Exercise training mitigates the deleterious effects of experimental bed rest on intraindividual variability of executive functioning in older adults: A randomised controlled trial
Bibliographic record
Abstract
Abstract Background In older adults, bed rest can occur because of chronic conditions, injury, surgery, or hospitalization. Extreme levels of physical inactivity due to bed rest initiate a downward spiral in several body systems. Exercise is a countermeasure to many of these changes; nonetheless, little is known about the effect of exercise on older adults’ cognition during bed rest. We thus examined the effects of exercise on the intraindividual variability (IIV) of cognitive performance in older adults exposed to 14 days of experimental 6° head‐down bed rest (HDBR) and whether sex moderates its effects. We chose IIV as our outcome measure because it is more sensitive than traditional summary scores of cognitive performance, albeit no studies have explored exercise effects on older adults’ IIV submitted to bed rest. Method A non‐blinded, parallel‐group, randomised controlled trial. Twenty‐three healthy older adults aged 55‐65 were randomised to: 1) 14 days of HDBR (CON); or 2) 14 days of HDBR with daily aerobic and strength exercise (EX). Data were collected at baseline, HDBR completion, and end of seven‐day‐recovery. The National Institutes of Health Toolbox Cognitive Battery assessed executive function (Flanker Incongruent and Congruent and Dimensional Change Card Sort) and processing speed (Pattern Comparison). IIV was indexed by intraindividual coefficient of variation (ICV) and residual intraindividual standard deviation (R‐ISD), with R‐ISD as our primary measure of interest. Linear mixed models assessed group differences and the moderator role of sex. Result At HDBR completion, EX had significantly lower (better) Flanker incongruent ICV (Estimated mean difference = ‐0.10, 95%CI ‐0.19;‐0.003, p = 0.022) and R‐ISD (Estimated mean difference = ‐3.63, 95%CI ‐6.10;‐1.17, p = 0.005) vs. CON. Sex moderated the effect of exercise; females in EX had significantly lower Flanker incongruent ICV vs. CON (Estimated mean difference = ‐0.23; 95%CI ‐0.34;‐0.12, p<0.001). At the end of the seven‐day recovery, EX had significantly lower Flanker incongruent R‐ISD vs. CON (Estimated mean difference = ‐3.11, 95%CI ‐5.70;‐0.052, p = 0.019). Summary scores and processing speed IIV changes were not statistically significant (ps>0.05). Conclusion Exercise during HDBR preserved executive functioning, especially in females. Our findings support the delivery of exercises to older adults during bed rest to preserve their cognitive function.
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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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.003 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".