DAILY EXERCISE DOES NOT ALTER CEREBRAL BLOOD FLOW REGULATION DURING TILT IN OLDER ADULTS AFTER TWO WEEKS OF BEDREST
Bibliographic record
Abstract
Abstract Bedrest is associated with cardiovascular and cerebrovascular changes that are linked to a greater prevalence of orthostatic intolerance; however, much of what we know from bedrest trials comes from young adults. How older adults respond to extended periods of activity restriction is not well understood. The current work tested the hypothesis that impaired control of cerebral blood flow in older adults following bedrest could be attenuated by regular exercise. Twenty-two older adults (55-65 years, 11 women) participated in a randomized controlled trial involving 14 days of continuous 6-degree head-down bedrest. The cohort was randomized to an exercise intervention (EX), involving daily aerobic, high-intensity interval, and resistance training, or a control group (CON), involving passive manual therapy. Cerebral blood flow velocity, cardiac output, and arterial blood pressure were measured continuously during a passive 80-degree head-up tilt protocol for up to 15 minutes. Responses in the cerebral and peripheral vascular beds were quantified by vascular resistance (cerebral: resistance area product (RAP); peripheral: total peripheral resistance (TPR)). Following bedrest, both supine RAP and TPR were elevated (p< 0.01), with no effect of exercise training. In addition, the number of participants who could not complete 15 minutes of tilt increased from 3 to 15 (8 EX, 7 CON). In these non-finishers, RAP dropped ~20% and TPR dropped ~15% during the final 2 minutes of tilt, with no difference between groups. These data suggest that multimodal exercise training is insufficient to prevent changes in cardiovascular and cerebrovascular regulation in older adults observed during 14-day bedrest.
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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) | 0.001 | 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".