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Frisaldi E, Shaibani A, Benedetti F, Pagnini F. Placebo and nocebo effects and mechanisms associated with pharmacological interventions: an umbrella review. BMJ Open 2023; 13:e077243. [PMID: 37848293 PMCID: PMC10582987 DOI: 10.1136/bmjopen-2023-077243] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/27/2023] [Indexed: 10/19/2023] Open
Abstract
OBJECTIVES This review aimed to summarise the existing knowledge about placebo and nocebo effects associated with pharmacological interventions and their mechanisms. DESIGN Umbrella review, adopting the Assessment of Multiple Systematic Reviews 2 tool for critical appraisal. DATA SOURCES MEDLINE/PubMed, Scopus, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trial were searched in September 2022, without any time restriction, for systematic reviews, narrative reviews, original articles. Results were summarised through narrative synthesis, tables, 95% CI. OUTCOME MEASURES Mechanisms underlying placebo/nocebo effects and/or their effect sizes. RESULTS The databases search identified 372 studies, for a total of 158 312 participants, comprising 41 systematic reviews, 312 narrative reviews and 19 original articles. Seventy-three per cent of the examined systematic reviews were of high quality.Our findings revealed that mechanisms underlying placebo and/or nocebo effects have been characterised, at least in part, for: pain, non-noxious somatic sensation, Parkinson's disease, migraine, sleep disorders, intellectual disability, depression, anxiety, dementia, addiction, gynaecological disorders, attention-deficit hyperactivity disorder, immune and endocrine systems, cardiovascular and respiratory systems, gastrointestinal disorders, skin diseases, influenza and related vaccines, oncology, obesity, physical and cognitive performance. Their magnitude ranged from 0.08 to 2.01 (95% CI 0.37 to 0.89) for placebo effects and from 0.32 to 0.90 (95% CI 0.24 to 1.00) for nocebo effects. CONCLUSIONS This study provides a valuable tool for clinicians and researchers, identifying both results ready for clinical practice and gaps to address in the near future. FUNDING Università Cattolica del Sacro Cuore, Milan, Italy with the 'Finanziamento Ponte 2022' grant. PROSPERO REGISTRATION NUMBER CRD42023392281.
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Affiliation(s)
- Elisa Frisaldi
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - Aziz Shaibani
- Muscle and Nerve Center, Houston, Texas, USA
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Fabrizio Benedetti
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - Francesco Pagnini
- Department of Psychology, Università Cattolica del Sacro Cuore, Milan, Italy
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Nabuco LL, Mendes GF, Barreto G, Saunders B, Reis CEG. Spit It Out: Is Caffeine Mouth Rinse an Effective Ergogenic Aid? A Systematic Review and Meta-Analysis. Strength Cond J 2023. [DOI: 10.1519/ssc.0000000000000777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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Berjisian E, Naderi A, Mojtahedi S, Grgic J, Ghahramani MH, Karayigit R, Forbes JL, Amaro-Gahete FJ, Forbes SC. Are Caffeine's Effects on Resistance Exercise and Jumping Performance Moderated by Training Status? Nutrients 2022; 14:nu14224840. [PMID: 36432526 PMCID: PMC9692585 DOI: 10.3390/nu14224840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/10/2022] [Accepted: 11/13/2022] [Indexed: 11/17/2022] Open
Abstract
This study aimed to explore if the effects of caffeine intake on resistance exercise and jumping performance are moderated by training status. We included ten resistance-trained and ten recreationally active males in a randomized, double-blind, crossover study. Participants were categorized into groups according to their resistance to training experience and muscular strength levels. Exercise performance outcomes included weight lifted and mean velocity during a one-repetition maximum (1RM) bench press and squat; repetitions were performed to muscular failure in the same exercises with 70% of 1RM and countermovement jump (CMJ) height. Exercise performance was evaluated on three occasions, following no substance ingestion (control), caffeine (6 mg/kg), and placebo. There was a main effect on the condition for all the performance outcomes (all p ≤ 0.02), except for the 1RM squat mean velocity (p = 0.157) and 1RM bench press mean velocity (p = 0.719). For weight lifted in the 1RM bench press, there was a significant difference when comparing the caffeine vs. control, caffeine vs. placebo, and placebo vs. control. For weight lifted in the 1RM squat, a significant difference was found when comparing the caffeine vs. control. For muscular endurance outcomes and jump height, a significant difference was found when caffeine was compared to the control or placebo. Effect sizes were trivial for muscular strength (Hedges' g: 0.04-0.12), small for the jump height (Hedges' g: 0.43-0.46), and large for muscular endurance (Hedges' g: 0.89-1.41). Despite these ergogenic effects, there was no significant training status × caffeine interaction in any of the analyzed outcomes. In summary, caffeine ingestion is ergogenic for muscular strength, endurance, and jump height. These effects are likely to be of a similar magnitude in resistance-trained and recreationally active men.
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Affiliation(s)
- Erfan Berjisian
- Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Tehran University, Tehran 1417935840, Iran
| | - Alireza Naderi
- Department of Exercise Physiology, Borujerd Branch, Islamic Azad University, Borujerd 6915136111, Iran
| | - Shima Mojtahedi
- Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Tehran University, Tehran 1417935840, Iran
- Correspondence: (S.M.); (S.C.F.)
| | - Jozo Grgic
- Institute for Health and Sport, Victoria University, Melbourne, VIC 3011, Australia
| | - Mohammad Hossein Ghahramani
- Physical Education and Sport Sciences Department, Faculty of Humanities, Tarbiat Modares University, Tehran 1411713116, Iran
| | - Raci Karayigit
- Faculty of Sport Sciences, Ankara University, Gölbaşı, Ankara 06830, Turkey
| | - Jennifer L. Forbes
- Department of Physical Education Studies, Brandon University, Brandon, MB R7A 6A9, Canada
| | - Francisco J. Amaro-Gahete
- PROmoting FITness and Health through Physical Activity Research Group (PROFITH), Department of Physical and Sports Education, Faculty of Sports Science, University of Granada, 18011 Granada, Spain
- Department of Physiology, Faculty of Medicine, EFFECTS-262 Research Group, University of Granada, 18016 Granada, Spain
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Scott C. Forbes
- Department of Physical Education Studies, Brandon University, Brandon, MB R7A 6A9, Canada
- Correspondence: (S.M.); (S.C.F.)
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Grgic J, Venier S, Mikulic P. Examining the Effects of Caffeine on Isokinetic Strength, Power, and Endurance. J Funct Morphol Kinesiol 2022; 7:jfmk7040071. [PMID: 36278732 PMCID: PMC9590023 DOI: 10.3390/jfmk7040071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/13/2022] [Accepted: 09/18/2022] [Indexed: 11/16/2022] Open
Abstract
This study examined caffeine's effects on isokinetic strength, power, and endurance. The sample included 25 young, resistance-trained males. The participants were tested on three occasions, in a control trial (no substance ingestion) and following the ingestion of 6 mg·kg-1 of caffeine or placebo. Exercise tests involved isokinetic knee extension and flexion using angular velocities of 60° s-1 and 180° s-1. Analyzed outcomes included peak torque, average power, and total work. For knee extension at an angular velocity of 60° s-1, there were significant differences for: (1) peak torque when comparing caffeine vs. control (Hedges' g = 0.22) and caffeine vs. placebo (g = 0.30) and (2) average power when comparing caffeine vs. control (g = 0.21) and caffeine vs. placebo (g = 0.29). For knee extension at an angular velocity of 180° s-1, there were significant differences for: (1) peak torque when comparing caffeine vs. placebo (g = 0.26), (2) average power when comparing caffeine vs. control (g = 0.36) and caffeine vs. placebo (g = 0.43), and (3) total work when comparing caffeine vs. control (g = 0.33) and caffeine vs. placebo (g = 0.36). Caffeine was not ergogenic for knee flexors in any of the analyzed outcomes. Additionally, there was no significant difference between control and placebo. In summary, caffeine enhances the mechanical output of the knee extensors at lower and higher angular velocities, and these effects are present when compared to placebo ingestion or no substance ingestion (control).
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Affiliation(s)
- Jozo Grgic
- Institute for Health and Sport, Victoria University, Melbourne, VIC 3011, Australia
- Correspondence:
| | - Sandro Venier
- Faculty of Kinesiology, University of Zagreb, 10000 Zagreb, Croatia
| | - Pavle Mikulic
- Faculty of Kinesiology, University of Zagreb, 10000 Zagreb, Croatia
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Painelli VDS, Brietzke C, Franco-Alvarenga PE, Canestri R, Vinícius Í, Pires FO. A Narrative Review of Current Concerns and Future Perspectives of the Carbohydrate Mouth Rinse Effects on Exercise Performance. SAGE Open Med 2022; 10:20503121221098120. [PMID: 35615525 PMCID: PMC9125602 DOI: 10.1177/20503121221098120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/13/2022] [Indexed: 11/16/2022] Open
Abstract
Previous systematic reviews have confirmed that carbohydrate (CHO) mouth rinse
may boost physical exercise performance, despite some methodological aspects
likely affecting its ergogenic effect. In this review, we discussed if the
exercise mode, pre-exercise fasting status, CHO solutions concentration, CHO
solutions temperature, mouth rinse duration, and CHO placebo effects may
potentially reduce the CHO mouth rinse ergogenic effect, suggesting possible
solutions to manage these potential confounders. The effectiveness of CHO mouth
rinse as a performance booster is apparently related to the origin of the
exercise-induced neuromuscular fatigue, as CHO mouth rinse unequivocally
potentiates endurance rather than sprint and strength exercises performance.
Furthermore, ergogenic effects have been greater in fasting than fed state,
somehow explaining the varied magnitude of the CHO mouth rinse effects in
exercise performance. In this regard, the CHO solution concentration and
temperature, as well as the mouth rinse duration, may have increased the
variability observed in CHO mouth rinse effects in fasting and fed state.
Finally, placebo effects have challenged the potential of the CHO mouth rinse as
an ergogenic aid. Therefore, we suggest that future studies should consider
methodological controls such as sample size and sample homogeneity, proper
familiarization with experimental procedures, and the use of alternative placebo
designs to provide unbiased evidence regarding the potential of the CHO mouth
rinse as an ergogenic aid.
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Affiliation(s)
- Vitor de Salles Painelli
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
- Strength Training Study and Research Group, Institute of Health Sciences, Paulista University, São Paulo, Brazil
| | - Cayque Brietzke
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
- Human Movement Science and Rehabilitation Program, Federal University of São Paulo, Santos, Brazil
| | - Paulo Estevão Franco-Alvarenga
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
- Human Movement Science and Rehabilitation Program, Federal University of São Paulo, Santos, Brazil
| | - Raul Canestri
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Ítalo Vinícius
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Flávio Oliveira Pires
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
- Human Movement Science and Rehabilitation Program, Federal University of São Paulo, Santos, Brazil
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Barreto G, Loureiro LMR, Reis CEG, Saunders B. Effects of caffeine chewing gum supplementation on exercise performance: a systematic review and meta-analysis. Eur J Sport Sci 2022; 23:714-725. [PMID: 35239468 DOI: 10.1080/17461391.2022.2049885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The aim of this systematic review with meta-analysis was to determine the effect of caffeine gum (Caff-gum) on exercise performance-related outcomes. Medline, EmBase, and SPORTSDiscus, and the register ClinicalTrials.gov were searched in March 2021, for studies assessing the effect of Caff-gum in placebo-controlled protocols involving healthy adults (i.e., with no chronic diseases or health conditions). Risk of bias was assessed using the RoB 2 tool. Random-effects meta-analyses using standardized mean differences (SMD) were performed to determine the effect of Caff-gum on exercise outcomes with several sub-analyses (training status, exercise type, timing and dose) for potential modifying factors. 14 studies were included, totaling 200 participants. There was a significant overall effect of Caff-gum compared to placebo (SMD = 0.21, 95%CI: 0.10-0.32; p = 0.001). Subgroup analysis showed improved performance for trained (SMD = 0.23, 95%CI: 0.08-0.37; p = 0.004), but not for untrained (SMD = 0.14, 95%CI: -0.02-0.29; p = 0.07) individuals. Caff-gum improved both endurance (SMD = 0.27, 95%CI: 0.12-0.42; p = 0.002) and strength/power (SMD = 0.20, 95%CI: 0.03-0.37; p = 0.03) performance outcomes. Caff-gum was ergogenic when consumed within 15 min prior to initiating exercise (SMD = 0.27, 95%CI: 0.07-0.4; p = 0.01), but not when provided >15 min prior (SMD=-0.48, 95%CI= -1.7-0.82; p = 0.25). There was no significant effect of Caff-gum with doses <3 mg/kg body mass (BM) (SMD = 0.20, 95%CI: -0.03-0.43; p = 0.07), but there was a significant effect when the dose was ≥3 mg/kg BM (SMD = 0.22, 95%CI: 0.07-0.37; p = 0.01). Caff-gum supplementation may be an effective ergogenic strategy for trained athletes involved in both endurance and strength/power exercise, using a recommended dose of ≥3 mg/kg BM consumed within 15 minutes before the exercise.
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Affiliation(s)
- G Barreto
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport; Rheumatology Division; Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, SP, BR, University of São Paulo, SP, Brazil
| | - L M R Loureiro
- Faculty of Nutrition FANUT, Department of Food and Nutrition, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - C E G Reis
- Department of Nutrition, Universidade de Brasília, Brasília, DF, Brazil
| | - B Saunders
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, Brazil
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de Oliveira LF, Dolan E, Swinton PA, Durkalec-Michalski K, Artioli GG, McNaughton LR, Saunders B. Extracellular Buffering Supplements to Improve Exercise Capacity and Performance: A Comprehensive Systematic Review and Meta-analysis. Sports Med 2022; 52:505-526. [PMID: 34687438 DOI: 10.1007/s40279-021-01575-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Extracellular buffering supplements [sodium bicarbonate (SB), sodium citrate (SC), sodium/calcium lactate (SL/CL)] are ergogenic supplements, although questions remain about factors which may modify their effect. OBJECTIVE To quantify the main effect of extracellular buffering agents on exercise outcomes, and to investigate the influence of potential moderators on this effect using a systematic review and meta-analytic approach. METHODS This study was designed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Three databases were searched for articles that were screened according to inclusion/exclusion criteria. Bayesian hierarchical meta-analysis and meta-regression models were used to investigate pooled effects of supplementation and moderating effects of a range of factors on exercise and biomarker responses. RESULTS 189 articles with 2019 participants were included, 158 involving SB supplementation, 30 with SC, and seven with CL/SL; four studies provided a combination of buffering supplements together. Supplementation led to a mean estimated increase in blood bicarbonate of + 5.2 mmol L-1 (95% credible interval (CrI) 4.7-5.7). The meta-analysis models identified a positive overall effect of supplementation on exercise capacity and performance compared to placebo [ES0.5 = 0.17 (95% CrI 0.12-0.21)] with potential moderating effects of exercise type and duration, training status and when the exercise test was performed following prior exercise. The greatest ergogenic effects were shown for exercise durations of 0.5-10 min [ES0.5 = 0.18 (0.13-0.24)] and > 10 min [ES0.5 = 0.22 (0.10-0.33)]. Evidence of greater effects on exercise were obtained when blood bicarbonate increases were medium (4-6 mmol L-1) and large (> 6 mmol L-1) compared with small (≤ 4 mmol L-1) [βSmall:Medium = 0.16 (95% CrI 0.02-0.32), βSmall:Large = 0.13 (95% CrI - 0.03 to 0.29)]. SB (192 outcomes) was more effective for performance compared to SC (39 outcomes) [βSC:SB = 0.10 (95% CrI - 0.02 to 0.22)]. CONCLUSIONS Extracellular buffering supplements generate large increases in blood bicarbonate concentration leading to positive overall effects on exercise, with sodium bicarbonate being most effective. Evidence for several group-level moderating factors were identified. These data can guide an athlete's decision as to whether supplementation with buffering agents might be beneficial for their specific aims.
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Affiliation(s)
- Luana Farias de Oliveira
- Applied Physiology & Nutrition Research Group, Rheumatology Division, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil
| | - Eimear Dolan
- Applied Physiology & Nutrition Research Group, Rheumatology Division, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil
| | - Paul A Swinton
- School of Health Sciences, Robert Gordon University, Aberdeen, UK
| | - Krzysztof Durkalec-Michalski
- Department of Sports Dietetics, Poznań University of Physical Education, Poznań, Poland
- Department of Human Nutrition and Dietetics, Poznań University of Life Sciences, Poznań, Poland
| | - Guilherme G Artioli
- Department of Life Sciences, Manchester Metropolitan University, John Dalton Building, Manchester, M1 5GD, UK
| | - Lars R McNaughton
- Sports Nutrition and Performance Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, UK
| | - Bryan Saunders
- Applied Physiology & Nutrition Research Group, Rheumatology Division, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil.
- Department of Sports Dietetics, Poznań University of Physical Education, Poznań, Poland.
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil.
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Carbohydrate Mouth Rinse Increases High but Not Low Intensity Repetitions to Failure in Resistance-Trained Males. Nutrients 2022; 14:nu14040875. [PMID: 35215525 PMCID: PMC8875644 DOI: 10.3390/nu14040875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023] Open
Abstract
Carbohydrate mouth rinsing (CMR) has been shown to enhance exercise performance. However, the influence of CMR on repetitions to failure with different intensities (40% or 80% of 1 RM) is unknown. Therefore, the purpose of this study was to examine the effects of a 6% CMR solution on muscular endurance assessed at 40% and 80% of 1 RM in resistance-trained males. Sixteen resistance-trained males (age: 25 ± 3 years, height: 182 ± 6 cm, body mass: 86 ± 3 kg, body fat: 16 ± 3%, bench press 1 RM: 106 ± 16 kg, resistance training experience: 5 ± 1 years) completed four conditions in random order. The four conditions consisted of ten seconds of mouth rinsing with 25 mL solutions containing either maltodextrin or placebo (sweetened water) prior to performing a bench press muscular endurance test at either 40% of 1 RM or 80% of 1 RM. Total repetitions, heart rate (HR), ratings of perceived exertion (RPE), glucose (GLU) and felt arousal (FA) were recorded for each condition. There was a significant condition by intensity interaction (p = 0.02). CMR significantly increased total repetitions compared with placebo at the higher intensity (80% of 1 RM; p = 0.04), while there was no effect at the lower intensity (p = 0.20). In addition, HR, RPE, GLU and FA did not differ between conditions or across intensities (p > 0.05). In conclusion, CMR-enhanced muscular endurance performed at higher but not lower intensities.
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Grgic J, Pedisic Z, Saunders B, Artioli GG, Schoenfeld BJ, McKenna MJ, Bishop DJ, Kreider RB, Stout JR, Kalman DS, Arent SM, VanDusseldorp TA, Lopez HL, Ziegenfuss TN, Burke LM, Antonio J, Campbell BI. International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. J Int Soc Sports Nutr 2021; 18:61. [PMID: 34503527 PMCID: PMC8427947 DOI: 10.1186/s12970-021-00458-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 02/07/2023] Open
Abstract
Based on a comprehensive review and critical analysis of the literature regarding the effects of sodium bicarbonate supplementation on exercise performance, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Supplementation with sodium bicarbonate (doses from 0.2 to 0.5 g/kg) improves performance in muscular endurance activities, various combat sports, including boxing, judo, karate, taekwondo, and wrestling, and in high-intensity cycling, running, swimming, and rowing. The ergogenic effects of sodium bicarbonate are mostly established for exercise tasks of high-intensity that last between 30 s and 12 min. 2. Sodium bicarbonate improves performance in single- and multiple-bout exercise. 3. Sodium bicarbonate improves exercise performance in both men and women. 4. For single-dose supplementation protocols, 0.2 g/kg of sodium bicarbonate seems to be the minimum dose required to experience improvements in exercise performance. The optimal dose of sodium bicarbonate dose for ergogenic effects seems to be 0.3 g/kg. Higher doses (e.g., 0.4 or 0.5 g/kg) may not be required in single-dose supplementation protocols, because they do not provide additional benefits (compared with 0.3 g/kg) and are associated with a higher incidence and severity of adverse side-effects. 5. For single-dose supplementation protocols, the recommended timing of sodium bicarbonate ingestion is between 60 and 180 min before exercise or competition. 6. Multiple-day protocols of sodium bicarbonate supplementation can be effective in improving exercise performance. The duration of these protocols is generally between 3 and 7 days before the exercise test, and a total sodium bicarbonate dose of 0.4 or 0.5 g/kg per day produces ergogenic effects. The total daily dose is commonly divided into smaller doses, ingested at multiple points throughout the day (e.g., 0.1 to 0.2 g/kg of sodium bicarbonate consumed at breakfast, lunch, and dinner). The benefit of multiple-day protocols is that they could help reduce the risk of sodium bicarbonate-induced side-effects on the day of competition. 7. Long-term use of sodium bicarbonate (e.g., before every exercise training session) may enhance training adaptations, such as increased time to fatigue and power output. 8. The most common side-effects of sodium bicarbonate supplementation are bloating, nausea, vomiting, and abdominal pain. The incidence and severity of side-effects vary between and within individuals, but it is generally low. Nonetheless, these side-effects following sodium bicarbonate supplementation may negatively impact exercise performance. Ingesting sodium bicarbonate (i) in smaller doses (e.g., 0.2 g/kg or 0.3 g/kg), (ii) around 180 min before exercise or adjusting the timing according to individual responses to side-effects, (iii) alongside a high-carbohydrate meal, and (iv) in enteric-coated capsules are possible strategies to minimize the likelihood and severity of these side-effects. 9. Combining sodium bicarbonate with creatine or beta-alanine may produce additive effects on exercise performance. It is unclear whether combining sodium bicarbonate with caffeine or nitrates produces additive benefits. 10. Sodium bicarbonate improves exercise performance primarily due to a range of its physiological effects. Still, a portion of the ergogenic effect of sodium bicarbonate seems to be placebo-driven.
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Affiliation(s)
- Jozo Grgic
- Institute for Health and Sport, Victoria University, Melbourne, Australia.
| | - Zeljko Pedisic
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Bryan Saunders
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport; Rheumatology Division; Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, BR, University of São Paulo, Sao Paulo, Brazil
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, Sao Paulo, Brazil
| | - Guilherme G Artioli
- Centre for Bioscience, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | | | - Michael J McKenna
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - David J Bishop
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Richard B Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX, USA
| | - Jeffrey R Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, USA
| | - Douglas S Kalman
- Nutrion Department, College of Osteopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314, USA
- Scientific Affairs. Nutrasource, Guelph, ON, Canada
| | - Shawn M Arent
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
| | - Trisha A VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA, USA
| | - Hector L Lopez
- The Center for Applied Health Sciences, Stow, OH, USA
- Supplement Safety Solutions, Bedford, MA, 01730, USA
| | | | - Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - Jose Antonio
- Exercise and Sport Science, Nova Southeastern University, Davie, FL, 33314, USA
| | - Bill I Campbell
- Performance & Physique Enhancement Laboratory, University of South Florida, Tampa, FL, 33612, USA
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10
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Effects of Caffeine on Resistance Exercise: A Review of Recent Research. Sports Med 2021; 51:2281-2298. [PMID: 34291426 DOI: 10.1007/s40279-021-01521-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2021] [Indexed: 02/06/2023]
Abstract
In the last few years, a plethora of studies have explored the effects of caffeine on resistance exercise, demonstrating that this field of research is growing fast. This review evaluates and summarizes the most recent findings. Given that toxic doses of caffeine are needed to increase skeletal muscle contractility, the binding of caffeine to adenosine receptors is likely the primary mechanism for caffeine's ergogenic effects on resistance exercise. There is convincing evidence that caffeine ingestion is ergogenic for (i) one-repetition maximum, isometric, and isokinetic strength; and (ii) muscular endurance, velocity, and power in different resistance exercises, loads, and set protocols. Furthermore, there is some evidence that caffeine supplementation also may enhance adaptations to resistance training, such as gains in strength and power. Caffeine ingestion is ergogenic for resistance exercise performance in females, and the magnitude of these effects seems to be similar to that observed in men. Habitual caffeine intake and polymorphisms within CYP1A2 and ADORA2A do not seem to modulate caffeine's ergogenic effects on resistance exercise. Consuming lower doses of caffeine (e.g., 2-3 mg/kg) appears to be comparably ergogenic to consuming high doses of caffeine (e.g., 6 mg/kg). Minimal effective doses of caffeine seem to be around 1.5 mg/kg. Alternate caffeine sources such as caffeinated chewing gum, gel, and coffee are also ergogenic for resistance exercise performance. With caffeine capsules, the optimal timing of ingestion seems to be 30-60 min before exercise. Caffeinated chewing gums and gels may enhance resistance exercise performance even when consumed 10 min before exercise. It appears that caffeine improves performance in resistance exercise primarily due to its physiological effects. Nevertheless, a small portion of the ergogenic effect of caffeine seems to be placebo-driven.
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