An Exploratory Investigation of Heart Rate Variability in Response to Exercise Training and Detraining in Young and Middle-Aged Men
Bibliographic record
Abstract
We examined heart rate (HR) and heart rate variability (HRV) in young and middle-aged men after a period of detraining that immediately followed the completion of an exercise training program. Eight young (27.8 ± 3.8 years) and ten middle-aged (41.9 ± 3.8 years) men were randomly assigned to complete an 8-week exercise training program that included either aerobic (young: n = 3; middle-aged: n = 2), resistance (young: n = 3; middle-aged: n = 3), or combined (aerobic/resistance) (young: n = 2; middle-aged: n = 5) exercise. Thereafter, participants ceased all planned exercise training activities during an 8-week detraining period. Resting HR and HRV were assessed at baseline, after exercise training, and after detraining. An analysis of mean differences between age groups at each time-point revealed a significantly higher standard deviation of normal RR intervals (SDNN), square root of the mean of squared differences between successive RR intervals (RMSSD), high-frequency (HF) band (0.15–0.40 Hz), and cardiac vagal index (CVI) in young participants when compared to middle-aged participants at baseline (p ≤ 0.019) and after detraining (p ≤ 0.045), but not after the 8-week exercise training intervention (p ≥ 0.057). Additionally, in middle-aged participants, we observed a significant negative association between the percent change in HRV indices (RMSSD, HF, and CVI) and systolic blood pressure in response to detraining (p < 0.05). In conclusion, young participants had higher levels of HRV indices at baseline, reflecting greater cardiac vagal modulation when compared to middle-aged participants. We showed that these age-related differences in HRV are diminished following exercise training but are reestablished following 8 weeks of detraining. Given that age-related attenuations in HRV may reflect changes in cardiovascular health, it is important to further investigate the relationships between HRV, exercise training and detraining, aging, and the risk of poor health outcomes.
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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) | 0.001 | 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".