Does menthol independently modify thermoregulatory control during passive heat stress in humans?
Bibliographic record
Abstract
Introduction: Physical cooling within the gastrointestinal (GI) tract attenuates sudomotor activity likely by activation of the cold-sensitive transient receptor potential melastatin 8 (TRPM8). In the absence of physical cooling, it remains unknown whether stimulation of TRPM8 receptors within the GI tract during heat stress alters sudomotor control. Objective and Hypothesis: The purpose of this study is to assess whether a TRPM8 agonist (e.g., menthol) independently modulates the sudomotor response during heat stress. Relative to 37°C water, It was hypothesized that menthol would i) delay the sweating onset, and ii) attenuate the sweating response during heat stress. Methods: To date, a total of 9 participants (5 females; 22±5 y; 72.7±10.5 kg; 1.8±0.1 m) have completed three passive heating protocols on separate days. The participant’s rectal temperature was increased by 1.0°C above baseline using a water perfused suit circulating 49°C water. Participants consumed 3.2 ml per kg of body mass of either: i) 37°C water (37C), ii) 1.5°C water (1.5C), or iii) 37°C menthol solution (0.05%, 37M), 5 minutes before passive heating, and following a 0.5°C and 1.0°C increase in rectal temperature. Mean skin temperature (4 sites) and local sweat rate of the forearm and forehead were recorded during the baseline period and passive heating protocol. Mean body temperature was calculated as the weighted average between skin (20%) and rectal (80%) temperature, and whole-body sweat rate expressed as the net difference in body mass relative to heating time (in g/h). Results: Mean body temperature at baseline was not different between the three conditions (37C: 36.21±0.41˚C, 1.5C: 36.24±0.38˚C, and 37M: 36.30±0.43˚C, P=0.32). Forearm sweating onset was attenuated with 37M (36.97±0.42˚C, P=0.04), and trending to be attenuated with 1.5C (36.96±0.26˚C, P=0.07) relative to 37C (36.69±0.40˚C). Similarly, forehead sweating onset was attenuated with 37M (36.95±0.44˚C, P=0.02), and trending to be attenuated with 1.5C (36.84±0.35˚C, P=0.09), relative to 37C (36.70±0.43˚C). Thermosensitivity was not different between all three fluid conditions for the arm (37C: 1.4±0.7 mg/cm 2 /min/˚C; 1.5C: 1.7±1.0 mg/cm 2 /min/˚C; 37M: 1.5±1.0 mg/cm 2 /min/˚C, P=0.59) and head (37C: 1.7±0.9 mg/cm 2 /min/˚C; 1.5C: 1.6±1.2 mg/cm 2 /min/˚C; 37M: 1.7±1.1 mg/cm 2 /min/˚C, P=0.88). Lastly, whole-body sweat rate was not significantly different between all three conditions (37C: 631±288 g/h; 1.5C: 580±270 g/h; 37M: 635±440 g/h, P=0.63). Conclusion: Preliminary results suggest that consumption of a TRPM8 agonist in advance of passive heat stress may attenuate the sudomotor onset similarly to 1.5˚C water relative to 37˚C. However, the sweating response remains largely unaffected during passive heat stress between all three fluids assessed. Funding: This research was supported by Dr. Nicholas Ravanelli’s Natural Sciences and Engineering Research Council of Canada Discovery Grant (PIN#2022-05096). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
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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) | 0.000 | 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 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".