenation is preserved and does not contribute to impaired neuromuscular activation during passive hyperthermia
Bibliographic record
Abstract
We investigated the role of passive hyperthermia upon motor unit activation and prefrontal cortex oxygenation. Six healthy males were passively heated, using a liquid conditioning garment in a hot environment (35 degrees C, 50% relative humidity). Maximal force output and voluntary activation were examined during a 10 s maximal isometric knee extension. Of the initial 6 subjects, 1 experienced syncope at a rectal temperature (Tre) of 38.0 degrees C and was removed from the study. The remaining 5 subjects completed heating and testing to a Tre of 38.5 degrees C (n = 1), 39.0 degrees C (n = 3), or 39.5 degrees C (n = 1), and then were cooled back to baseline. Force production decreased from 553 +/- 133 to 430 +/- 176 N (p < 0.01) with passive heating, as did voluntary activation (from 90 +/- 5% to 84 +/- 7%). Percent heart rate reserve increased from 8 +/- 5% to 59 +/- 3% before returning to 4 +/- 8% (p < 0.001). Although mean arterial pressure remained unchanged, there were significant decreases in diastolic blood pressure with heating (80 +/- 3 to 63 +/- 8 mm Hg). Passive heating did not alter prefrontal cortex oxygenation, but cooling back to baseline core temperature attenuated cerebral oxygenated and total hemoglobin levels (p < 0.05). Passive heating to the point of voluntary exhaustion elevated cardiovascular and thermal strain and subjective perceptions of thermal discomfort. However, while this resulted in a marked decrement in maximal isometric force production and central voluntary activation, no concomitant changes in cerebral oxygenation were observed, suggesting that overall cerebrovascular regulation was maintained.
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 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) | 0.000 | 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) | 0.000 | 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".