Ventilatory and cerebrovascular responses to exercise in lowlander children acclimatizing to high‐altitude
Notice bibliographique
Résumé
Abstract Maturational differences in chemoreception and cerebral blood flow are evident at sea‐level, yet the age‐related comparisons in cardiopulmonary and cerebrovascular responses to high‐altitude exercise are unknown. Lowland living children (n = 8: 7–14 years) and adults (n = 10: 23–44 years) performed incremental cycle exercise to exhaustion at sea‐level and following 6 days at 3800 m. Ventilation (VE), end‐tidal carbon dioxide () and pulse oximetry estimation of oxygen saturation (), as well as cerebrovascular measures of middle (MCA) and posterior (PCA) cerebral artery velocities (v) were measured at rest and throughout exercise. At high‐altitude, both children and adults showed comparable increases in VE and reductions in and at rest (altitude: P < 0.001, group: P ≥ 0.22). During exercise, VE increased at high‐altitude compared to sea‐level (P < 0.001), with no significant group differences (P = 0.134). Adults exhibited greater elevations in at sea‐level compared to children (P = 0.023), but no significant group differences were present at high‐altitude (P = 0.144). reductions during high‐altitude exercise were greater in adults than in children (80.4 ± 4.4% versus 85.8 ± 3.5%, P = 0.002), with both groups showing significant declines from sea‐level (P < 0.001). No group differences in exercise induced changes in MCAv (P = 0.159) or PCAv (P = 0.674) were present at sea‐level, but at high‐altitude, children displayed greater MCAv (82.8 ± 9.7 versus 71.6 ± 7.8 cm s−1, P = 0.014) and PCAv responses versus adults (61.8 ± 8.1 versus 46.7 ± 10.0 cm s−1, P = 0.001). Exposure to high‐altitude resulted in a greater cerebral blood velocity response during exercise in children, despite a greater preservation of oxygenation and a comparable degree of hypocapnia, suggesting differential thresholds of O2 and CO2 prioritization. image Key points Children and adults exhibit distinct ventilatory and cerebrovascular responses to exercise, which may influence their acclimatization to high‐altitude environments. Children (ages 7–14 years) and adults (ages 23–44 years) were brought from sea‐level to high‐altitude (3800 m), where changes in cardiopulmonary and cerebrovascular responses were assessed during incremental exercise. At high‐altitude, both groups showed comparable increases in ventilation and similar levels of hypocapnia. However, children showed a lower magnitude of peripheral oxygen desaturation during high‐altitude exercise. Despite better preservation of oxygenation, children showed a greater increase in cerebral blood velocity during exercise, suggesting an increased prioritization of oxygen delivery to the brain. These results improve our understanding of the age‐related differences in cerebrovascular sensitivity during exercise at sea‐level and high‐altitude, indicating a dominance of hypoxic vasodilatation and reduced sensitivity to endogenous carbon dioxide during exercise.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».