Electric Fan Use On Autophagy And Apoptosis In Older Adults During An Extreme Heat Simulation
Bibliographic record
Abstract
We recently showed that older adults sustain greater increases in core temperature during daylong exposure to extreme heat (40 °C) compared to their younger counterparts. This was associated with signs of autophagic impairments paralleled with greater apoptotic signaling. Recent guidance has advocated the use of electric fans as a simple and sustainable cooling strategy to safeguard older adults during extreme heat. While we showed that fans have small negligible impacts on core temperature during daylong (8-h) heat exposure (36 °C), their cellular impact remains unknown. PURPOSE: To assess changes in cellular stress responses (autophagy and apoptosis) in older adults exposed to a daylong heatwave simulation with and without the use of a pedestal-mounted electric fan. METHODS: 18 participants (8 females, median age 72 [IQR, 67-76] years) were exposed to 3 heatwave simulations (8-h, 36 °C, 45% RH) with a fan generating air speeds of either 0 (no fan, control), 2, or 4 m/s directed at the front of the body. Participants were seated throughout exposure except for 4 x 10-min periods of simulated activities of daily living (stepping [~2.25 METs]). Core temperature (rectal, Trec) was measured continuously, while proteins associated with autophagy (LC3-II) and apoptosis (caspase-3) were measured before and after each exposure in peripheral blood mononuclear cells via Western blot. Proteins are expressed as relative quantity (RQ [SD]) from baseline and were assessed via one-way ANOVA with Bonferroni correction (α = 0.05). RESULTS: Elevations in Trec were not different between conditions (~1.3 °C, all p ≥ 0.50). Changes in LC3-II were not different with fan use at 2 (1.79 RQ [0.80]) or 4 m/s (1.54 RQ [0.70]) compared to control (1.56 RQ [0.52]; all, p ≥ 0.095). While caspase-3 did not differ between control (1.20 RQ [0.35]) and with a fan at 2 m/s (1.37 RQ [0.45], p > 0.999), fan use at 4 m/s elicited a significant increase in caspase-3 (1.86 RQ [1.15]) when compared to control (p = 0.030). CONCLUSIONS: While fan use did not elicit changes in Trec or autophagy compared to control, fan use at 4 m/s elicited significant elevations in apoptotic signaling. Therefore, fan use at high settings during heatwaves may incur greater cellular stress in older adults. Supported by: Canadian Institutes of Health Research and Health Canada
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".