Individual differences in compensatory vasodilation impact exercise performance
Notice bibliographique
Résumé
INTRODUCTION It is often stated that oxygen delivery (O 2 D) demand matching is tightly coupled during submaximal exercise. Traditional research approaches have ignored the potential for unique individual response heterogeneity in this model. Previously when we challenged exercising muscle O 2 D by having participants perform progressive exercise to peak with exercising forearm perfusion pressure reduced, we found individuals inherently differed in their vasodilatory response to an O 2 D challenge, with some having compensatory vasodilation while others did not. PURPOSE To test the hypothesis that both compensatory and non‐compensatory vasodilation phenotypes are evident in the face of a sudden compromise to exercising muscle O 2 D. Furthermore, that non‐compensators suffer greater impacts on exercise performance as a result. METHODS 19 healthy male participants (21.8 ± 2.0 yrs) each completed 3 rhythmic isometric forearm exercise protocols separated by 24 hours. Day 1: Participants completed progressive exercise to peak. The intensity associated with 70% peak forearm vascular conductance (FVC: ml/min/100mmHg) was identified. Day 2: Participants performed steady state exercise at the 70% peak FVC intensity. This ensured that the vasodilatory reserve available to respond to a sudden challenge to O 2 D was the same across participants. A perfusion pressure‐induced challenge to O 2 D, which decreases local pressure by ~30 mmHg, was then introduced during the exercise. Day 3: Peak vasodilatory capacity was assessed, as well as perfusion and vasodilatory kinetics during exercise with a perfusion pressure challenge. Forearm blood flow (FBF: ml/min), mean arterial blood pressure (MAP: mmHg); and O 2 D (ml/O 2 /min) were measured throughout. RESULTS Day 2: 11 participants responded with compensatory vasodilation when steady state O 2 D was challenged (FVC RELAX : 660 ± 134 vs. 530 ± 124 ml/min/100mmHg, P<0.001) while 8 participants yielded no compensatory response (FVC RELAX : 667 ± 167 vs. 663 ± 165 ml/min/100mmHg, P=0.8). Steady state FBF, O 2 D, and oxygen consumption (VO 2 ) were all compromised in the non‐compensators (P<0.05), while MAP remained similar between vasodilator response groups (P>0.08). As a result of such compromises, exercise tolerance in a perfusion pressure challenged position was reduced to a greater extent in the non‐compensators compared to an unchallenged position (−92 ± 73 vs. −11 ± 37 N, P=0.01). Day 1: There was no difference in exercise performance (230 ± 26 vs. 245 ± 27 N, P=0.2) nor the intensity associated with 70% peak FVC (168 ± 33 vs. 158 ± 23 N, P=0.4) between non‐compensators and compensators. Day 3: Peak vasodilatory capacity was not different between compensatory and non‐compensatory vasodilators (956 ± 236 vs. 920 ± 364 ml/min/100mmHg, P=0.8). There was no difference in the FBF and FVC kinetic responses to an absolute intensity with a perfusion pressure challenge (all P>0.05). CONCLUSIONS Vasodilatory response phenotypes exist which determine inter‐individual differences in O 2 D and impact exercise performance. A non‐compensation response is not explained by differences in vasodilatory capacity, peak exercise capacity or work rate at which 70% peak vasodilation response occurred. Support or Funding Information NSERC
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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 | 0,001 | 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) | 0,004 | 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 ».