Journal of the International Society of Sports Nutrition最新文献

{"title":"Muscle contraction time after caffeine intake is faster after 30 minutes than after 60 minutes.","authors":"Paweł Pakosz, Mariusz Konieczny, Przemysław Domaszewski, Tomasz Dybek, Oscar García-García, Mariusz Gnoiński, Elżbieta Skorupska","doi":"10.1080/15502783.2024.2306295","DOIUrl":"10.1080/15502783.2024.2306295","url":null,"abstract":"<p><strong>Background: </strong>This study aimed to determine the optimal time point, either 30 or 60 minutes, at which muscle reactivity to caffeine administration is highest. Unlike previous studies that focused on the nervous system response, we employed tensiomyography (TMG) to directly assess the effects of caffeine on muscle fibers.</p><p><strong>Methods: </strong>TMG measurements were performed on the gastrocnemius medialis muscle of 42 male athletes who regularly consumed caffeine. Participants received a dose of 6 mg/kg body weight and TMG measurements were taken prior to caffeine intake, as well as 30 and 60 minutes afterward.</p><p><strong>Results: </strong>Analysis of TMG parameters including time to contraction (Tc), time delay (Td), and maximal displacement (Dm) revealed that muscles exhibited faster contractions and greater stiffness at the 30-minute mark compared to both pre-caffeine intake and the 60-minute time point. Time exerted a significant main effect on Tc (F(2, 246) = 12.09, <i>p</i> < .001, ή2p = 0.09), Td (F(2, 246) = 3.39, <i>p</i> = .035, ή2p = 0.03), and Dm (F(2, 246) = 6.83, <i>p</i> = .001, ή2p = 0.05), while no significant effect of body side was observed.</p><p><strong>Conclusions: </strong>The findings indicate that muscle contraction time (Tc) and delay time (Td) are influenced by the time elapsed since caffeine ingestion, with the fastest responses occurring after 30 minutes. Additionally, a systemic effect of caffeine was observed, as there were no discernible differences in measurements between the two sides of the body. TMG proves to be an effective noninvasive method for assessing muscle responses following caffeine administration.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2306295"},"PeriodicalIF":4.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10802797/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139491349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of quercetin and citrulline on cycling time trial performance.","authors":"Jennifer A Kurtz, Jacob Grazer, Kathryn Wilson, Rafaela G Feresin, J Andrew Doyle, Ryan Middleton, Emma Devis, Trisha A VanDusseldorp, Kimberly Fasczewski, Jeff Otis","doi":"10.1080/15502783.2024.2416909","DOIUrl":"10.1080/15502783.2024.2416909","url":null,"abstract":"<p><strong>Background: </strong>There is growing interest in the use of nutrition and dietary supplements to optimize training and time-trial (TT) performance in cyclists. Separately, quercetin (QCT) and citrulline (CIT) have been used as ergogenic aids to improve oxygen (VO₂) kinetics, perceived effort, and cycling TT performance. However, whether the combination of QCT and CIT can provide additive benefits and further enhance cycling performance production is currently unknown.</p><p><strong>Methods: </strong>We examined 28-days of QCT + CIT supplementation on TT performance and several performance measures (i.e. mean power, VO₂, respiratory exchange ratio (RER), and rate of perceived exertion (RPE)). Forty-eight highly trained cyclists were assigned to one of four supplementation groups: (1) QCT + CIT (QCT: 500 mg, CIT: 3000 g), (2) QCT (500 mg), (3) CIT (3000 mg), or (4) placebo (3500 mg of a zero-calorie flavored crystal light package). Supplements were consumed two times per day for 28 consecutive days. Participants performed a 20-km cycling time-trial race, pre- and post-supplementation to determine the impact of the combined effects of QCT + CIT.</p><p><strong>Results: </strong>There were no potential benefits of QCT +CIT supplementation on TT performance and several performance measures. However, there was an improvement in VO₂ from pre-to-post-supplementation in QCT (<i>p</i>  = 0.05) and CIT (<i>p</i>  = 0.04) groups, but not in the QCT+CIT and PL groups.</p><p><strong>Conclusions: </strong>QCT + CIT does not seem beneficial for 20-km TT performance; further exploration with a focus on an increase in cycling duration or QCT+CIT combined with additional polyphenols may amplify any perceived bioactive or metabolic effects on cycling performance. The efficacy of QCT + CIT supplementation to improve cycling performance remains ambiguous.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2416909"},"PeriodicalIF":4.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11488173/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142468709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acute effects of various doses of nitrate-rich beetroot juice on high-intensity interval exercise responses in women: a randomized, double-blinded, placebo-controlled, crossover trial.","authors":"Zhang Jiaqi, Dai Zihan, Stephen Heung-Sang Wong, Zheng Chen, Eric Tsz-Chun Poon","doi":"10.1080/15502783.2024.2334680","DOIUrl":"10.1080/15502783.2024.2334680","url":null,"abstract":"<p><strong>Background: </strong>This study investigated the acute effects of various doses of nitrate-rich beetroot juice on the responses to high-intensity interval exercise in women.</p><p><strong>Methods: </strong>A double-blinded, randomized, placebo-controlled, crossover trial was conducted with 13 recreationally active young women (age = 23 ± 2 years). All participants performed interval exercise (8 × 1-min bouts of cycling at 85% of peak power output [PPO] interspersed with 1-min active recovery at 20% of PPO) 2.5 h after consumption of the randomly assigned beetroot juice containing 0 mmol (placebo), 6.45 mmol (single-dose), or 12.9 mmol (double-dose) <math><msubsup><mrow><mrow><mi>N</mi><mi>O</mi></mrow></mrow><mn>3</mn><mo>-</mo></msubsup></math>. The heart rate (HR), blood pressure, blood lactate, blood glucose, oxygen saturation, rating of perceived exertion (RPE), and emotional arousal were assessed.</p><p><strong>Results: </strong>Nitrate supplementation significantly altered the HR and RPE responses across the three trials. The mean HR was lower in the single- and double-dose groups than in the placebo control group during both work intervals and recovery periods, as well as across the overall protocol (all <i>p</i> < .05). The mean RPE was lower in the single- and double-dose groups than in the control group during recovery periods and across the overall protocol (all <i>p</i> < .001). However, there was no significant difference in either HR or RPE between the single- and double-dose groups at any time point.</p><p><strong>Conclusions: </strong>Acute nitrate ingestion led to significant decreases in the mean HR and RPE during high-intensity interval exercise, but no additional benefit was observed with higher nitrate content. These findings may assist practitioners in implementing more effective nitrate supplementation strategies during high-intensity interval exercise.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2334680"},"PeriodicalIF":5.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10977014/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140293878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of a sugar-free amino acid-containing electrolyte beverage on 5-kilometer performance, blood electrolytes, and post-exercise cramping versus a conventional carbohydrate-electrolyte sports beverage and water.","authors":"Mason C McIntosh, Bradley A Ruple, Nicholas J Kontos, Madison L Mattingly, Christopher M Lockwood, Michael D Roberts","doi":"10.1080/15502783.2023.2296888","DOIUrl":"10.1080/15502783.2023.2296888","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Objective: &lt;/strong&gt;The purpose of this study was to examine the acute effects of a multi-ingredient, low calorie dietary supplement (MIDS, XTEND® Healthy Hydration) on 5-kilometer (5-km) time trial performance and blood electrolyte concentrations compared to a carbohydrate-electrolyte beverage (CE, GATORADE® Thirst Quencher) and distilled water (W).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;During visit 1 (V1), participants (10 men and 10 women, 20-35 years old, BMI ≤ 29 kg/m&lt;sup&gt;2&lt;/sup&gt;, recreationally active) reported to the laboratory whereby the following tests were performed: i) height and weight measurements, ii) body composition analysis, iii) treadmill testing to measure maximal aerobic capacity, and iv) 5-km time trial familiarization. The second visit (V2) was one week after V1 in the morning (0600 - 0900) and participants arrived 12-14 h fasted (no food or drink). The first battery of assessments (V2-T1) included nude body mass, urine specific gravity (USG), a profile of mood states (POMS) questionnaire, and the completion of a visual analogue scale (VAS) questionnaire to quantify cramping. Then heart rate (HR), blood pressure (BP), total body hydration (via bioelectrical impedance spectroscopy [BIS]) were examined. Finally, a measurement of blood markers via finger stick was performed. Participants consumed a randomized beverage (16 fl. oz. of MIDS, 16 fl. oz. of W, or 16 fl. oz. of CE) within 3 min followed by a 45-min rest. Following the rest period, a second battery (V2-T2) was performed whereby participants' USG was assessed and they completed the POMS and VAS questionnaires, and HR, BP, and blood markers were measured. The participants then performed a 5-km treadmill time trial. Immediately following the 5-km time trial, participants completed a third testing battery (V2-T3) that began with blood markers, HR and BP assessments, followed by nude body weight assessment, and the POMS and VAS questionnaires. After 60 min, a fourth battery (V2-T4) was performed that included HR, BP, and blood markers. After sitting quietly for another 60 min a fifth battery assessment was performed (V2-T5) that included participants' USG, POMS and VAS questionnaires, HR, BP, blood markers, and total body hydration. Visits 3 (V3) and 4 (V4) followed the same protocol except a different randomized drink (16 oz. of CE, MIDS, or W) was consumed; all of which were separated by approximately one week.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;No differences occurred between conditions for 5-km time trial completion, indirect calorimetry outcomes during 5-km time trials, USG, or nude mass measurements (&lt;i&gt;p&lt;/i&gt; &gt; 0.05 for all relevant statistical tests). However, blood potassium and the sodium/potassium ratio displayed significant interactions (&lt;i&gt;p&lt;/i&gt; &lt; 0.05), and post hoc testing indicated these values were better maintained in the MIDS versus other conditions. Post-exercise cramp prevalence was greater in the CE (&lt;i&gt;p&lt;/i&gt; &lt; 0.05) and trended higher with W (&lt;i&gt;p&lt;","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2296888"},"PeriodicalIF":5.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10763896/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138830206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gut microbiome composition: link between sports performance and protein absorption?","authors":"Péter Fritz, Réka Fritz, Pál Bóday, Ádám Bóday, Emese Bató, Péter Kesserű, Csilla Oláh","doi":"10.1080/15502783.2023.2297992","DOIUrl":"10.1080/15502783.2023.2297992","url":null,"abstract":"<p><strong>Background: </strong>Sufficient protein intake is essential for adequate physical condition and athletic performance. However, numerous factors can influence the absorption of consumed protein, including timing, type of protein intake, and gut microbiota. In the present study, elite male water polo players consumed a plant-based, vegan protein supplement with (<i>n</i> = 10) or without (<i>n</i> = 10) pre- and probiotics daily during the 31-day study period.</p><p><strong>Methods: </strong>We determined the anthropometric characteristics and body composition, dietary habits, gut microbiota composition, and blood parameters of the players at the beginning and at the end of the study. Body composition parameters were analyzed using the InBody 970 bioimpedance analyzer. Gut microbiome composition was determined from stool samples by metagenome sequencing. Paired and unpaired t-tests were used to determine differences between body composition and blood parameters within the groups and between the two groups at the two different sampling times. The Wilcoxon test was used to determine the change in bacterial composition during the study. Correlations between changes in body composition, blood parameters, and taxonomic groups were analyzed using a linear correlation calculation.</p><p><strong>Results: </strong>Skeletal muscle mass (<i>p</i> < 0.001), body cell mass (<i>p</i> = 0.002), arm circumference (<i>p</i> = 0.003), and protein mass (<i>p</i> < 0.001) increased, while body fat mass (<i>p</i> = 0.004) decreased significantly in the intervention group which consumed pre- and probiotics in addition to protein supplement. Activated acetate (reductive TCA cycle I) and propionate (pyruvate fermentation to propanoate I) pathways correlated positively with increased skeletal muscle mass (<i>p</i> < 0.01 and <i>p</i> < 0.05), and the relative abundance of butyrate-producing species showed a significant positive correlation with changes in body fat mass in the intervention group (<i>p</i> < 0.05). These correlations were not observed in the control group without the intake of pre- and probiotics.</p><p><strong>Conclusions: </strong>The composition of the gut microbiota may influence protein absorption and therefore body composition and consequently physical condition and sports performance.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2297992"},"PeriodicalIF":5.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10763846/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139048972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supplementation of L-glutamine enhanced mucosal immunity and improved hormonal status of combat-sport athletes.","authors":"Tung-Lin Lu, Ai-Chi Zheng, Katsuhiko Suzuki, Chi-Cheng Lu, Chung-Yuan Wang, Shih-Hua Fang","doi":"10.1080/15502783.2023.2300259","DOIUrl":"10.1080/15502783.2023.2300259","url":null,"abstract":"<p><strong>Background: </strong>Maintaining proper immune function and hormone status is important for athletes to avoid upper respiratory tract infection (URTI) and insufficient recovery, which is detrimental to sport performance and health. The aim of this study was to evaluate whether three-week supplementation of L-glutamine could benefit the mucosal immunity and hormonal status of combat-sport athletes as well as their rates of upper respiratory tract infection (URTI) and subjective feelings of well-being after intensive training.</p><p><strong>Methods: </strong>Twenty-one combat-sport athletes from the National Taiwan University of Sport were recruited in this study. After intensive training, two groups of the participants were asked to consume powder form of 0.3 g/kg body weight of L-glutamine (GLU group) or maltodextrin (PLA group) with drinking water in a randomized design at the same time every day during 3 weeks. Saliva samples were collected to measure immunoglobulin A (IgA), nitric oxide (NO), testosterone (T) and cortisol (C) before and after three-week supplementation; moreover, Hooper's index questionnaires were completed for wellness assessment. The incidence and duration of URTI were recorded by using a health checklist throughout the entire study period.</p><p><strong>Results: </strong>Supplementation of L-glutamine significantly enhanced the concentrations of IgA and NO in saliva; additionally, the incidence of URTI was significantly reduced. Regarding hormones, T concentration was significantly decreased in the PLA group, whereas C concentration was significantly increased, resulting in a significant decrease of T/C ratio. In contrast, the GLU group showed a significant increase of T/C ratio, while the mood scores of the Hooper's index questionnaire were higher in the PLA group.</p><p><strong>Conclusions: </strong>Three-week supplementation of L-glutamine after intensive training enhanced the mucosal immunity, improved hormonal status and reduced the rate of URTI of combat-sport athletes while feelings of well-being were also enhanced. Therefore, L-glutamine would be beneficial for the sports performance and recovery of athletes.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2300259"},"PeriodicalIF":5.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783826/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139403337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy intake, hydration status, and sleep of world-class male archers during competition.","authors":"Ozcan Esen, Ian Walshe, Stuart Goodall","doi":"10.1080/15502783.2024.2345358","DOIUrl":"10.1080/15502783.2024.2345358","url":null,"abstract":"<p><strong>Background: </strong>Nutritional intake and sleep, play an important role for recovery and performance in elite sport but little work has been undertaken in archery. The present study aimed to assess energy intake (EI), hydration status, and sleep parameters in world-class male archers over the course of a four-day competition.</p><p><strong>Methods: </strong>Results, Conclusions Six male, elite-standard archers participated in the study and measurements of hydration status, EI, competition load, and sleep were recorded throughout each day of competition.</p><p><strong>Results: </strong>Daily energy, carbohydrate, and protein intake ranged between 2,563 and 3,986 kcal, 4 and 7.1 g/kg BM, 2.2 and 3.6 g/kg BM per day, respectively. Thus, archers practiced elements of periodized nutrition such that energy and carbohydrate intake was greater on the high-volume competition days (i.e. days 1 and 3; more numbers of arrows, longer duration, and walking distance) in comparison to low-volume days (days 2 and 4) over the tournament (all <i>p</i> > 0.01). Additionally, urine specific gravity was higher after waking, compared to pre- and post-competition, and before bed (all <i>p</i> < 0.05). This indicates that archers were euhydrated pre- and post-competition and before bedtime, while they were slightly hypohydrated after waking up. Sleep data show that disturbances were kept to a minimum.</p><p><strong>Conclusions: </strong>Collectively, archers appear capable of periodizing their nutritional intake according to daily physical loading during a tournament whilst, staying euhydrated and maintaining sleep quality. In part, such data can help to explain why these archers experience a sustained level of success.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2345358"},"PeriodicalIF":5.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11075653/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140859210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Agreement between fat-free mass from bioelectrical impedance analysis and dual-energy X-ray absorptiometry and their use in estimating resting metabolic rate in resistance-trained men.","authors":"Alex S Ribeiro, Sandro L Sofiati, Witalo Kassiano, Diogo V Martinho, Matheus A Nascimento, Ademar Avelar, Michele C C Trindade, Jerry L Mayhew, Edilson S Cyrino","doi":"10.1080/15502783.2024.2357319","DOIUrl":"10.1080/15502783.2024.2357319","url":null,"abstract":"<p><strong>Background: </strong>This study aimed to determine the agreement between fat-free mass (FFM) estimates from bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) and their use in estimating resting metabolic rate (RMR) in men undergoing resistance training.</p><p><strong>Methods: </strong>Thirty healthy resistance-trained men (22.7 ± 4.4 years, 70.0 ± 8.7 kg, 174.6 ± 6.7 cm, and 22.9 ± 2.3 kg/m²) were evaluated. The equation developed by Tinsley et al. (RMR = 25.9 × fat-free mass [FFM] + 284) was adopted to calculate the RMR. DXA was used as the reference method for FFM.</p><p><strong>Results: </strong>Furthermore, FFM was also estimated by BIA using a spectral device. No significant difference (<i>p</i> > 0.05) was observed between DXA (1884.2 ± 145.5 kcal) and BIA (1849.4 ± 167.7 kcal) to estimate RMR. A positive and significant correlation (<i>r</i> = 0.89, <i>p</i> < 0.05) was observed between DXA and BIA estimates of RMR. The mean difference between methods indicated that BIA presented a bias of -34.8 kcal.</p><p><strong>Conclusion: </strong>These findings suggest that using FFM derived from DXA or BIA results in similar RMR estimates in resistance-trained men.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2357319"},"PeriodicalIF":4.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11216238/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141469042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarization.","authors":"Nathaniel J Helwig, Laura E Schwager, Alexander C Berry, Anna C Zucker, Jacob S Venenga, Samantha C Sterbenz, Nathaniel D M Jenkins","doi":"10.1080/15502783.2024.2379424","DOIUrl":"10.1080/15502783.2024.2379424","url":null,"abstract":"<p><strong>Purpose: </strong>We conducted a randomized, double-blind, placebo-controlled crossover trial in young adults to examine the dose-dependent (600 mg versus 1200 mg), acute effects of consumption of an <i>Ilex guayusa</i> tea extract (GLE) on mood, cognitive and motor-cognitive performance, as well as its acute cardiovascular effects.</p><p><strong>Methods: </strong>Twenty-five adults (mean ± SD, age = 28 ± 7 y; 9 M/16 F) completed familiarization and then three randomly ordered experimental visits where they consumed either 600 mg (GLE₆₀₀) or 1200 mg (GLE₁₂₀₀) GLE or placebo (PLA). Following supplement consumption, participants completed a mood state survey, assessments of perceived jitteriness, energy, and focus, and neurocognitive and motor-cognitive testing. Blood pressure (BP), heart rate, and QT interval length were determined before and after supplementation.</p><p><strong>Results: </strong>GLE₆₀₀ significantly improved total mood disturbance (mean ± SE difference = -6.9 ± 2.6 au, <i>p</i> = 0.034), fatigue-inertia (-2.84 ± 0.89 au, <i>p</i> = 0.008), perceived energy (+13.00 ± 4.49 au; <i>p</i> = 0.02), motor speed (+4.52 ± 1.42 au, <i>p</i> = 0.008), and psychomotor speed (+7.20 ± 2.16 au, <i>p</i> = 0.005) relative to PLA. GLE₁₂₀₀ also improved psychomotor speed (+5.08 ± 2.16 ms, <i>p</i> = 0.045) and uniquely increased motor-cognitive performance as reflected by a decrease in reaction time (-0.106 ± 0.04 ms, <i>p</i> = 0.026) during a neurocognitive hop test. The effect of GLE on jitteriness was both dose- and sex-dependent. Jitteriness increased with increasing GLE dose in women only (<i>p</i> < 0.001). Both GLE₆₀₀ and GLE₁₂₀₀ similarly increased systolic and diastolic BP by 4-5 mmHg (<i>p</i> ≤ 0.022). Neither GLE₆₀₀ nor GLE₁₂₀₀ acutely influenced QTc length (<i>p</i> = 0.31).</p><p><strong>Conclusions: </strong>The goal of GLE supplementation should be considered when selecting a dosing strategy. Lower dosages of GLE (e.g. 600 mg) appear to optimize cognitive and mood-related outcomes while limiting side-effects such as jitteriness in women, and higher dosages may be necessary (e.g. 1200 mg) to promote improvements in motor-cognitive performance.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2379424"},"PeriodicalIF":4.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11257001/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141627085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of coffee intake on skeletal muscle microvascular reactivity at rest and oxygen extraction during exercise: a randomized cross-over trial.","authors":"Bin Leng, Haizhen Huang, Chuan Zhang","doi":"10.1080/15502783.2024.2409673","DOIUrl":"10.1080/15502783.2024.2409673","url":null,"abstract":"<p><strong>Purpose: </strong>The effects of coffee ingestion on skeletal muscle microvascular function are not well understood. This study aimed to investigate the acute effects of coffee intake with varying levels of caffeine on skeletal muscle microvascular reactivity at rest and oxygen extraction during maximal incremental exercise in physically active individuals.</p><p><strong>Methods: </strong>Twenty healthy young male participants were administered coffee with low caffeine (3 mg/kg body weight; LC), high caffeine (6 mg/kg body weight; HC), and placebo (decaf) in different sessions. Skeletal muscle reactivity indexes, including tissue saturation index 10s slope (TSI10) and TSI half time recovery (TSI ½) following 5-minute ischemia were measured at rest and were measured at baseline and post-coffee consumption using near-infrared spectroscopy (NIRS). Post-coffee intake, NIRS was also used to measure microvascular oxygen extraction during exercise via maximal incremental exercise. Peak oxygen consumption and peak power output (W_peak) were simultaneously evaluated.</p><p><strong>Results: </strong>Post-coffee consumption, TSI10 was significantly higher in the LC condition compared to placebo (<i>p</i> = 0.001) and significantly higher in the HC condition compared to placebo (<i>p</i> < 0.001). However, no difference was detected between LC and HC conditions (<i>p</i> = 0.527). HC condition also showed significant less TSI ½ compared to placebo (<i>p</i> = 0.005). However, no difference was detected for microvascular oxygen extraction during exercise, despite the greater W_peak found for HC condition (<i>p</i> < 0.001) compared to placebo.</p><p><strong>Conclusion: </strong>Coffee ingestion with high caffeine level (6 mg/kg body weight) significantly enhanced skeletal muscle reactivity at rest. However, the improvement of exercise performance with coffee intake is not accompanied by alterations in muscle oxygen extraction.</p>","PeriodicalId":17400,"journal":{"name":"Journal of the International Society of Sports Nutrition","volume":"21 1","pages":"2409673"},"PeriodicalIF":4.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11445882/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}