Buffers. Technical Document

Transcription

1 Buffers Technical Document Developed by INDI/SNIG for the Irish Sports Council 2009

2 Table of Contents Introduction - Bicarbonate 3 Proposed benefits of bicarbonate loading among athletes 3 Appropriate situations for bicarbonate use 3 Recommended dosage 3 Concerns with bicarbonate use 4 4 Introduction - Beta Alanine (β-alanine) 6 Proposed benefits of β-alanine use among athletes 7 Appropriate situations for β-alanine use 7 Recommended dosage of β-alanine 7 Concerns with β-alanine use 7 7 Notes 9 References 10 2

3 Introduction Bicarbonate Bicarbonate is one of the body s natural buffering agents. Natural stores of bicarbonate in the body are relatively small and research has identified that introducing additional bicarbonate (usually as the sodium salt, but the potassium salt would likely be equally effective) into the body before exercise can cause a shift of lactate and hydrogen ions out of the muscle cell in some athletes (Kolkhorst et al. 2004, Renfree 2007, Zoladz et al. 2005, Robergs et al. 2005). Lactate and hydrogen ions are by-products of high intensity exercise, and as a result, research on bicarbonate ingestion has been carried out in sports that involve anaerobic metabolism such as high intensity swimming, cycling, rowing and running, and intermittent individual and team sports (Lindh et al. 2008, Pruscino et al. 2008, Zajac et al. 2009, Kolkhorst et al. 2004, Matsuura et al. 2007, Zoladz et al. 2005, Robergs et al. 2005, Van Montfoort et al. 2004, Artiolo et al. 2007, Bishop and Claudius 2005). The purported benefit from sodium bicarbonate ingestion before exercise is to increase in the ph and bicarbonate concentrations in blood, therefore modifying the blood acid-base balance. Sodium bicarbonate s exact mechanisms of action have not been demonstrated conclusively, and there appears to be substantial variation between individuals as to the impact sodium bicarbonate may have on performance (Requena et al. 2005). Since the early 1980 s research into the use of sodium bicarbonate as an ergogenic aid has steadily increased, with the majority of the research lending itself to performance benefits, but there are still many studies failing to demonstrate any positive performance outcomes in athletic populations after sodium bicarbonate ingestion. Proposed benefits of bicarbonate loading among athletes It is proposed that sodium bicarbonate loading can delay the onset of muscle fatigue in events of a short duration at a high (near maximal) intensity. Research has demonstrated performance benefits from sodium bicarbonate loading in events lasting from 30 seconds-7 minutes (Van Montfoort et al. 2004, Edge et al. 2006, Douroudos et al. 2006, Lindh et al. 2008, Pruscino et al. 2008, Zajac et al. 2009) along with intermittent sports (Artiolo et al. 2007, Bishop and Claudius 2005). The consumption of sodium bicarbonate when carried out correctly may buffer excess hydrogen ions and provide the ergogenic effects of reducing metabolic acidosis and the degree of impaired muscle oxidative capacity (Burke and Pyne 2007, Kolkhorst et al. 2004, Renfree 2007, Zoladz et al. 2005, Robergs et al. 2005). This may assist with maintaining power output and delaying fatigue. Appropriate situations for bicarbonate use Sodium bicarbonate loading has demonstrated ergogenic effects in events that are performed near maximal intensity from 30 seconds-7 minutes (see Table 1). The timing of sodium bicarbonate ingestion varies from study to study, with sodium bicarbonate ingested in some studies from 60 minutes prior to an event (Bishop and Claudius 2005, Robergs et al. 2005) up to 6 days before an event (McNaughton et al 1997, McNaughton et al. 1999). The optimal timing of bicarbonate ingestion in relation to the start of exercise would appear to be between 90 and 60 minutes beforehand, with bicarbonate being ingested over a 30 minute period or longer to prevent any gastrointestinal disturbances. Recommended dosage There is slight variation among the literature, but the majority of the research involves an acute loading protocol of 0.3 g sodium bicarbonate per kg body mass. This dosage is usually split into multiple doses consumed over a minute period, minutes before the event. The Australian Institute of Sport recommend two protocols for the consumption of bicarbonate to assist with performance enhancement (AIS Nutrition Department). Acute loading g sodium bicarbonate per kg body mass min before training or competition. Chronic loading g sodium bicarbonate per kg body mass, split into four doses spread over the day, consumed for 5-6 consecutive days. 3

4 The ingestion of bicarbonate should always be accompanied by water. The volumes have varied significantly from ad lib (Lindh et al. 2008) up to in excess of 2 L (Matsuura et al. 2007). The average fluid consumption from the research in Table 1 is 1.08L. Concerns with bicarbonate use Any potential performance enhancements appear to be highly individual and must be balanced by the risk with several potent side affects associated with the ingestion of sodium bicarbonate supplementation being reported. Despite this, the majority of studies note minimal side effects after ingestion of sodium bicarbonate, but diarrhoea, nausea, bloating, and vomiting have all been reported as side effects from sodium bicarbonate ingestion (Kolkhorst et al. 2004). These usually occur as a consequence of rapid ingestion or of ingestion of bicarbonate in solution. These problems can be reduced or avoided if bicarbonate is ingested in the form of tablets or gelatine capsules. Table 1. of Bicarbonate literature Reference Subjects Dose Sport / Exercise Protocol Performance Enhancement Artiolo et al experienced Judo competitors 0.3 g/kg of either Sodium Bicarbonate (SB) or placebo as a gelatinous capsule, 120 min before the beginning of two separate trials. Judo - 4 bouts of the Wingate test for upper limbs and a specific judo fitness test. SB ingestion had an ergogenic effect on high-intensity, short -term, intermittent performance. Kolkhorst et al males and 1 female 0.3 g/kg body weight of SB dissolved in 1 L of water or water only. Each subject completed one 6-min cycling bout at a power output predicted to correspond to 25 W greater than power output at V T on 2 separate occasions Not assessed Bicarbonate ingestion diminished fatigue in working fibers during the slow component Matsuura et al healthy males 0.3 g/kg of SB or CaCO3 consumed in 6 parts, each part ingested with 350 ml of water at intervals of 10 min 3 hours prior to the exercise protocol. Repeated sprint cycling performed with a resistive load of BM Blood lactate, oxygen uptake and surface EMG (electromyography) assessed. No SB did not affect surface EMG during repeated cycling sprints. It is possible that performance during repeated cycling sprints is affected by both peripheral factors and muscle recruitment strategy. Renfree male and 3 females 0.3g/kg SB or CaCO 3 in 400 ml of plain water in 3 equal doses taken at 0, 15, and 30 minutes. No exercise protocol was carried out only plasma H + levels post SB ingestion studied. Not assessed Plasma H + was lower after SB than CaCO 3 at all points after ingestion. Therefore CaCO 3 can be used as placebo. Van Montfoort et al competitive male endurance runners SB was consumed as gelatin capsules equivalent to 300 mg/kg (20-60 capsules) plus 750 ml of water over 90 mins. Running to exhaustion after ingestion of SB with sodium citrate, sodium lactate and a placebo (sodium chloride). SB is possibly more beneficial to sprint performance than lactate and probably more beneficial than citrate or chloride 4

5 Table 1. of Bicarbonate literature, cont d. Reference Subjects Dose Sport / Exercise Protocol Performance Enhancement Zoladz et al healthy physically active men 250 mg/kg of SB with up to 500 ml of water. When significant alkalemia had occurred, approx 90 min after ingestion the subjects performed the constant -power-output test. An incremental cycling test then 2 constant-poweroutput test (each of 6-min duration, one at 40% VO 2 and the second at 80% VO 2 ). Blood samples and Pulmonary V O2 were measured. Not assessed Pre-exercise metabolic alkalosis, induced by SB ingestion caused a significant acceleration of the primary component of V02 kinetics at the onset of a high-poweroutput exercise. Bishop and Claudius female team -sport athletes Two doses of either 0.2g/kg of SB or 0.138g/kg of NaCl (placebo) 90 and 20 min before exercise. The protocol was designed to simulate a team based sport and was divided into ~2-min blocks of sprinting, active recovery, and passive rest. The results of this study suggest that SB ingestion can improve intermittent-sprint performance and may be a useful supplement for teamsport athletes Lindh et al elite male swimmers 300mg/kg body mass as gelatine capsules consumed over a 30min period commencing 90min prior to the start of the performance, with water taken ad libitum One 200m freestyle maximal effort swim after a 10 min warm -up. Blood lactate and performance were the primary outcome measures. It was concluded that SB supplementation can improve 200m freestyle performance, most likely by increasing buffering capacity. Pruscino et al elite male freestyle swimmers SB (0.3g/kg B), caffeine (6.2 ± 0.3g/kg ; C), a combination of both (B+C), and placebo (P) was ingested in 7 intervals over 90 minutes 2 hours prior to the swim. Two maximal 200-m freestyle time trials separated by 30 min on 4 separate occasions. SB and SB+C produced faster swim times when compared to C alone. Robergs et al trained male cyclists 0.3g/kg of SB (ACD), 0.2g/kg of Na+HCO3- and 0.2 g/kg of sodium citrate (ALK), or a placebo as capsules over 10 minutes with water 60 min before exercise. Intense cycle exercise at 80 rpm and power output equivalent to 110% workload at VO2max. This intensity was designed to cause volitional fatigue after 2 to 3 No Induced alkalosis decreases metabolic acidosis and improves ph recovery compared to acidodic and placebo conditions. 5

6 Table 1. of Bicarbonate literature, cont d. Reference Subjects Dose Sport / Exercise Protocol Performance Enhancement Zajac et al well trained competitive youth male swimmers 500 ml solution containing SB (300 mg/ kg) or placebo consumed over 15 min 90 min prior to the trial. Two test trials consisting of 4 x 50 m freestyle with a 1 min passive rest interval between each sprint. Blood lactate and swim time were the primary outcome measures. Ingestion of SB in young athletes is an effective buffer during high intensity interval swimming at distances from 50 to 200 m. Edge et al moderately trained females SB or placebo ingestion of 0.2 g/kg per day at 90 and 30 min before performing each training session 3 intensive interval training sessions per week for 8 weeks on a cycle ergometer. The group ingesting SB had greater improvements in lactate threshold and endurance performance, possibly because of a reduced metabolicacidosis during training and a greater improvement in muscle oxidative capacity. Douroudos et al healthy males Either moderate SB intake (0.3g/kg per day), high SB intake (0.5 g/kg per day) placebo for 5 consecutive days split over 2 doses. Wingate test on cycle ergometer performed before and after supplementation. SB ingestion for 5 days may prevent acid-base balance disturbances and improve performance during anaerobic exercise in a dosedependent manner. Beta Alanine (β-alanine) Introduction Carnosine is a natural buffer that is present inside muscle fibres. Carnosine is a dipeptide composed of two amino acids, β-alanine and L-histidine, and is found in skeletal muscle and cells of the central nervous system (Harris et al. 2006, Kendrick et al. 2008, Smith et al. 2009). The physiological role of carnosine is ph buffering inside the muscle fibre and it has been shown to enhance the buffering capacity during high-intensity exercise lasting 1-2 minutes. Type 2 muscle fibres typically containing a higher concentration of carnosine (Harris et al. 2006). Research has demonstrated that increasing muscle carnosine stores can increase the buffering capacity inside the muscles during exercise and therefore may enhance performance (Derave et al. 2007, Kendrick et al. 2009). There is an abundance of L-histidine in the muscle and β-alanine has been suggested as the limiting factor to carnosine production. Research has demonstrated that through β-alanine supplementation and training, the carnosine content in a muscle can be increased, hence increasing the buffering of hydrogen ions in the muscle (Harris et al 2006, Derave et al. 2007, Kendrick et al. 2009). β-alanine can be purchased as capsules or powder, most commonly as a powder in conjunction with other supplements such as creatine. 6

7 Proposed benefits of β-alanine use among athletes β-alanine consumption has demonstrated performance benefits in high intensity exercise lasting 1-2 minutes in many studies (Smith et al. 2009, Derave et al. 2007, Hill et al. 2007, Hoffman et al. 2008, Stout et al. 2007) and also in endurance exercise (Van Thienen et al. 2009). See Table 2 for a summary of the literature. As hydrogen ions accumulate during anaerobic exercise, the ability of the muscle fibre to contract and produce force decreases (Fitts and Holloszy (1976) cited in Stout et al 2007). Through neutralising the hydrogen ions, time to fatigue during high intensity exercise may be enhanced (Stout et al. 2007, Derave et al. 2007), an increase total work observed (Hill et al. 2007), and enhance muscular endurance demonstrated (Hoffman et al. 2008). Appropriate situations for β-alanine use The majority of positive research into the possible benefits of β-alanine has been conducted in weight lifters and cyclists. Based on research to date, it is feasible to suggest β-alanine ingestion for ergogenic benefits could be extrapolated to any sport that is of high intensity and short duration, for example intermittent team sports, court sports, swimming, running and cycling, though further research is required to confirm this. Recommended dosage of β-alanine There are currently no recognised dosages guidelines for β-alanine consumption. Studies have demonstrated beneficial outcomes with doses ranging from g per day over a 4-10 week period, see Table 2. Concerns with β-alanine use An increasing amount of research into β-alanine and sporting performance has emerged this year. The majority of studies have reported no acute side effects with the exception of a possible tingling sensation on the skin (paraesthesia) (Harris et al. 2006). Due to the limited and recent research, possible long term side effects are currently unknown. Table 2. of β-alanine literature Reference Subjects Dose Sport / Exercise Hoffman et al Kendrick et al collegiate football players 26 sports science students 4.5 g of Beta Alanine (BA) per day for 30 days or placebo 6.4 g per day of BA or placebo for 10 weeks Protocol Pre-season training was the intervention with the performance measures being 60-second Wingate anaerobic power test and 3 line drills Resistance training. Outcome measures assessed were whole body strength, isokinetic force production, muscular endurance, body composition Performance Enhancement No No Despite positive trends, BA did not result in significant improvements in fatigue rates during high-intensity anaerobic exercise. There was no significant effect of BA supplementation on any of the exercise parameters measured, mass or % body fat. 7

8 Table 2. of β-alanine literature, cont d. Reference Subjects Dose Sport / Exercise Smith et al Derave et al Hill et al recreationally active males. 15 well trained male track-andfield athletes 13 male subjects 6g per day for 42 days 4 5 weeks of BA (2.4 g/day during the first 4 days, 3.6 g/day during the subsequent 4 days, and from then on 4.8 g/day until the end of the study) or a placebo. 4 or 10 weeks of BA or placebo. BA dose was 4g/day in week 1, 4.8g/day in week 2, 5.6g/day in week 3 then 6.4g/day week 4. Subjects who supplemented for 10 weeks consumed 6.4g/day in weeks Protocol Six weeks of high intensity interval training consisting of 5 6 bouts of a 2:1 minute cycling work to rest ratio Subjects completed their normal training regime of 5-6 training sessions per week which involved power, speed, resistance, and endurance training. Cycle capacity tests at 110% of maximum power output were completed at baseline then at week 4 of supplementation and 4 weeks post, and week 10 and 10 weeks post for those subjects with extended supplementation. Performance Enhancement Chronic BA supplementation may further enhance high intensity interval training, improved endurance performance and lean body mass. The main findings were: muscle carnosine increased; carnosine loading significantly attenuated fatigue in repeated bouts of exhaustive dynamic contractions, however BA supplementation did not improve isometric endurance or 400-m race time. 4 wks BA supplementation resulted in a significant increase in total work completed (assessed on cycle ergometer) with a further increase at 10 week time point. Hoffman et al experienced resistancetrained men 4.8g of BA or placebo per day for 30 days. Acute resistance exercise protocol consisting of 6 sets of 12 repetitions of the squat exercise at 70% of 1RM with 90 sec rest between sets. Four weeks of BA supplementation can significantly improve muscular endurance during resistance training. Kendrick et al male students 6.4g per day for 4 weeks. 4 weeks of isokinetic training with the right leg whilst the left leg was untrained. Not assessed Increase in carnosine content was seen with BA supplementation in both the trained and untrained legs. Training did not further increase carnosine content in the trained leg. Smith et al recreationally active men 6g of BA or placebo per day for 3 weeks. 6 weeks of highintensity interval training consisting of 2-min intervals with 1-min rest between bouts on a cycle ergometer. No BA had no significant influence on electromyographic fatigue threshold or efficiency of electrical activity. The training protocol may have been a superior stimulus in untrained men, minimizing any effect of increased carnosine levels. 8

9 Table 2. of β-alanine literature, cont d. Reference Subjects Dose Sport / Exercise Stout et al Van Thienen et al females BA 3.2 g per day for days 1 7, and 6.4 g per day for days 8 28 or placebo. 21 moderately to welltrained male cyclists BA supplemented 2 g per day (weeks 1 and 2), 3g per day (weeks 3 and 4) and 4 g per day from week 5 to the end of the study or placebo Protocol Ventilatory threshold, physical working capacity, fatigue threshold and time to exhaustion were all assessed before and after supplementation on a cycle ergometer. 110-min simulated cycling race before and after supplementation Performance Enhancement BA supplementation delayed the onset of neuromuscular fatigue and ventilatory threshold, leading to increases in sub-maximal performance and time to exhaustion. BA supplementation can significantly enhance sprint performance at the end of an exhaustive endurance exercise bout. Notes Pubmed (Medline) and SPORTDiscus were searched for all human studies published in peer reviewed journals in the last 5 years. The terms searched for bicarbonate were: sodium bicarbonate, bicarbonate, sodium bicarbonate AND exercise and bicarbonate AND exercise, and the search terms for beta-alanine were beta-alanine and beta alanine AND exercise were used as key terms in all databases. The reference list from the bicarbonate and beta-alanine articles retrieved were then searched for any additional land mark papers. Carnosine was an additional key term searched. Inclusion criteria Human studies published in English Healthy subjects Original investigations assessing the use of bicarbonate and exercise and beta alanine and exercise Incorporated the use of an indistinguishable placebo Exclusion Criteria Studies assessing bicarbonate or beta alanine in a combination with another supplement i.e. Creatine Qualitative studies assessing supplement use in both the general and athletic population After title and abstract review, 13 original articles that assessed the use of bicarbonate in exercise settings and 10 which assessed beta-alanine in an exercise setting were retrieved for review. 9

10 References Artiolo GG, Gualano B, Coelho DF, Benatti FB, Gailey AW, Lancha AH. Does Sodium-Bicarbonate Ingestion Improve Simulated Judo Performance? Int J Sport Nutr Exerc Metab 2007, 17, Australian Institute of Sport. (2009). Bicarbonate and Citrate. Available: supplements/supplement_fact_sheets/group_a_supplements/bicarbonate. Last accessed 5th September Bishop D and Claudius B. Effects of Induced Metabolic Alkalosis on Prolonged Intermittent-Sprint Performance. Med Sci Sports Exerc. 37 (5), May Burke LM, Pyne DB. Bicarbonate loading to enhance training and competitive performance. Int J Sports Physiol Perform Mar;2(1):93-7. Derave W, Ozdemir MS, Harris RC, Pottier A, Reyngoudt H, Koppo K, Wise JA, Achten E. β-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters. J Appl Physiol 103: , Douroudos II, Fatouros IG, Gourgoulis V, et al. Dose-related effects of prolonged NaHCO3 ingestion during highintensity exercise. Med Sci Sports Exerc. 2006;38: Edge J, Bishop D, Goodman C. Effects of chronic NaHCO3 ingestion during interval training on changes to muscle buffer capacity, metabolism and short-term endurance performance. J Appl Physiol. 2006;101: Harris RC, Tallon MJ, Dunnett M, Boobis L, Coakley J, Kim HJ, Fallowfield JL, Hill CA, Sale C, Wise JA. The absorption of orally supplied β-alanine and its effect on muscle carnosine synthesis in humans vastus lateralis. Amino Acids (2006) 30: Hill CA, Harris RC, Kim HJ, Harris BD, Sale C, Boobis LH, Kim CK, Wise JA. Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity. Amino Acids Feb;32(2): Hoffman JR, Ratamess NA, Faigenbaum AD, Ross R, Kang J, Stout JR, Wise JA. Short-duration beta-alanine supplementation increases training volume and reduces subjective feelings of fatigue in college football players. Nutr Res Jan;28(1):

11 Kendrick IP, Kim HJ, Harris RC, Kim CK, Dang VH, Lam TQ, Bui TT, Wise JA. The effect of 4 weeks beta-alanine supplementation and isokinetic training on carnosine concentrations in type I and II human skeletal muscle fibres. Eur J Appl Physiol May;106(1): Kendrick IP, Harris RC, Kim HJ, Kim CK, Dang VH, Lam TQ, Bui TT, Smith M, Wise JA. The effects of 10 weeks of resistance training combined with beta-alanine supplementation on whole body strength, force production, muscular endurance and body composition. Amino Acids May;34(4): Kolkhorst FW, Rezende RS, Levy SS, Buono MJ. Effects of sodium bicarbonate on VO2 kinetics during heavy exercise. Med Sci Sports Exerc Nov;36(11): Lindh AM, Peyrebrune MC, Ingham SA, Bailey DM, Folland JP. Sodium bicarbonate improves swimming performance. Int J Sports Med Jun;29(6): Matsuura R, Arimitsu T, Kimura T, Yunoki T, Yano T. Effect of oral administration of sodium bicarbonate on surface EMG activity during repeated cycling sprints. Eur J Appl Physiol Nov;101(4): McNaughton LR, Siegler J, Midgley A. Ergogenic effects of sodium bicarbonate. Curr Sports Med Rep Jul-Aug;7 (4): McNaughton L, Backx K, Palmer G, Strange N. Effects of chronic bicarbonate ingestion of the performance of highintensity work. Eur J Appl Physiol. 1999;80: McNaughton LR, Ford S, Newbold C. Effects of sodium bicarbonate ingestion on high intensity exercise in moderately trained women. J Strength Cond Res. 1997;11: Pruscino CL, Ross ML, Gregory JR, Savage B, Flanagan TR. Effects of sodium bicarbonate, caffeine, and their combination on repeated 200-m freestyle performance. Int J Sport Nutr Exerc Metab Apr;18(2): Renfree A. The time course for changes in plasma [h+] after sodium bicarbonate ingestion. Int J Sports Physiol Perform Sep;2(3): Robergs R, Hutchinson K, Hendee S, Madden S, Siegler J. Influence of pre-exercise acidosis and alkalosis on the kinetics of acid-base recovery following intense exercise. Int J Sport Nutr Exerc Metab Feb;15(1): Requena B, Zabala M, Padial P, Feriche B. Sodium bicarbonate and sodium citrate: ergogenic aids? J Strength Cond Res Feb;19(1):

12 Van Montfoort MCE, Van Dieren L, Hopkins WG, Shearman JP. Effects of Ingestion of Bicarbonate, Citrate, Lactate, and Chloride on Sprint Running. Med Sci Sports Exerc. 26 (7): , July Zajac A, Cholewa J, Poprzecki S, Waskiewicz Z, Langfort J. Effects of sodium bicarbonate ingestion on swim performance in youth athletes. J of Sport Sci and Med (2009) 8, Zoladz JA, Szkutnik Z, Duda K, Majerczak J, Korzeniewski B. Preexercise metabolic alkalosis induced via bicarbonate ingestion accelerates Vo2 kinetics at the onset of a high-power-output exercise in humans. J Appl Physiol Mar;98(3):