The Effects of Acute and Chronic Beetroot Juice Supplementation on Exercise Economy and Time Trial Performance in Recreationally Active Females
Notice bibliographique
Résumé
Introduction Beetroot juice (BRJ) is a nutritional supplement that has received widespread attention over the last decade. Dietary nitrate (NO 3 − ) reduces the oxygen cost of submaximal exercise and improves performance in recreationally active males both acutely and chronically. The ergogenic effects of BRJ have been attributed to its high nitrate content. However, the evidence supporting the effects of BRJ in females is lacking. Purpose To investigate the effects of acute and chronic BRJ supplementation on submaximal exercise oxygen uptake (VO 2 ) and time trial performance (~30 min) in recreationally active females. Methods Using a double‐blind, randomized, crossover design, 12 recreationally active females who were taking oral contraceptives supplemented acutely (2.5 hr) and chronically (8 days) with 280 mL BRJ/day (~26 mmoles NO 3 − ) or the same volume of a nitrate‐free BRJ (PLA). All trials were conducted at the same time in the morning, and there was a 9 ± 0.7 day washout period between trials. Subjects arrived to the laboratory, a baseline blood sample was drawn, a standardized breakfast including 140 mL BRJ or PLA was provided, and a second blood sample was drawn 2 hr later. Blood samples were analyzed for plasma NO 3 − and nitrite (NO 2 − ), as well as estrogen and progesterone. The subjects then cycled for 10 min at 50% and 10 min at 70% VO 2peak , and completed a 4 kJ/kg body mass time trial (TT). Ratings of perceived exertion (RPE), heart rate (HR) and revolutions per minute (rpm) were recorded at 5 min intervals during the submaximal cycling protocol. RPE, HR, rpm, and power output (PO) were recorded as the subjects completed each 20% of the TT. Results There were no significant differences in estrogen or progesterone levels between trials. Plasma NO 3 − concentrations increased significantly following BRJ supplementation compared to PLA (Acute PLA: 44 ± 3 and Chronic PLA, 41 ± 3 μM vs. Acute BRJ, 761 ± 31 and Chronic BRJ, 1091 ± 58 μM). Similarly, plasma NO 2 − increased significantly following BRJ supplementation compared to PLA (Acute PLA, 265 ± 25 and Chronic PLA, 278 ± 26 nM vs. Acute BRJ, 753 ± 84 and Chronic BRJ, 729 ± 101 nM). There was no significant difference in mean VO 2 at 50% VO 2peak (Acute PLA, 1254 ± 45: Acute BRJ, 1259 ± 46: Chronic PLA, 1267 ± 45: Chronic BRJ, 1252 ± 42 mL/min O 2 ) and 70% VO 2peak (Acute PLA, 1804 ± 60: Acute BRJ, 1791 ± 53: Chronic PLA, 1814 ± 54: Chronic BRJ, 1789 ± 54 mL/min O 2 ) between trials. No significant difference was found for rpm, HR, or RPE at 50% or 70% VO 2peak . TT performance was unaffected by BRJ (Acute PLA, 1709 ± 75: Acute BRJ, 1813 ± 97: Chronic PLA, 1751 ± 78: Chronic BRJ, 1791 ± 102 s). No significant difference was found for HR, RPE, or PO between conditions throughout the time trial. Conclusion BRJ did not reduce submaximal exercise oxygen uptake or improve aerobic TT performance in recreationally active females. Future studies should investigate the potential sex differences that may exist with respect to the ergogenic effects of BRJ supplementation. Support or Funding Information Natural Science and Engineering Research Council of Canada (NSERC) This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,000 |
| 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) | 0,003 | 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 ».