Abstract 598: Irisin, a Novel Hormone, and Its Response to Increasing Exercise Intensity in Young Healthy Subjects
Bibliographic record
Abstract
Introduction: Irisin, a recently discovered hormone, has been shown to induce white adipose tissue browning, enhancing energy expenditure and possibly mediating some of the beneficial effects of exercise. We aimed to estimate a) the timeframe of changes in plasma irisin levels after acute maximal exercise, b) the effect of different exercise intensities on irisin levels immediately post-exercise, and c) the effect of smoking (chronic and acute) on exercise-induced irisin release. Methods: a) 4 healthy subjects (22.5±1.73 years) underwent maximal exercise to attain maximal oxygen consumption (VO 2max ). Blood was drawn at pre-specified intervals to define the time curve of irisin changes over a 24-hr period; b) 35 healthy, non-smoking (23.0±3.3 years) men and women (n=20/15) underwent three exercise protocols ≥48 hrs apart, in random order: 1) maximal intensity (VO 2max ), 2) relative intensity (70% VO 2max , 10 mins); and 3) absolute intensity (75W output, 10 mins). Blood was drawn immediately pre- and 3 mins post-exercise; c) In 20 smokers irisin levels were measured pre- and 3 mins post-maximal exercise after 12 hrs abstinence from smoking on two separate days 1) continued abstinence (chronic smoking) and 2) after smoking one cigarette pre-exercise (acute smoking), compared to 10 non-smokers. Results: a) Irisin levels increased by 35% 3 mins post-exercise, then dropped and remained constant; b) Irisin levels post-exercise were significantly higher than pre-exercise after all intensities (all, P<.001). Post-pre exercise differences in irisin levels were significantly different between exercise intensities (P=.001), with the greatest increase after maximal intensity (P=.004 vs. relative, and absolute). Higher VO 2max correlated with a greater post-pre exercise difference in irisin levels after maximal exercise; c) Smoking study analyses are underway. Conclusions: Plasma irisin levels were acutely elevated in response to exercise, with a greater increase after maximal exercise. Higher VO 2max was associated with greater irisin release. These findings suggest that irisin release could be a function of muscle energy demand. Future studies need to determine the underlying mechanisms of irisin release and explore irisin’s therapeutic potential.
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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 | 0.001 |
| 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) | 0.002 | 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".