Cold-water foot immersion and physiological strain of adults with coronary artery disease during hot and humid heat exposure
Bibliographic record
Abstract
Introduction: Heat extremes are associated with a greater risk of adverse cardiovascular outcomes, especially among adults with coronary artery disease. While air-conditioning provides exceptional protection during heat extremes, it is neither sustainable nor widely accessible. Cold-water foot immersion reduces physiological heat strain in healthy young adults but its effect in more vulnerable populations remains unknown. Objective and hypotheses: This study aims to identify the effect of cold-water foot immersion on markers of physiological heat strain in adults with coronary artery disease. We hypothesized that cold-water foot immersion would reduce physiological heat strain when used on its own and that this effect would be greater when combined with an electric fan. Methods: 17 adults living with stable coronary artery disease (2 females/15 males; 67±8 years) were exposed to a 38°C, 60% relative humidity environment for 3 hours on three separate, randomized occasions: i) no cooling (control; CON); ii) cold-water foot immersion (20 min of immersion each 30 min, ~30 cm in water kept at ~18°C; FI); iii) cold-water foot immersion and fan use (FI+FAN). Rectal and skin temperatures, heart rate (5-lead ECG), and whole-body sweat loss (change in nude weight) were measured. Results: The increase in rectal temperature did not differ between conditions (CON: 0.40±0.24°C, FI: 0.41±0.29°C, and FI+FAN: 0.36±0.22°C; p≥0.49). The increase in skin temperature was reduced with FI and FI+FAN compared to CON (CON: 4.9±0.8°C, FI: 4.1±1.2°C, and FI+FAN: 4.3±0.8°C; p≤0.01), with no difference between FI and FI+FAN (p=0.15). Similarly, the increase in heart rate was reduced with FI and FI+FAN compared to CON (CON: 8±6 bpm, FI: 4±6 bpm, and FI+FAN: 3±6 bpm; p≤0.01), with no difference between FI and FI+FAN (p=0.45). Sweat loss was also reduced by FI and FI+FAN compared with CON (CON: 823±114 g, FI: 544±174 g, and FI+FAN: 671±255 g; p≤0.03), with sweat loss during FI sweat loss being lower than during FI+FAN (p=0.03). Conclusion: The results show that cold-water foot immersion, used alone or in combination with an electric fan, reduces the increase in heart rate and whole-body sweat loss of adults living with coronary artery disease exposed to a hot and humid environment for 3 hours. This could be linked to the lower increase in skin temperature with foot immersion. National Health and Medical Research Council of Australia (APP1147789). 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 | 0.001 |
| 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".