Effect Of Caffeine On Ratings Of Perceived Exertion (rpe) And Electroencephalography (eeg) Activity During Exercise
Bibliographic record
Abstract
One of the explanations for the ergogenic effect caffeine has on endurance performance is the reduction in RPE during exercise. The physiological mechanisms accounting for the decrease in RPE remain unclear. PURPOSE: To examine the influence of caffeine on RPE and EEG during 30 min of continuous cycling. EEG was measured to determine the degree of central nervous system functioning during exercise and possibly provide an explanation for any EEG differences due to caffeine ingestion. METHODS: 9 subjects unaccustomed to cycling performed a VO2peak test using a cycle ergometer (mean VO2peak = 35.8 ± 8.7 ml·kg-1·min-1). Subjects then returned for 2, 30-min cycling tests performed on successive days at a workload equal to approximately 60% VO2peak. Prior to the 30-min tests subjects either ingested caffeine (3 mg·kg-1) or a placebo, with the order randomized and the experimenters blinded to order. Fifteen channels of EEG were recorded according to the International 10-20 system of electrode placement. Recordings occurred prior to cycling during a warm-up, at minutes 4-5, 9-10, 14-15, 19-20, 24-25, 29-30, and during cool down. Heart rate (HR) and RPE were also collected during these periods. RESULTS: Peak RPE during the placebo trial was 16.8 ± 2.9 and during the caffeine trial RPE reached 15.8 ± 1.9. While RPE significantly increased in both trials (p = 0.002) the differences between the trials only approached significance (p = 0.074). No significant differences were observed for heart rate between the placebo and caffeine trials at any point before (102.4 ± 9.3 and 100.9 ± 13, respectively), during (peak HR 172.2 ± 18.1 and 173 ± 18.7, respectively), or after (158 ± 9.9 and 159 ± 8.5, respectively) the cycle ergometry test (p = 0.271). The expected EEG response to exercise was observed with an increase in delta wave activity and a decrease in higher frequencies such as beta1 activity (F(10,1131) = 8.326; p=0.00). No significant differences were observed for any EEG variables between the placebo and caffeine trials (p = 0.794). CONCLUSION: The absence of any differences in EEG following caffeine ingestion do not support a central nervous system basis for RPE decreases associated with caffeine ingestion during exercise. However, the findings from this study are limited by the small sample size.
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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 | 0.002 |
| 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".