Physical Activity and Sedentary Behaviour Thresholds for Secondary Prevention of Coronary Heart Disease: Morbidity Survival Tree Analysis
Bibliographic record
Abstract
BACKGROUND: There are no diagnosis-specific guidelines for moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) for coronary heart disease (CHD). This study aimed to identify thresholds of MVPA and SB associated with cardiovascular events. METHODS: This cohort study included individuals with CHD. MVPA and SB were self-reported, and health registries identified cardiovascular events in the years 2006-2022. Survival tree analyses identified thresholds of time associated with the risk of cardiovascular events. Thresholds were explored with the use of Cox regression models. RESULTS: There were 40,156 Australians, mean age 70 years, 62% men. Over a median 8.3 years, 3260 nonfatal cardiac events, 5161 total cardiac events, and 14,383 major adverse cardiovascular events (MACE) occurred. Thresholds for MVPA were 122 min/wk for nonfatal cardiac events and 94 min/wk for total cardiac events and MACE. Meeting MVPA thresholds was associated with an 18% lower risk for nonfatal cardiac events, 29% lower risk of total cardiac events, and 23% lower risk of MACE than not reaching the thresholds. Thresholds for SB were 4 and 10 h/d, respectively, for risk of total cardiac events and MACE. SB below thresholds was associated with a 14% lower risk of total cardiac events and an 18% lower risk of MACE. There were sex-specific thresholds for MVPA and SB. CONCLUSIONS: To lower cardiovascular event risk, identified MVPA thresholds were lower (94-122 min/wk) than the public health guidelines (150 min/wk) in individuals with CHD. The SB thresholds associated with a lower risk of total cardiac events and MACE varied from 4 to 10 h/d.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.008 | 0.014 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".