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Yalcinkaya N, Isik O, Beyleroglu M, Erdogdu D, Cicek G, Novak D. Effects of 8-week alkaline diet and aerobic exercise on body composition, aerobic performance, and lipid profiles in sedentary women. Front Nutr 2024; 10:1339874. [PMID: 38239837 PMCID: PMC10794351 DOI: 10.3389/fnut.2023.1339874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/12/2023] [Indexed: 01/22/2024] Open
Abstract
Background Diet composition can affect systemic pH and acid-base regulation, which may in turn influence exercise performance. Purpose It was aimed to determine the effects of the alkaline diet and 8 weeks of aerobic exercises on body composition, aerobic performance, and blood lipid profiles in sedentary women. Methods Thirty-two sedentary women participated in the study voluntarily. The research was designed with a true-experimental design and the participants were divided into four different groups as the control group, aerobic exercise group, alkaline diet group, and alkaline diet + aerobic exercise group. The body compositions, aerobic exercise performances, and lipid profiles of sedentary women were measured as pre-test and post-test. In the analysis of the obtained data, One-Way ANOVA with Bonferroni post hoc test was used. Results It was observed that the alkaline diet consumed with 8 weeks of aerobic exercises caused a 5.17% decrease in BMI and an increase of 42.07 and 37.62% in VO2max and aerobic test durations, respectively (p < 0.05). In addition, when lipid profiles were examined, it was determined that there was no statistically significant difference in HDL-C levels (p > 0.05). Despite that, there were statistically significant differences in TG and LDL-C levels (p < 0.05). According to this result, it was determined that there was a decrease in TG and LDL-C levels by 37.61 and 20.24%, respectively. Conclusion An alkaline diet consumed with 8 weeks of aerobic exercises in sedentary women has positive effects on improving body composition, aerobic exercise performances, and TG and LDL-C levels.
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Affiliation(s)
- Nehir Yalcinkaya
- Faculty of Sports Sciences, Sakarya University of Applied Sciences, Sakarya, Türkiye
| | - Ozkan Isik
- Faculty of Sports Sciences, Balıkesir University, Balikesir, Türkiye
- Directorate of Sports Sciences Application and Research Center, Balikesir University, Balikesir, Türkiye
| | - Malik Beyleroglu
- Faculty of Sports Sciences, Sakarya University of Applied Sciences, Sakarya, Türkiye
| | | | - Guner Cicek
- Faculty of Sports Sciences, Hitit University, Çorum, Türkiye
| | - Dario Novak
- University of Zagreb Faculty of Kinesiology, Zagreb, Croatia
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Foster C, Hanley B, Barroso R, Boullosa D, Casado A, Haugen T, Hettinga FJ, Jones AM, Renfree A, Skiba P, St Clair Gibson A, Thiel C, de Koning JJ. Evolution of 1500-m Olympic Running Performance. Int J Sports Physiol Perform 2024; 19:62-70. [PMID: 37922897 DOI: 10.1123/ijspp.2023-0289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/19/2023] [Accepted: 09/27/2023] [Indexed: 11/07/2023]
Abstract
PURPOSE This study determined the evolution of performance and pacing for each winner of the men's Olympic 1500-m running track final from 1924 to 2020. METHODS Data were obtained from publicly available sources. When official splits were unavailable, times from sources such as YouTube were included and interpolated from video records. Final times, lap splits, and position in the peloton were included. The data are presented relative to 0 to 400 m, 400 to 800 m, 800 to 1200 m, and 1200 to 1500 m. Critical speed and D' were calculated using athletes' season's best times. RESULTS Performance improved ∼25 seconds from 1924 to 2020, with most improvement (∼19 s) occurring in the first 10 finals. However, only 2 performances were world records, and only one runner won the event twice. Pacing evolved from a fast start-slow middle-fast finish pattern (reverse J-shaped) to a slower start with steady acceleration in the second half (J-shaped). The coefficient of variation for lap speeds ranged from 1.4% to 15.3%, consistent with a highly tactical pacing pattern. With few exceptions, the eventual winners were near the front throughout, although rarely in the leading position. There is evidence of a general increase in both critical speed and D' that parallels performance. CONCLUSIONS An evolution in the pacing pattern occurred across several "eras" in the history of Olympic 1500-m racing, consistent with better trained athletes and improved technology. There has been a consistent tactical approach of following opponents until the latter stages, and athletes should develop tactical flexibility, related to their critical speed and D', in planning prerace strategy.
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Affiliation(s)
- Carl Foster
- University of Wisconsin-La Crosse, La Crosse, WI, USA
| | | | | | | | | | | | | | | | | | - Philip Skiba
- University of Exeter, Exeter, UK
- Advocate Lutheran General Hospital, Park Ridge, IL, USA
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Carr AJ, McKay AKA, Burke LM, Smith ES, Urwin CS, Convit L, Jardine WT, Kelly MK, Saunders B. Use of Buffers in Specific Contexts: Highly Trained Female Athletes, Extreme Environments and Combined Buffering Agents-A Narrative Review. Sports Med 2023; 53:25-48. [PMID: 37878211 PMCID: PMC10721675 DOI: 10.1007/s40279-023-01872-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2023] [Indexed: 10/26/2023]
Abstract
This narrative review evaluated the evidence for buffering agents (sodium bicarbonate, sodium citrate and beta-alanine), with specific consideration of three discrete scenarios: female athletes, extreme environments and combined buffering agents. Studies were screened according to exclusion and inclusion criteria and were analysed on three levels: (1) moderating variables (supplement dose and timing, and exercise test duration and intensity), (2) design factors (e.g., use of crossover or matched group study design, familiarisation trials) and (3) athlete-specific factors (recruitment of highly trained participants, buffering capacity and reported performance improvements). Only 19% of the included studies for the three buffering agents reported a performance benefit, and only 10% recruited highly trained athletes. This low transferability of research findings to athletes' real-world practices may be due to factors including the small number of sodium citrate studies in females (n = 2), no studies controlling for the menstrual cycle (MC) or menstrual status using methods described in recently established frameworks, and the limited number of beta-alanine studies using performance tests replicating real-world performance efforts (n = 3). We recommend further research into buffering agents in highly trained female athletes that control or account for the MC, studies that replicate the demands of athletes' heat and altitude camps, and investigations of highly trained athletes' use of combined buffering agents. In a practical context, we recommend developing evidence-based buffering protocols for individual athletes which feature co-supplementation with other evidence-based products, reduce the likelihood of side-effects, and optimise key moderating factors: supplement dose and timing, and exercise duration and intensity.
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Affiliation(s)
- Amelia J Carr
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia.
| | - Alannah K A McKay
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Louise M Burke
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Ella S Smith
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Charles S Urwin
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Lilia Convit
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - William T Jardine
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Monica K Kelly
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Bryan Saunders
- Applied Physiology and Nutrition Research Group, Rheumatology Division, Faculdade de Medicina FMUSP, School of Physical Education and Sport, Universidade de São Paulo, University of São Paulo, São Paulo, Brazil
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil
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Leach NK, Hilton NP, Tinnion D, Dobson B, McNaughton LR, Sparks SA. Sodium Bicarbonate Ingestion in a Fasted State Improves 16.1-km Cycling Time-Trial Performance. Med Sci Sports Exerc 2023; 55:2299-2307. [PMID: 37535313 DOI: 10.1249/mss.0000000000003263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
PURPOSE The use of sodium bicarbonate (SB) as a preexercise ergogenic aid has been extensively studied in short-duration high-intensity exercise. Very few studies have considered the effects of SB ingestion before prolonged high-intensity exercise. The aim of the present study was to determine the effects of a 0.3 g·kg -1 body mass dose of SB ingested before the start of a 16.1-km cycling time trial in cyclists. METHOD Ten trained male cyclists (age, 31.1 ± 9 yr; height, 1.84 ± 0.05 m; body mass, 82.8 ± 8.5 kg; and V̇O 2peak , 60.4 ± 3.1 mL·kg -1 ·min -1 ) completed this study. Participants ingested 0.3 g·kg -1 in gelatine (SB-G) and enteric capsules (SB-E) 1 wk apart to determine individualized time-to-peak alkalosis for each ingestion form. Using a randomized crossover design, participants then performed simulated 16.1-km time trials after ingestion of SB-G, SB-E, or a placebo. RESULTS There were significant differences in performance between the SB and placebo ingestion strategies ( f = 5.50, P = 0.014, p η2 = 0.38). Performance time was significantly improved by SB ingestion (mean improvement: 34.4 ± 42.6 s ( P = 0.031) and 40.4 ± 45.5 s ( P = 0.020) for SB-G and SB-E, respectively) compared with the placebo. Gastrointestinal symptoms were lower after SB-E compared with SB-G (36.3 ± 4.5 vs 5.6 ± 3.1 AU, P < 0.001, g = 7.09). CONCLUSIONS This study demonstrates that increased buffering capacity after acute preexercise SB ingestion can improve endurance cycling time-trial performances. The use of SB could be considered for use in 16.1-km cycling time trials, but further work is required to establish these effects after a preexercise meal.
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Affiliation(s)
- Nicholas K Leach
- Sport Performance, Exercise and Nutrition Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, UNITED KINGDOM
| | - Nathan P Hilton
- Edge Hill University Medical School, Faculty of Health, Social Care & Medicine, Edge Hill University, Ormskirk, UNITED KINGDOM
| | - Daniel Tinnion
- Sport Performance, Exercise and Nutrition Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, UNITED KINGDOM
| | - Ben Dobson
- Sport Performance, Exercise and Nutrition Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, UNITED KINGDOM
| | - Lars R McNaughton
- Sport Performance, Exercise and Nutrition Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, UNITED KINGDOM
| | - S Andy Sparks
- Sport Performance, Exercise and Nutrition Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, UNITED KINGDOM
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Interaction of Factors Determining Critical Power. Sports Med 2023; 53:595-613. [PMID: 36622556 PMCID: PMC9935749 DOI: 10.1007/s40279-022-01805-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2022] [Indexed: 01/10/2023]
Abstract
The physiological determinants of high-intensity exercise tolerance are important for both elite human performance and morbidity, mortality and disease in clinical settings. The asymptote of the hyperbolic relation between external power and time to task failure, critical power, represents the threshold intensity above which systemic and intramuscular metabolic homeostasis can no longer be maintained. After ~ 60 years of research into the phenomenon of critical power, a clear understanding of its physiological determinants has emerged. The purpose of the present review is to critically examine this contemporary evidence in order to explain the physiological underpinnings of critical power. Evidence demonstrating that alterations in convective and diffusive oxygen delivery can impact upon critical power is first addressed. Subsequently, evidence is considered that shows that rates of muscle oxygen utilisation, inferred via the kinetics of pulmonary oxygen consumption, can influence critical power. The data reveal a clear picture that alterations in the rates of flux along every step of the oxygen transport and utilisation pathways influence critical power. It is also clear that critical power is influenced by motor unit recruitment patterns. On this basis, it is proposed that convective and diffusive oxygen delivery act in concert with muscle oxygen utilisation rates to determine the intracellular metabolic milieu and state of fatigue within the myocytes. This interacts with exercising muscle mass and motor unit recruitment patterns to ultimately determine critical power.
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Richard NA, Koehle MS. Influence and Mechanisms of Action of Environmental Stimuli on Work Near and Above the Severe Domain Boundary (Critical Power). SPORTS MEDICINE - OPEN 2022; 8:42. [PMID: 35347469 PMCID: PMC8960528 DOI: 10.1186/s40798-022-00430-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 02/26/2022] [Indexed: 11/10/2022]
Abstract
Abstract
The critical power (CP) concept represents the uppermost rate of steady state aerobic metabolism during work. Work above CP is limited by a fixed capacity (W′) with exercise intensity being an accelerant of its depletion rate. Exercise at CP is a considerable insult to homeostasis and any work done above it will rapidly become intolerable. Humans live and exercise in situations of hypoxia, heat, cold and air pollution all of which impose a new environmental stress in addition to that of exercise. Hypoxia disrupts the oxygen cascade and consequently aerobic energy production, whereas heat impacts the circulatory system’s ability to solely support exercise performance. Cold lowers efficiency and increases the metabolic cost of exercise, whereas air pollution negatively impacts the respiratory system. This review will examine the effects imposed by environmental conditions on CP and W′ and describe the key physiological mechanisms which are affected by the environment.
Graphical Abstract
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Gough LA, Williams JJ, Newbury JW, Gurton WH. The effects of sodium bicarbonate supplementation at individual time-to-peak blood bicarbonate on 4-km cycling time trial performance in the heat. Eur J Sport Sci 2022; 22:1856-1864. [PMID: 34704539 DOI: 10.1080/17461391.2021.1998644] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The purpose of this study was to explore the effect of individualised sodium bicarbonate (NaHCO3) supplementation according to a pre-established individual time-to-peak (TTP) blood bicarbonate (HCO3-) on 4-km cycling time trial (TT) performance in the heat. Eleven recreationally trained male cyclists (age: 28 ± 6 years, height: 180 ± 6 cm, body mass: 80.5 ± 8.4 kg) volunteered for this study in a randomised, crossover, triple-blind, placebo-controlled design. An initial visit was conducted to determine TTP HCO3- following 0.2 g.kg-1 body mass (BM) NaHCO3 ingestion. Subsequently, on three separate occasions, participants completed a 4-km cycling TT in the heat (30 degrees centigrade; °C) (relative humidity ∼40%) following ingestion of either NaHCO3 (0.2 g.kg-1 body mass), a sodium chloride placebo (0.2 g.kg-1 BM; PLA) at the predetermined individual TTP HCO3-, or no supplementation (control; CON) . Absolute peak [HCO3-] prior to the 4-km cycling TT's was elevated for NaHCO3 compared to PLA (+2.8 mmol.l-1; p = 0.002; g = 2.2) and CON (+2.5 mmol.l-1; p < 0.001; g = 2.1). Completion time following NaHCO3 was 5.6 ± 3.2 s faster than PLA (1.6%; CI: 2.8, 8.3; p = 0.001; g = 0.2) and 4.7 ± 2.8 s faster than CON (1.3%; CI: 2.3, 7.1; p = 0.001; g = 0.2). These results demonstrate that NaHCO3 ingestion at a pre-established individual TTP HCO3- improves 4-km cycling TT performance in the heat, likely through enhancing buffering capacity.Highlights This is the first time NaHCO3 ingestion has been shown to improve 4-km cycling TT performance in conditions of high ambient heat.A smaller dose of NaHCO3 (0.2 g.kg-1 BM) is ergogenic in the heat, which is smaller than the dose typically ingested for sports performance (0.3 g.kg-1 BM). This is important, as gastrointestinal discomfort is typically lower as the dose reduces.This study suggests that the individualised time-to-peak HCO3- ingestion strategy with lower doses of NaHCO3 is an ergogenic strategy in conditions of high ambient heat.
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Affiliation(s)
- Lewis A Gough
- Human Performance and Health Research Group, Centre for Life and Sport Sciences Research Centre, Birmingham City University, Birmingham, UK
| | - Jake J Williams
- Human Performance and Health Research Group, Centre for Life and Sport Sciences Research Centre, Birmingham City University, Birmingham, UK
| | - Josh W Newbury
- Human Performance and Health Research Group, Centre for Life and Sport Sciences Research Centre, Birmingham City University, Birmingham, UK
| | - William H Gurton
- Department of Sport, Exercise and Rehabilitation Sciences, Canterbury Christ Church University, Canterbury, UK
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Lopes-Silva JP, Correia-Oliveira CR. Acute effects of sodium bicarbonate ingestion on cycling time-trial performance: A systematic review and meta-analysis of randomized controlled trials. Eur J Sport Sci 2022; 23:943-954. [PMID: 35633035 DOI: 10.1080/17461391.2022.2071171] [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
This study aimed to investigate the isolated effects of NaHCO3 on cycling time-trial performance. Furthermore, we investigated whether the ingestion time of NaHCO3, standardized or individualized based on time to peak, could be effective in improving cycling time-trial performance. A systematic review was carried out on randomized placebo-controlled studies. A random-effects meta-analysis assessed the standardized mean difference (SMD) between NaHCO3 and placebo conditions. Eighteen studies were qualitatively (systematic review) and quantitatively (meta-analysis) analysed concerning mean power output (Wmean) (n = 182) and time performance (n = 201). The reviewed studies showed a low risk of bias and homogenous results for Wmean (I2 = 0%) and performance time (I2 = 0%). Overall, when compared to placebo, the NaHCO3 ingestion improved the Wmean (SMD: 0.42; 95% CI: 0.21-0.63; P = 0.001) and performance time (SMD: 0.22; 95% CI: 0.02-0.43; P = 0.03). Similarly, the NaHCO3 ingestion using a time-to-peak strategy improved the Wmean (SMD: 0.39; 95% CI: 0.03-0.75; P = 0.04; I2 = 15%) and performance time (SMD: 0.34; 95% CI: 0.07-0.61, P = 0.01, I2 = 0%). The present findings reveal that NaHCO3 ingestion has the potential to increase the overall performance time and Wmean in cycling time trials. HighlightsNaHCO3 is an effective strategy to increase cycling time-trial performance.The standardized protocol did not improve the cycling time-trial performance parameters.The individualized time-to-peak NaHCO3 ingestion has a positive effect on time and Wmean during cycling time-trial performance.
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Affiliation(s)
- João Paulo Lopes-Silva
- Applied Research Group to Performance and Health, CESMAC University Center, Maceió, 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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Poffé C, Robberechts R, Podlogar T, Kusters M, Debevec T, Hespel P. Exogenous ketosis increases blood and muscle oxygenation but not performance during exercise in hypoxia. Am J Physiol Regul Integr Comp Physiol 2021; 321:R844-R857. [PMID: 34668436 DOI: 10.1152/ajpregu.00198.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Available evidence indicates that elevated blood ketones are associated with improved hypoxic tolerance in rodents. From this perspective, we hypothesized that exogenous ketosis by oral intake of the ketone ester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (KE) may induce beneficial physiological effects during prolonged exercise in acute hypoxia. As we recently demonstrated KE to deplete blood bicarbonate, which per se may alter the physiological response to hypoxia, we evaluated the effect of KE both in the presence and absence of bicarbonate intake (BIC). Fourteen highly trained male cyclists performed a simulated cycling race (RACE) consisting of 3-h intermittent cycling (IMT180') followed by a 15-min time-trial (TT15') and an all-out sprint at 175% of lactate threshold (SPRINT). During RACE, fraction of inspired oxygen ([Formula: see text]) was gradually decreased from 18.6% to 14.5%. Before and during RACE, participants received either 1) 75 g of ketone ester (KE), 2) 300 mg/kg body mass bicarbonate (BIC), 3) KE + BIC, or 4) a control drink in addition to 60 g of carbohydrates/h in a randomized, crossover design. KE counteracted the hypoxia-induced drop in blood ([Formula: see text]) and muscle oxygenation by ∼3%. In contrast, BIC decreased [Formula: see text] by ∼2% without impacting muscle oxygenation. Performance during TT15' and SPRINT were similar between all conditions. In conclusion, KE slightly elevated the degree of blood and muscle oxygenation during prolonged exercise in moderate hypoxia without impacting exercise performance. Our data warrant to further investigate the potential of exogenous ketosis to improve muscular and cerebral oxygenation status, and exercise tolerance in extreme hypoxia.
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Affiliation(s)
- Chiel Poffé
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Ruben Robberechts
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Tim Podlogar
- Department for Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Faculty of Health Sciences, University of Primorska, Izola, Slovenia
| | - Martijn Kusters
- Bakala Academy-Athletic Performance Center, KU Leuven, Leuven, Belgium
| | - Tadej Debevec
- Department for Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - Peter Hespel
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium.,Bakala Academy-Athletic Performance Center, KU Leuven, Leuven, Belgium
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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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12
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Johnson MA, Sharpe GR, Needham RS, Williams NC. Effects of Prior Voluntary Hyperventilation on the 3-min All-Out Cycling Test in Men. Med Sci Sports Exerc 2021; 53:1482-1494. [PMID: 33481485 DOI: 10.1249/mss.0000000000002608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The ergogenic effects of respiratory alkalosis induced by prior voluntary hyperventilation (VH) are controversial. This study examined the effects of prior VH on derived parameters from the 3-min all-out cycling test (3MT). METHODS Eleven men ( = 46 ± 8 mL·kg-1·min-1) performed a 3MT preceded by 15 min of rest (CONT) or VH ( = 38 ± 5 L·min-1) with PETCO2 reduced to 21 ± 1 mm Hg (HYP). End-test power (EP; synonymous with critical power) was calculated as the mean power output over the last 30 s of the 3MT, and the work done above EP (WEP; synonymous with W') was calculated as the power-time integral above EP. RESULTS At the start of the 3MT, capillary blood PCO2 and [H+] were lower in HYP (25.2 ± 3.0 mm Hg, 27.1 ± 2.6 nmol·L-1) than CONT (43.2 ± 2.0 mm Hg, 40.0 ± 1.5 nmol·L-1) (P < 0.001). At the end of the 3MT, blood PCO2 was still lower in HYP (35.7 ± 5.4 mm Hg) than CONT (40.6 ± 5.0 mm Hg) (P < 0.001). WEP was 10% higher in HYP (19.4 ± 7.0 kJ) than CONT (17.6 ± 6.4 kJ) (P = 0.006), whereas EP was 5% lower in HYP (246 ± 69 W) than CONT (260 ± 74 W) (P = 0.007). The ΔWEP (J·kg-1) between CONT and HYP correlated positively with the PCO2 immediately before the 3MT in HYP (r = 0.77, P = 0.006). CONCLUSION These findings suggest that acid-base changes elicited by prior VH increase WEP but decrease EP during the all-out 3MT.
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Affiliation(s)
- Michael A Johnson
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, UNITED KINGDOM
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13
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Calvo JL, Xu H, Mon-López D, Pareja-Galeano H, Jiménez SL. Effect of sodium bicarbonate contribution on energy metabolism during exercise: a systematic review and meta-analysis. J Int Soc Sports Nutr 2021; 18:11. [PMID: 33546730 PMCID: PMC7863495 DOI: 10.1186/s12970-021-00410-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
Background The effects of sodium bicarbonate (NaHCO3) on anaerobic and aerobic capacity are commonly acknowledged as unclear due to the contrasting evidence thus, the present study analyzes the contribution of NaHCO3 to energy metabolism during exercise. Methods Following a search through five databases, 17 studies were found to meet the inclusion criteria. Meta-analyses of standardized mean differences (SMDs) were performed using a random-effects model to determine the effects of NaHCO3 supplementation on energy metabolism. Subgroup meta-analyses were conducted for the anaerobic-based exercise (assessed by changes in pH, bicarbonate ion [HCO3−], base excess [BE] and blood lactate [BLa]) vs. aerobic-based exercise (assessed by changes in oxygen uptake [VO2], carbon dioxide production [VCO2], partial pressure of oxygen [PO2] and partial pressure of carbon dioxide [PCO2]). Results The meta-analysis indicated that NaHCO3 ingestion improves pH (SMD = 1.38, 95% CI: 0.97 to 1.79, P < 0.001; I2 = 69%), HCO3− (SMD = 1.63, 95% CI: 1.10 to 2.17, P < 0.001; I2 = 80%), BE (SMD = 1.67, 95% CI: 1.16 to 2.19, P < 0.001, I2 = 77%), BLa (SMD = 0.72, 95% CI: 0.34 to 1.11, P < 0.001, I2 = 68%) and PCO2 (SMD = 0.51, 95% CI: 0.13 to 0.90, P = 0.009, I2 = 0%) but there were no differences between VO2, VCO2 and PO2 compared with the placebo condition. Conclusions This meta-analysis has found that the anaerobic metabolism system (AnMS), especially the glycolytic but not the oxidative system during exercise is affected by ingestion of NaHCO3. The ideal way is to ingest it is in a gelatin capsule in the acute mode and to use a dose of 0.3 g•kg− 1 body mass of NaHCO3 90 min before the exercise in which energy is supplied by the glycolytic system.
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Affiliation(s)
- Jorge Lorenzo Calvo
- Faculty of Physical Activity and Sport science, Universidad Politécnica de Madrid, Madrid, Spain.
| | - Huanteng Xu
- Faculty of Sport Sciences, Universidad Europea de Madrid, Madrid, Spain.
| | - Daniel Mon-López
- Faculty of Physical Activity and Sport science, Universidad Politécnica de Madrid, Madrid, Spain
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14
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Effect of Carbohydrate-Electrolyte Solution Including Bicarbonate Ion Ad Libitum Ingestion on Urine Bicarbonate Retention during Mountain Trekking: A Randomized, Controlled Pilot Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041441. [PMID: 33557035 PMCID: PMC7913653 DOI: 10.3390/ijerph18041441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 11/16/2022]
Abstract
We investigated whether bicarbonate ion (HCO3−) in a carbohydrate-electrolyte solution (CE+HCO3) ingested during climbing to 3000 m on Mount Fuji could increase urine HCO3− retention. This study was a randomized, controlled pilot study. Sixteen healthy lowlander adults were divided into two groups (six males and two females for each): a tap water (TW) group (0 kcal with no energy) and a CE+HCO3 group. The allocation to TW or CE+HCO3 was double blind. The CE solution contains 10 kcal energy, including Na+ (115 mg), K+ (78 mg), HCO3− (51 mg) per 100 mL. After collecting baseline urine and measuring body weight, participants started climbing while energy expenditure (EE) and heart rate (HR) were recorded every min with a portable calorimeter. After reaching a hut at approximately 3000 m, we collected urine and measured body weight again. The HCO3− balance during climbing, measured by subtracting the amount of urine excreted from the amount of fluid ingested, was −0.37 ± 0.77 mmol in the CE+HCO3, which was significantly higher than in the TW (−2.23 ± 0.96 mmol, p < 0.001). These results indicate that CE containing HCO3− supplementation may increase the bicarbonate buffering system during mountain trekking up to ~3000 m, suggesting a useful solution, at least, in the population of the present study on Mount Fuji.
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15
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Patel KA, Farias de Oliveira L, Sale C, James RM. The effect of β-alanine supplementation on high intensity cycling capacity in normoxia and hypoxia. J Sports Sci 2021; 39:1295-1301. [PMID: 33491594 DOI: 10.1080/02640414.2020.1867416] [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: 10/22/2022]
Abstract
The availability of dietary beta-alanine (BA) is the limiting factor in carnosine synthesis within human muscle due to its low intramuscular concentration and substrate affinity. Carnosine can accept hydrogen ions (H+), making it an important intramuscular buffer against exercise-induced acidosis. Metabolite accumulation rate increases when exercising in hypoxic conditions, thus an increased carnosine concentration could attenuate H+ build-up when exercising in hypoxic conditions. This study examined the effects of BA supplementation on high intensity cycling capacity in normoxia and hypoxia. In a double-blind design, nineteen males were matched into a BA group (n = 10; 6.4 g·d-1) or a placebo group (PLA; n = 9) and supplemented for 28 days, carrying out two pre- and two post-supplementation cycling capacity trials at 110% of powermax, one in normoxia and one in hypoxia (15.5% O2). Hypoxia led to a 9.1% reduction in exercise capacity, but BA supplementation had no significant effect on exercise capacity in normoxia or hypoxia (P > 0.05). Blood lactate accumulation showed a significant trial x time interaction post-supplementation (P = 0.016), although this was not significantly different between groups. BA supplementation did not increase high intensity cycling capacity in normoxia, nor did it improve cycling capacity in hypoxia even though exercise capacity was reduced under hypoxic conditions.
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Affiliation(s)
- Kiran Akshay Patel
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Luana Farias de Oliveira
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Craig Sale
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Ruth M James
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
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16
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Limmer M, de Marées M, Platen P. Alterations in acid-base balance and high-intensity exercise performance after short-term and long-term exposure to acute normobaric hypoxic conditions. Sci Rep 2020; 10:13732. [PMID: 32792614 PMCID: PMC7426914 DOI: 10.1038/s41598-020-70762-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 08/04/2020] [Indexed: 11/21/2022] Open
Abstract
This investigation assessed the course of renal compensation of hypoxia-induced respiratory alkalosis by elimination of bicarbonate ions and impairments in anaerobic exercise after different durations of hypoxic exposure. Study A: 16 participants underwent a resting 12-h exposure to normobaric hypoxia (3,000 m). Blood gas analysis was assessed hourly. While blood pH was significantly increased, PO2, PCO2, and SaO2 were decreased within the first hour of hypoxia, and changes remained consistent. A substantial reduction in [HCO3-] levels was observed after 12 h of hypoxic exposure (- 1.35 ± 0.29 mmol/L, p ≤ 0.05). Study B: 24 participants performed in a randomized, cross-over trial portable tethered sprint running (PTSR) tests under normoxia and after either 1 h (n = 12) or 12 h (n = 12) of normobaric hypoxia (3,000 m). No differences occurred for PTSR-related performance parameters, but the reduction in blood lactate levels was greater after 12 h compared with 1 h (- 1.9 ± 2.2 vs 0.0 ± 2.3 mmol/L, p ≤ 0.05). These results indicate uncompensated respiratory alkalosis after 12 h of hypoxia and similar impairment of high-intensity exercise after 1 and 12 h of hypoxic exposure, despite a greater reduction in blood lactate responses after 12 h compared with 1 h of hypoxic exposure.
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Affiliation(s)
- Mirjam Limmer
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany.
- Institute of Outdoor Sports and Environmental Science, German Sports University Cologne, Cologne, Germany.
| | - Markus de Marées
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany
| | - Petra Platen
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany
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17
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Nutrition and Altitude: Strategies to Enhance Adaptation, Improve Performance and Maintain Health: A Narrative Review. Sports Med 2020; 49:169-184. [PMID: 31691928 PMCID: PMC6901429 DOI: 10.1007/s40279-019-01159-w] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Training at low to moderate altitudes (~ 1600-2400 m) is a common approach used by endurance athletes to provide a distinctive environmental stressor to augment training stimulus in the anticipation of increasing subsequent altitude- and sea-level-based performance. Despite some scientific progress being made on the impact of various nutrition-related changes in physiology and associated interventions at mountaineering altitudes (> 3000 m), the impact of nutrition and/or supplements on further optimization of these hypoxic adaptations at low-moderate altitudes is only an emerging topic. Within this narrative review we have highlighted six major themes involving nutrition: altered energy availability, iron, carbohydrate, hydration, antioxidant requirements and various performance supplements. Of these issues, emerging data suggest that particular attention be given to the potential risk for poor energy availability and increased iron requirements at the altitudes typical of elite athlete training (~ 1600-2400 m) to interfere with optimal adaptations. Furthermore, the safest way to address the possible increase in oxidative stress associated with altitude exposure is via the consumption of antioxidant-rich foods rather than high-dose antioxidant supplements. Meanwhile, many other important questions regarding nutrition and altitude training remain to be answered. At the elite level of sport where the differences between winning and losing are incredibly small, the strategic use of nutritional interventions to enhance the adaptations to altitude training provides an important consideration in the search for optimal performance.
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18
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Limmer M, de Marées M, Platen P. Effects of daily ingestion of sodium bicarbonate on acid-base status and anaerobic performance during an altitude sojourn at high altitude: a randomized controlled trial. J Int Soc Sports Nutr 2020; 17:22. [PMID: 32307012 PMCID: PMC7168960 DOI: 10.1186/s12970-020-00351-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/03/2020] [Indexed: 01/18/2023] Open
Abstract
Background The present study investigated the effects of chronic sodium bicarbonate (NaHCO3) ingestion on a single bout of high-intensity exercise and on acid-base balance during 7-day high-altitude exposure. Methods Ten recreationally active subjects participated in a pre-test at sea level and a 7-day hiking tour in the Swiss Alps up to 4554 m above sea level. Subjects received either a daily dose of 0.3 g/kg NaHCO3 solution (n = 5) or water as a placebo (n = 5) for 7 days. Anaerobic high-intensity exercise performance was assessed using the portable tethered sprint running (PTSR) test under normoxic and hypoxic conditions (3585 m). PTSR tests assessed overall peak force, mean force, and fatigue index. Blood lactate levels and blood gas parameters were assessed pre- and post-PTSR. Urinary pH and blood gas parameters were further analyzed daily at rest in early morning samples under normoxic and hypoxic conditions. Results There were no significant differences between the bicarbonate and control group in any of the PTSR-related parameters. However, urinary pH (p = 0.003, ηp2 = 0.458), early morning blood bicarbonate concentration (p < 0.001, ηp2 = 0.457) and base excess (p = 0.002, ηp2 = 0.436) were significantly higher in the bicarbonate group compared with the control group under hypoxic conditions. Conclusions These results indicate that oral NaHCO3 ingestion does not ameliorate the hypoxia-induced impairment in anaerobic, high-intensity exercise performance, represented by PTSR-related test parameters, under hypobaric, hypoxic conditions, but the maximal performance measurements may have been negatively affected by other factors, such as poor implementation of PTSR test instructions, pre-acclimatization, the time course of hypoxia-induced renal [HCO3−] compensation, changes in the concentrations of intra- and extracellular ions others than [H+] and [HCO3−], or gastrointestinal disturbances caused by NaHCO3 ingestion. However, chronic NaHCO3 ingestion improves blood bicarbonate concentration and base excess at altitude, which partially represent the blood buffering capacity.
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Affiliation(s)
- Mirjam Limmer
- Department of Sports Medicine and Sports Nutrition, Ruhr-Universität Bochum, Gesundheitscampus Nord 10, 44801, Bochum, Germany. .,Institute of Outdoor Sports and Environmental Science, German Sport University Cologne, Cologne, Germany.
| | - Markus de Marées
- Department of Sports Medicine and Sports Nutrition, Ruhr-Universität Bochum, Gesundheitscampus Nord 10, 44801, Bochum, Germany
| | - Petra Platen
- Department of Sports Medicine and Sports Nutrition, Ruhr-Universität Bochum, Gesundheitscampus Nord 10, 44801, Bochum, Germany
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19
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Effects of an Alkalizing or Acidizing Diet on High-Intensity Exercise Performance under Normoxic and Hypoxic Conditions in Physically Active Adults: A Randomized, Crossover Trial. Nutrients 2020; 12:nu12030688. [PMID: 32143278 PMCID: PMC7146607 DOI: 10.3390/nu12030688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/29/2020] [Accepted: 03/02/2020] [Indexed: 12/17/2022] Open
Abstract
Pre-alkalization caused by dietary supplements such as sodium bicarbonate improves anaerobic exercise performance. However, the influence of a base-forming nutrition on anaerobic performance in hypoxia remains unknown. Herein, we investigated the effects of an alkalizing or acidizing diet on high-intensity performance and associated metabolic parameters in normoxia and hypoxia. In a randomized crossover design, 15 participants (24.5 ± 3.9 years old) performed two trials following four days of either an alkalizing (BASE) or an acidizing (ACID) diet in normoxia. Subsequently, participants performed two trials (BASE; ACID) after 12 h of normobaric hypoxic exposure. Anaerobic exercise performance was assessed using the portable tethered sprint running (PTSR) test. PTSR assessed overall peak force, mean force, and fatigue index. Blood lactate levels, blood gas parameters, heart rate, and rate of perceived exertion were assessed post-PTSR. Urinary pH was analyzed daily. There were no differences between BASE and ACID conditions for any of the PTSR-related parameters. However, urinary pH, blood pH, blood bicarbonate concentration, and base excess were significantly higher in BASE compared with ACID (p < 0.001). These findings show a diet-induced increase in blood buffer capacity, represented by blood bicarbonate concentration and base excess. However, diet-induced metabolic changes did not improve PTSR-related anaerobic performance.
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20
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Gough LA, Deb SK, Brown D, Sparks SA, McNaughton LR. The effects of sodium bicarbonate ingestion on cycling performance and acid base balance recovery in acute normobaric hypoxia. J Sports Sci 2019; 37:1464-1471. [PMID: 30668281 DOI: 10.1080/02640414.2019.1568173] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study investigated the effects of two separate doses of sodium bicarbonate (NaHCO3) on 4 km time trial (TT) cycling performance and post-exercise acid base balance recovery in hypoxia. Fourteen club-level cyclists completed four cycling TT's, followed by a 40 min passive recovery in normobaric hypoxic conditions (FiO2 = 14.5%) following one of either: two doses of NaHCO3 (0.2 g.kg-1 BM; SBC2, or 0.3 g.kg-1 BM; SBC3), a taste-matched placebo (0.07 g.kg-1 BM sodium chloride; PLA), or a control trial in a double-blind, randomized, repeated-measures and crossover design study. Compared to PLA, TT performance was improved following SBC2 (p = 0.04, g = 0.16, very likely beneficial), but was improved to a greater extent following SBC3 (p = 0.01, g = 0.24, very likely beneficial). Furthermore, a likely benefit of ingesting SBC3 over SBC2 was observed (p = 0.13, g = 0.10), although there was a large inter-individual variation. Both SBC treatments achieved full recovery within 40 min, which was not observed in either PLA or CON following the TT. In conclusion, NaHCO3 improves 4 km TT performance and acid base balance recovery in acute moderate hypoxic conditions, however the optimal dose warrants an individual approach.
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Affiliation(s)
- Lewis A Gough
- a Sport and Physical Activity Department, Faculty of Health and Life Sciences , Birmingham City University , Birmingham , UK.,b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Sanjoy K Deb
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK.,c Life Sciences Department , University of Westminster , London , UK
| | - Danny Brown
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - S Andy Sparks
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Lars R McNaughton
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK.,d Department of Sport and Movement Studies, Faculty of Health Science , University of Johannesburg , Johannesburg , South Africa
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21
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Puchowicz MJ, Mizelman E, Yogev A, Koehle MS, Townsend NE, Clarke DC. The Critical Power Model as a Potential Tool for Anti-doping. Front Physiol 2018; 9:643. [PMID: 29928234 PMCID: PMC5997808 DOI: 10.3389/fphys.2018.00643] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/11/2018] [Indexed: 11/13/2022] Open
Abstract
Existing doping detection strategies rely on direct and indirect biochemical measurement methods focused on detecting banned substances, their metabolites, or biomarkers related to their use. However, the goal of doping is to improve performance, and yet evidence from performance data is not considered by these strategies. The emergence of portable sensors for measuring exercise intensities and of player tracking technologies may enable the widespread collection of performance data. How these data should be used for doping detection is an open question. Herein, we review the basis by which performance models could be used for doping detection, followed by critically reviewing the potential of the critical power (CP) model as a prototypical performance model that could be used in this regard. Performance models are mathematical representations of performance data specific to the athlete. Some models feature parameters with physiological interpretations, changes to which may provide clues regarding the specific doping method. The CP model is a simple model of the power-duration curve and features two physiologically interpretable parameters, CP and W′. We argue that the CP model could be useful for doping detection mainly based on the predictable sensitivities of its parameters to ergogenic aids and other performance-enhancing interventions. However, our argument is counterbalanced by the existence of important limitations and unresolved questions that need to be addressed before the model is used for doping detection. We conclude by providing a simple worked example showing how it could be used and propose recommendations for its implementation.
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Affiliation(s)
- Michael J Puchowicz
- Department of Health Services, Arizona State University, Tempe, AZ, United States
| | - Eliran Mizelman
- Department of Biomedical Physiology and Kinesiology and Sports Analytics Group, Simon Fraser University, Burnaby, BC, Canada
| | - Assaf Yogev
- School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada
| | - Michael S Koehle
- School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada.,Division of Sport and Exercise Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Nathan E Townsend
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - David C Clarke
- Department of Biomedical Physiology and Kinesiology and Sports Analytics Group, Simon Fraser University, Burnaby, BC, Canada.,Canadian Sport Institute Pacific, Victoria, BC, Canada
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Bertuzzi R, Gáspari AF, Trojbicz LR, Silva-Cavalcante MD, Lima-Silva AE, Billaut F, Girard O, Millet GP, Bossi AH, Hopker J, Pandeló DR, Fulton TJ, Paris HL, Chapman RF, Grosicki GJ, Murach KA, Hureau TJ, Dufour SP, Favret F, Kruse NT, Nicolò A, Sacchetti M, Pedralli M, Pinheiro FA, Tricoli V, Brietzke C, Pires FO, Sandford GN, Pearson S, Kilding AE, Ross A, Laursen PB, da Silveira ALB, Olivares EL, de Azevedo Cruz Seara F, Miguel-dos-Santos R, Mesquita TRR, Nelatury S, Vagula M. Commentaries on Viewpoint: Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength. J Appl Physiol (1985) 2018; 124:529-535. [PMID: 29480788 DOI: 10.1152/japplphysiol.01064.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Romulo Bertuzzi
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil
| | - Arthur F. Gáspari
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil
| | - Lucas R. Trojbicz
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil
| | - Marcos D. Silva-Cavalcante
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil,Sport Science Research Group, Federal University of Pernambuco, Pernambuco, Brazil
| | - Adriano E. Lima-Silva
- Sport Science Research Group, Federal University of Pernambuco, Pernambuco, Brazil,Human Performance Research Group, Technological Federal University of Parana, Parana, Brazil
| | | | - Oliver Girard
- Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Grégoire P. Millet
- Faculty of Biology and Medicine, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Arthur Henrique Bossi
- School of Sport and Exercise Sciences University of Kent, Chatham Maritime, Chatham, Kent, England
| | - James Hopker
- School of Sport and Exercise Sciences University of Kent, Chatham Maritime, Chatham, Kent, England
| | - Domingos R. Pandeló
- Federal University of São Paulo Centro de Alta Performance (High Performance Center)
| | | | | | | | - Gregory J. Grosicki
- Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA
| | - Kevin A. Murach
- Department of Rehabilitation Sciences and Center for Muscle Biology, University of Kentucky, Lexington, KY
| | - Thomas J. Hureau
- University of Strasbourg Faculty of Medicine, Mitochondria, Oxidative Stress and Muscular Protection Laboratory, Strasbourg, France
| | - Stéphane P. Dufour
- University of Strasbourg Faculty of Medicine, Mitochondria, Oxidative Stress and Muscular Protection Laboratory, Strasbourg, France
| | - Fabrice Favret
- University of Strasbourg Faculty of Medicine, Mitochondria, Oxidative Stress and Muscular Protection Laboratory, Strasbourg, France
| | - Nicholas T. Kruse
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa
| | - Andrea Nicolò
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Massimo Sacchetti
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Marinei Pedralli
- Department of Kinesiology & Health Education, Cardiovascular Aging Research Laboratory, The University of Texas at Austin, Austin, TX
| | - Fabiano A. Pinheiro
- Laboratory of Adaptation to Strength Training, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil,Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Valmor Tricoli
- Laboratory of Adaptation to Strength Training, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Cayque Brietzke
- 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
| | - Gareth N. Sandford
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand,High Performance Sport New Zealand, Auckland, New Zealand,Athletics New Zealand, Auckland, New Zealand
| | - Simon Pearson
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand,Queensland Academy of Sport, Nathan, Australia
| | - Andrew E. Kilding
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Angus Ross
- High Performance Sport New Zealand, Auckland, New Zealand,Athletics New Zealand, Auckland, New Zealand
| | - Paul B. Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand,High Performance Sport New Zealand, Auckland, New Zealand
| | - Anderson Luiz B. da Silveira
- Laboratory of Physiology and Human Performance, Department of Physical Education and Sports, Federal Rural University of Rio de Janeiro, Brazil
| | - Emerson Lopes Olivares
- Laboratory of Cardiovascular Physiology and Pharmacology, Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Brazil
| | - Fernando de Azevedo Cruz Seara
- Laboratory of Cardiac Electrophysiology, Carlos Chagas Filho Department of Biophysics, Federal University of Rio de Janeiro, Brazil
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Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions. Eur J Appl Physiol 2018; 118:607-615. [PMID: 29344729 PMCID: PMC5805802 DOI: 10.1007/s00421-018-3801-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 01/02/2018] [Indexed: 12/20/2022]
Abstract
Acute moderate hypoxic exposure can substantially impair exercise performance, which occurs with a concurrent exacerbated rise in hydrogen cation (H+) production. The purpose of this study was therefore, to alleviate this acidic stress through sodium bicarbonate (NaHCO3) supplementation and determine the corresponding effects on severe-intensity intermittent exercise performance. Eleven recreationally active individuals participated in this randomised, double-blind, crossover study performed under acute normobaric hypoxic conditions (FiO2% = 14.5%). Pre-experimental trials involved the determination of time to attain peak bicarbonate anion concentrations ([HCO3−]) following NaHCO3 ingestion. The intermittent exercise tests involved repeated 60-s work in their severe-intensity domain and 30-s recovery at 20 W to exhaustion. Participants ingested either 0.3 g kg bm−1 of NaHCO3 or a matched placebo of 0.21 g kg bm−1 of sodium chloride prior to exercise. Exercise tolerance (+ 110.9 ± 100.6 s; 95% CI 43.3–178 s; g = 1.0) and work performed in the severe-intensity domain (+ 5.8 ± 6.6 kJ; 95% CI 1.3–9.9 kJ; g = 0.8) were enhanced with NaHCO3 supplementation. Furthermore, a larger post-exercise blood lactate concentration was reported in the experimental group (+ 4 ± 2.4 mmol l−1; 95% CI 2.2–5.9; g = 1.8), while blood [HCO3−] and pH remained elevated in the NaHCO3 condition throughout experimentation. In conclusion, this study reported a positive effect of NaHCO3 under acute moderate hypoxic conditions during intermittent exercise and therefore, may offer an ergogenic strategy to mitigate hypoxic induced declines in exercise performance.
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Deb SK, Brown DR, Gough LA, Mclellan CP, Swinton PA, Andy Sparks S, Mcnaughton LR. Quantifying the effects of acute hypoxic exposure on exercise performance and capacity: A systematic review and meta-regression. Eur J Sport Sci 2017; 18:243-256. [PMID: 29220311 DOI: 10.1080/17461391.2017.1410233] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To quantify the effects of acute hypoxic exposure on exercise capacity and performance, which includes continuous and intermittent forms of exercise. DESIGN A systematic review was conducted with a three-level mixed effects meta-regression. The ratio of means method was used to evaluate main effects and moderators providing practical interpretations with percentage change. DATA SOURCES A systemic search was performed using three databases (Google scholar, PubMed and SPORTDiscus). Eligibility criteria for selecting studies: Inclusion was restricted to investigations that assessed exercise performance (time trials (TTs), sprint and intermittent exercise tests) and capacity (time to exhaustion test, TTE) with acute hypoxic (<24 h) exposure and a normoxic comparator. RESULTS Eighty-two outcomes from 53 studies (N = 798) were included in this review. The results show an overall reduction in exercise performance/capacity -17.8 ± 3.9% (95% CI -22.8% to -11.0%), which was significantly moderated by -6.5 ± 0.9% per 1000 m altitude elevation (95% CI -8.2% to -4.8%) and oxygen saturation (-2.0 ± 0.4%; 95% CI -2.9% to -1.2%). TT (-16.2 ± 4.3%; 95% CI -22.9% to -9%) and TTE (-44.5 ± 6.9%; 95% CI -51.3% to -36.7%) elicited a negative effect, whilst indicating a quadratic relationship between hypoxic magnitude and both TTE and TT performance. Furthermore, exercise less than 2 min exhibited no ergolytic effect from acute hypoxia. Summary/Conclusion: This review highlights the ergolytic effect of acute hypoxic exposure, which is curvilinear for TTE and TT performance with increasing hypoxic levels, but short duration intermittent and sprint exercise seem to be unaffected.
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Affiliation(s)
- Sanjoy K Deb
- a Sports Nutriton and Performance Research Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Daniel R Brown
- a Sports Nutriton and Performance Research Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Lewis A Gough
- a Sports Nutriton and Performance Research Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | | | - Paul A Swinton
- c School of Health Sciences , Robert Gordon University , Aberdeen , UK
| | - S Andy Sparks
- a Sports Nutriton and Performance Research Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Lars R Mcnaughton
- a Sports Nutriton and Performance Research Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK.,d Department of Sport and Movement Studies, Faculty of Health Science , University of Johannesburg , Johannesburg , South Africa
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Gough LA, Deb SK, Sparks SA, McNaughton LR. Sodium bicarbonate improves 4 km time trial cycling performance when individualised to time to peak blood bicarbonate in trained male cyclists. J Sports Sci 2017; 36:1705-1712. [PMID: 29183257 DOI: 10.1080/02640414.2017.1410875] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of this study was to investigate the effects of sodium bicarbonate (NaHCO3) on 4 km cycling time trial (TT) performance when individualised to a predetermined time to peak blood bicarbonate (HCO3-). Eleven male trained cyclists volunteered for this study (height 1.82 ± 0.80 m, body mass (BM) 86.4 ± 12.9 kg, age 32 ± 9 years, peak power output (PPO) 382 ± 22 W). Two trials were initially conducted to identify time to peak HCO3- following both 0.2 g.kg-1 BM (SBC2) and 0.3 g.kg-1 BM (SBC3) NaHCO3. Thereafter, on three separate occasions using a randomised, double-blind, crossover design, participants completed a 4 km TT following ingestion of either SBC2, SBC3, or a taste-matched placebo (PLA) containing 0.07 g.kg-1 BM sodium chloride (NaCl) at the predetermined individual time to peak HCO3-. Both SBC2 (-8.3 ± 3.5 s; p < 0.001, d = 0.64) and SBC3 (-8.6 ± 5.4 s; p = 0.003, d = 0.66) reduced the time to complete the 4 km TT, with no difference between SBC conditions (mean difference = 0.2 ± 0.2 s; p = 0.87, d = 0.02). These findings suggest trained cyclists may benefit from individualising NaHCO3 ingestion to time to peak HCO3- to enhance 4 km TT performance.
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Affiliation(s)
- Lewis A Gough
- a Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Sanjoy K Deb
- a Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - S Andy Sparks
- a Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Lars R McNaughton
- a Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK.,b Department of Sport and Movement Studies, Faculty of Health Science , University of Johannesburg , Johannesburg , South Africa
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26
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Gough LA, Deb SK, Sparks A, McNaughton LR. The Reproducibility of 4-km Time Trial (TT) Performance Following Individualised Sodium Bicarbonate Supplementation: a Randomised Controlled Trial in Trained Cyclists. SPORTS MEDICINE - OPEN 2017; 3:34. [PMID: 28936625 PMCID: PMC5608656 DOI: 10.1186/s40798-017-0101-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/01/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND Individual time to peak blood bicarbonate (HCO3-) has demonstrated good to excellent reproducibility following ingestion of both 0.2 g kg-1 body mass (BM) and 0.3 g kg-1 BM sodium bicarbonate (NaHCO3), but the consistency of the time trial (TT) performance response using such an individualised NaHCO3 ingestion strategy remains unknown. This study therefore evaluated the reproducibility of 4-km TT performance following NaHCO3 ingestion individualised to time to peak blood bicarbonate. METHODS Eleven trained male cyclists completed five randomised treatments with prior ingestion of 0.2 g kg-1 (SBC2) or 0.3 g kg-1 BM (SBC3) NaHCO3, on two separate occasions each, or a control trial entailing no supplementation. Participants completed a 4-km cycling TT on a Velotron ergometer where time to complete, power and speed were measured, whilst acid-base blood parameters were also recorded (pH and blood bicarbonate concentration HCO3-) and lactate [La-]. RESULTS Alkalosis was achieved prior to exercise in both SBC2 and SBC3, as pH and HCO3- were greater compared to baseline (p < 0.001), with no differences between treatments (p > 0.05). The reproducibility of the mean absolute change from baseline to peak in HCO3- was good in SBC2 (r = 0.68) and excellent in SBC3 (r = 0.78). The performance responses following both SBC2 and SBC3 displayed excellent reproducibility (r range = 0.97 to 0.99). CONCLUSIONS Results demonstrate excellent reproducibility of exercise performance following individualised NaHCO3 ingestion, which is due to the high reproducibility of blood acid-base variables with repeat administration of NaHCO3. Using a time to peak HCO3- strategy seems to cause no dose-dependent effects on performance for exercise of this duration and intensity; therefore, athletes may consider smaller doses of NaHCO3 to mitigate gastrointestinal (GI) discomfort.
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Affiliation(s)
- Lewis Anthony Gough
- Sports Nutrition and Performance Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire L39 4QP UK
| | - Sanjoy Kumar Deb
- Sports Nutrition and Performance Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire L39 4QP UK
| | - Andy Sparks
- Sports Nutrition and Performance Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire L39 4QP UK
| | - Lars Robert McNaughton
- Sports Nutrition and Performance Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire L39 4QP UK
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