Myocardial Dysfunction And Cardiac Performance Changes In Marathon Runners Monitored Using Ballistocardiography
Bibliographic record
Abstract
Previous research using echocardiography has shown that marathon running alters cardiac performance (i.e. cardiac cycle events) suggesting a transient myocardial dysfunction. Furthermore, it has been shown that an interaction between intensity and duration play a critical role in this response. We hypothesized that differences in cardiac performance between full and half-marathon could be detected using ballistocardiography (BCG). PURPOSE: To measured the mechanical function of the heart in marathon runners using non-invasive BCG. METHODS: A group of recreational runners with no known cardiovascular disease completed a full (FM; N=19; age=46.3±5.2yr; time=3:49±24 min) or half-marathon (HM; N=6; age=39.7±7.9yr; time=1:52±12 min). While lying supine under resting conditions, each runner had a factory calibrated BCG sensor, which recorded the hearts vibration and a Lead II EKG, placed over the sternum 1cm above the xiphoid process. A 30-sec BCG and EKG was recorded and stored for later analysis. A total of 15 BCG waveforms (heart beats) were analyzed for each runner pre, post, and on D1, D2, D3, and D7 post-marathon. RESULTS: When corrected for heart rate the repeated-measures ANOVA showed statistical (p≤0.05) differences between groups and over time for both systolic and diastolic timing events. Isovolumic contraction time was significantly increased pre- to post-marathon for the FM (132%) and HM (173%) and remained elevated at D7 (91% and 106% respectively). Acceleration time was increased pre- to post-marathon for both groups and was significantly longer for the FM (25%) and HM (80%). Left ventricular ejection time was 32% (FM) and 41% (HM) longer post-marathon, and rapid ejection time demonstrated a similar pattern (30% and 68% longer, respectively). Diastolic events were also affected post-marathon, with isovolumic relaxation time being significantly longer pre- to post-marathon in FM (30%) and HM (62%), and remained elevated in the HM until D3. Ventricular relaxation time (i.e., mitral valve open to early diastolic filling) was longer after the marathon (FM 40%; HM 68%), and remained elevated in the HM runners at D7 (24%). Diastolic timing was unchanged pre-to post-marathon, but increased and remained elevated at D7 (20%). CONCLUSIONS: These data suggest that: 1) altered myocardial function occurred after both the HM and FM as reflected by changes in systolic and diastolic timing; 2) greater cardiac changes occurred in the HM runners post-marathon; 3) transient changes in myocardial dysfunction can last up to D7 post-marathon, and 4) systolic and diastolic cardiac events can be monitored with BCG. Financial Support: CIHR, NSERC Canada
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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 | 0.000 |
| 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 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".