LunHab: interactive effects of a 10 day sustained exposure to hypoxia and bedrest on aerobic exercise capacity in male lowlanders
Bibliographic record
Abstract
New Findings What is the central question of this study? What are the distinct and interactive effects of a 10 day exposure to hypoxia and horizontal bedrest on the whole‐body peak oxygen uptake and on the regional cerebral and skeletal muscle tissue oxygenation during upright cycle ergometry in male lowlanders? What is the main finding and its importance? A 10 day sustained exposure to hypoxia aggravates the bedrest‐induced reduction in peak oxygen uptake during dynamic exercise engaging large muscle groups, but mitigates the skeletal muscle oxidative capacity impairment elicited by bedrest. The study examined the interactive effects of a 10 day exposure to hypoxia and bedrest on the whole‐body peak oxygen uptake ( ) during maximal exercise and on skeletal muscle and cerebral oxygenation during submaximal exercise. Nine males underwent three 10 day confinements, in a Latin‐square order, as follows: (i) a normoxic bedrest [NBR; partial pressure of inspired O 2 ( ) = 134.2 ± 0.7 mmHg]; (ii) a hypoxic bedrest (HBR; = 102.9 ± 0.1 mmHg at day 1, 91.5 ± 1.2 mmHg at days 3–10); and (iii) a hypoxic ambulation (HAMB; as in HBR). Before, 1 (R+1) and 3 days (R+3) after each confinement, subjects performed exhaustive, incremental‐load and moderate‐intensity constant‐load (CLTs) cycle‐ergometry trials, while breathing either room air or a hypoxic gas mixture. During the CLTs, changes in the regional oxygenation of the cerebral frontal cortex and the vastus lateralis and intercostal muscles were monitored with near‐infrared spectroscopy. At R+1, the confinement‐related impairment in was greater after HBR than after NBR or HAMB, regardless of whether the trial was performed in room air or hypoxia (HBR, −16.2%; NBR, −8.3%; HAMB, −4.1%; P = 0.001). During the CLTs, bedrest aggravated the exercise‐induced reduction in locomotor and respiratory muscle oxygenation ( P ≤ 0.05); an effect that was less after HBR than after NBR ( P ≤ 0.05). The hypoxic exercise‐induced cerebral vasodilatory response was blunted by HBR, probably because of the marked hyperventilation‐dependent hypocapnia, attendant to the sustained hypoxic stimulus. Hence, short‐term exposure to hypoxia potentiates the reduction in , but it mitigates the impairment in skeletal muscle oxidative capacity induced by bedrest.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".