This study investigated the effects of acute sodium bicarbonate (SB) supplementation co-ingested with a carbohydrate-rich meal on 10-km running performance and gastrointestinal symptoms in recreational female runners under field-based conditions. Twenty-one healthy women (33.6 ± 4.6 years; body mass index 20.8 ± 1.3 kg/m; maximal oxygen uptake 48.6 ± 2.0 ml·kg −1 ·min −1 ) completed two 10-km outdoor track running time trials (TTs) in a randomized, double-blind, crossover design. Participants ingested either SB (0.3 g/kg body mass [BM]) or placebo (PLA; 0.03 g/kg BM table salt), together with a standardized carbohydrate-rich meal (1.5 g/kg BM), 90 min before exercise during the same phase of the menstrual cycle. Blood pH, bicarbonate [HCO 3 − ], and [lactate] were measured before, and 1, 3, 5, and 7 min after the TTs; performance time was recorded. Gastrointestinal symptoms were recorded at 30, 60, and 90 min after SB and PLA ingestions. Blood pH (7.47 ± 0.03 vs. 7.42 ± 0.04, p < .001) and [HCO 3 − ] (27.7 ± 1.4 vs. 22.2 ± 1.5 mmol/L, p < .001) were higher at rest and remained elevated postexercise following SB compared with PLA ( p < .05 for all time points). TT completion time improved after SB compared with PLA (3,046.1 ± 208.7 s vs. 3,078.4 ± 206.8 s; p = .011). No significant differences in gastrointestinal symptoms scores were observed between conditions ( p > .05 for all). In conclusion, acute co-ingestion of 0.3 g/kg of SB with a carbohydrate-rich meal is a practical and well-tolerated strategy to achieve higher resting blood [HCO 3 − ] and pH as well as to improve 10-km TT running performance in recreational female runners.
Objectives: This study aims to systematically evaluate the effects of acute and chronic L-carnitine supplementation on endurance performance and substrate oxidation during exercise among active individuals. Methods: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. A total of 647 studies were initially EBSCO Academic Search Ultimate, and SPORTDiscus databases, with searches conducted from database inception to February 1, 2026. Randomized placebo-controlled crossover and parallel-group trials were eligible for inclusion. Studies meeting the inclusion criteria were assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, with the crossover-specific version applied to randomized crossover trials. Results: A total of 18 studies met the inclusion criteria. Overall, 15 (83%) studies were rated as having some concerns, three (17%) were classified as having a high risk of bias, and none were judged to be at low risk of bias. Ten studies investigated acute L-carnitine supplementation (2-15 g), seven studies examined chronic supplementation (2-3 g/day for 2-24 weeks), and one study evaluated both acute and chronic supplementation (3 g on a single day and over 2 weeks). Both acute and chronic L-carnitine supplementation were associated with improvements in endurance performance following acute supplementation and chronic supplementation. By contrast, no significant changes in fat oxidation during exercise were reported after either acute (2-4 g ingested 120-180 min before exercise) or chronic supplementation (2 g/day for 2-4 weeks). Conclusions: L-carnitine may enhance selected endurance performance outcomes among active individuals; however, its reputation as a "fat-burning" ergogenic aid is not supported by current evidence, following short-term supplementation.
This article provides a synopsis of the 10 Questions/10 Experts session at the 2026 American College of Sports Medicine Annual Meeting, which examined whether sports nutrition guidelines are equally applicable from recreational to elite athletes. Each speaker considered the validity of a given common "myth" statement and provided an evidence-based opinion to support, bust, or qualify propositions addressing the following questions: (a) Are sports nutrition guidelines based primarily on studies of elite athletes, and are they too serious for recreational athletes? (b) Do recreational marathon runners need the same in-race carbohydrate recommendations as elite marathon runners? (c) Must recreational athletes consume 1.6 g & centerdot;kg-1 & centerdot;day-1 of protein to benefit from exercise training? (d) Does nitrate supplementation benefit elite and recreational athletes equally? (e) Do recreational athletes need a structured fluid intake plan? (f) Is sodium bicarbonate loading relevant only to elite athletes? (g) Do recreational and elite athletes require more micronutrients than suggested by the Recommended Dietary Allowances? (h) Is eating after 8:00 p.m. detrimental to performance or recovery in recreational athletes? (i) Are recreational athletes at greater risk for suboptimal vitamin D status because indoor occupations reduce sunlight exposure? and (j) Should recreational athletes train with low carbohydrate availability to amplify adaptation? This article describes the content of each presentation, including the most important evidence, practical implications, and conclusions identified by the presenters.
Purpose: We investigated whether a small dose of alcoholic beer ingested before a running exercise bout impaired performance and changed psychophysiological responses to exercise. Methods: After three sessions of familiarizations, 16 healthy and physically active men (25.8 +/- 5.1 years, 175.0 +/- 5.4 cm, and 76 +/- 6.5 kg) performed a 30-min running time trial in a double-blind and placebocontrolled crossover design, after ingesting either beer (alcohol 4.8% v/v; 0.3 g/kg) or nonalcoholic beer (placebo). Performance, cardiopulmonary (oxygen consumption, ventilation, respiratory exchange ratio, and heart rate), and perceptual (perceived exertion, affect, and motivation) variables were assessed throughout the trial and averaged every 5 min during exercise. Running economy was assessed during steady-state running at 8 km/hr. The data were analyzed through t tests and repeated-measures mixed models (p < .05). Results: The ingestion of beer significantly decreased the average speed by 4.7% (p = .04; d = 0.21) and total distance covered by 4.3% (p = .007; d= 0.26) when compared with placebo. The ingestion of beer also impaired the running economy by 1.1% (p = .01; d = 0.39) and increased respiratory exchange ratio throughout the exercise bout (p = .004, d =1.07). No beer-by-time interaction effects were detected in cardiopulmonary outcomes (p>.05). Conclusions: A small dose of alcoholic beer reduced the exercise capacity of healthy individuals, likely due to an impairment in running economy.
This study aimed to determine the accuracy of a multiinput wearable device (Actiheart 5) and commercially available accelerometer (GENEActiv) in the estimation of exercise energy expenditure (EEE) during intermittent high-intensity and resistance exercise sessions among 31 trained females. Data were collected over two testing sessions involving (a) measurement of resting metabolic rate, physique and a graded exercise test on a treadmill to enable individualized calibration of the wearables, and (b) A modified Bath University Rugby Union Shuttle Test followed by a resistance exercise session. GENEActiv and Actiheart EEE-derived measures, using both generic and individually calibrated algorithms, were compared against (a) indirect calorimetry for Bath University Rugby Union Shuttle Test and (b) indirect calorimetry plus the estimated anaerobic energy contribution based on blood lactate responses for resistance exercise. Equivalence was evaluated using predefined bounds of +/- 10% mean indirect calorimetry EEE. The use of individually-calibrated Actiheart algorithms improved estimation of EEE during Bath University Rugby Union Shuttle Test (mean bias 4.5 +/- 60.4 kcal) compared with individually-calibrated GENEActiv algorithms (mean bias 69.5 +/- 86.6 kcal), and equivalence with indirect calorimetry was achieved, although substantial individual error remained (95% limits of agreement -113.9 to 122.8 kcal and intraclass correlation coefficients, .62 [.34 to .80]). Individualized Actiheart algorithms provided equivalent group-level estimates of EEE during intermittent high-intensity exercise, whereas neither Actiheart nor GENEActiv demonstrated acceptable validity or equivalence against the reference method for resistance training, suggesting Metabolic Equivalents of Task may be a more practical method of estimating EEE.
