Browsing by Author "Poon ET-C"

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    Dietary Nitrate Supplementation and Exercise Performance: An Umbrella Review of 20 Published Systematic Reviews with Meta-analyses
    (Springer Nature Switzerland AG, 2025-03-14) Poon ET-C; Iu JC-K; Sum WM-K; Wong P-S; Lo KK-H; Ali A; Burns SF; Trexler ET; McMillan S; Olney R
    Background: Dietary nitrate (NO3−) supplementation is purported to benefit exercise performance. However, previous studies have evaluated this nutritional strategy with various performance outcomes, exercise tasks, and dosing regimens, often yielding inconsistent results that limit the generalizability of the findings. Objective: We aimed to synthesize the available evidence regarding the effect of NO3− supplementation on 11 domains of exercise performance. Methods: An umbrella review was reported in accordance with the Preferred Reporting Items for Overviews of Reviews guideline. Seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) were searched from inception until July 2024. Systematic reviews with meta-analyses comparing NO3− supplementation and placebo-controlled conditions were included. Literature search, data extraction, and methodological quality assessment (A Measurement Tool to Assess Systematic Reviews Assessing the Methodological quality of SysTemAtic Review [AMSTAR-2]) were conducted independently by two reviewers. Results: Twenty systematic reviews with meta-analyses, representing 180 primary studies and 2672 unique participants, met the inclusion criteria. Our meta-analyses revealed mixed effects of NO3− supplementation. It improved time-to-exhaustion tasks [standardized mean difference (SMD): 0.33; 95% confidence interval (CI) 0.19–0.47] with subgroup analyses indicating more pronounced improvements when a minimum dose of 6 mmoL/day (372 mg/day) and chronic (> 3 days) supplementation protocol was implemented. Additionally, ergogenic effects of NO3− supplementation were observed for total distance covered (SMD: 0.42; 95% CI 0.09–0.76), muscular endurance (SMD: 0.48; 95% CI 0.23–0.74), peak power output (PPO; SMD: 0.25; 95% CI 0.10 to 0.39), and time to PPO (SMD: − 0.76; 95% CI − 1.18, − 0.33). However, no significant improvements were found for other performance outcomes (all p > 0.05). The AMSTAR-2 ratings of most included reviews ranged from low to critically low. Conclusions: This novel umbrella review with a large-scale meta-analysis provides an updated synthesis of evidence on the effects of NO3− supplementation across various aspects of exercise performance. Our review also highlights significant methodological quality issues that future systematic reviews in this field should address to enhance the reliability of evidence. Clinical Trial Registration: This study was registered in the International Prospective Register of Systematic Review (PROSPERO) database (registration number: CRD42024577461).
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    Effects of carbohydrate, caffeine, and combined mouth rinses on physiological and perceptual responses during high-intensity interval exercise following a pre-exercise meal: a double-blinded, placebo-controlled, randomized crossover trial
    (Taylor and Francis Group, 2025-12-31) Suen MW-K; Sun F; Ali A; Poon ET-C
    Background Mouth rinsing with carbohydrate (CHO), caffeine (CAF), and their combined (CHO+CAF) solutions has been shown to enhance exercise performance. However, most previous studies were conducted under fasted conditions, which may not accurately reflect the typical practices of athletes who generally consume food before intense exercise or competition. This study examined the effects of CHO, CAF, and CHO+CAF mouth rinses on physiological and perceptual responses during high-intensity interval exercise (HIIE) following a pre-exercise meal. Methods Twelve recreationally active males (age: 23.4 ± 3.2 years) completed four HIIE trials involving 8 bouts of 1-min cycling at 85% of peak power output (PPO), separated by 1-min active recovery at 20% of PPO. Using a double-blinded randomized crossover design, participants rinsed with either 10% maltodextrin (CHO), 1.2% caffeine (CAF), 10% maltodextrin + 1.2% caffeine (CHO+CAF), or water (PLA) twice in each trial (after warm-up and interval 4). All solutions were taste-matched using the artificial sweetener sucralose. A standardized CHO-rich (1 g·kg−1 body weight) breakfast was provided an hour before testing. Results Ratings of perceived exertion were significantly different between conditions after interval 4 (CHO: 12.3 ± 1.6; CAF: 13.5 ± 2.2; CHO+CAF: 12.7 ± 1.7; PLA: 13.7 ± 2.4; 𝑝 = 0.049, 𝜂2 𝑝 = 0.21), but no significant effects of the mouth rinse conditions were observed on heart rate, blood glucose, blood lactate, affective valence, perceived activation, or affective responses (pleasure, arousal, and dominance) (all p > 0.05). Conclusion These findings suggest a limited ergogenic benefit of CHO and/or CAF mouth rinse through physiological and perceptual responses following sufficient food intake.