The Reproducibility of Blood Acid Base Responses in Male Collegiate Athletes Following Individualised Doses of Sodium Bicarbonate: A Randomised Controlled Crossover Study

The blood acid base and gastrointestinal response to three different forms of sodium citrate encapsulation

Enterically coated (ENT) or delayed-release (DEL) capsules may lessen gastrointestinal symptoms (GIS) following acute sodium citrate (SC) ingestion, although the effects on blood acid-base balance are undetermined. Fourteen active males ingested 0.4 g.kg-1 body mass (BM) SC, within gelatine (GEL), DEL and ENT capsules or 0.07 g.kg-1 BM sodium chloride control (CON). Blood acid-base balance and GIS were measured for 4 h. Ingestion form had no significant effect on total GIS experienced (GEL: 2 ± 7; DEL: 1 ± 8; ENT: 1 ± 4 AU). Most (7/14) participants experienced zero symptoms throughout. Peak GIS typically emerged ≤100 min post-ingestion, with a similar time to reach peak GIS between ingestion form (GEL: 36 ± 70; DEL: 13 ± 28; ENT: 15 ± 33 AU). Blood [HCO3-] was significantly higher with ENT versus GEL (ENT: 29.0 ± 0.8; GEL: 28.5 ± 1.1 mmol.L-1, P = 0.037). Acute ingestion of a reduced SC dose elicited minimal GIS, producing significant changes in blood [HCO3-] from rest, irrespective of ingestion form (GEL: 6.0 ± 0.9; DEL: 5.1 ± 1.0; ENT: 6.2 ± 0.8 mmol.L-1). The necessity of individualized ingestion strategies is also challenged, with sustained increases in blood [HCO3-] of ≥4 mmol.L-1 for up to 153 min highlighted. If commencing exercise at peak alkalosis augments subsequent performance above starting at a standardized time point where HCO3- is still elevated remains unclear.

Enhancing exercise performance and recovery through sodium bicarbonate supplementation: introducing the ingestion recovery framework

Sodium bicarbonate (SB) supplementation is an ergogenic strategy for athletes competing in high-intensity exercise, but the efficacy of SB for accelerating recovery from exercise and thus improving performance during repeated bouts of exercise is not fully understood. In a similar fashion to using SB as a pre-exercise buffer, it is possible accelerated restoration of blood pH and bicarbonate following an exercise bout mechanistically underpins the use of SB as a recovery aid. Physiological mechanisms contributing to beneficial effects for SB during repeated bout exercise could be more far-reaching however, as alterations in strong ion difference (SID) and attenuated cellular stress response might also contribute to accelerated recovery from exercise. From inspection of existing literature, ingestion of 0.3 g kg-1 body mass SB ~60-90 min pre-exercise seems to be the most common dosage strategy, but there is evidence emerging for the potential application of post-exercise supplementation timing, gradual SB doses throughout a competition day, or even ingestion during exercise. Based on this review of literature, an SB ingestion recovery framework is proposed to guide athletes and practitioners on the use of SB to enhance performance for multiple bouts of exercise.

The Effects of a Novel Sodium Bicarbonate Ingestion System on Repeated 4 km Cycling Time Trial Performance in Well-Trained Male Cyclists

BACKGROUND

A novel sodium bicarbonate (SB) product has come to market named the "Bicarb System" (M-SB; Maurten AB, Gothenburg, Sweden). It claims to minimise gastrointestinal (GI) discomfort whilst still improving exercise performance.

AIM

To investigate the effects of M-SB ingestion on repeated 4 km cycling time trials (TT1 and TT2) in well-trained male cyclists.

METHODS

The study recruited ten well-trained cyclists (maximal oxygen uptake (V ˙ O 2 max ): 67 ± 4 ml kg-1 min-1 BM; peak power output (PPO) atV ˙ O 2 max : 423 ± 21 W) to take part in this randomised, crossover and double-blinded study. Following one visit to determineV ˙ O 2 max , participants completed a second visit to identify individual time to peak blood bicarbonate (HCO3-) (ITTP) in a rested state. Visit three was a familiarisation trial mimicking the experimental procedures. Visits four to seven consisted of completing 2 × 4 km cycling TTs separated by 45 min passive recovery, following one of either: 0.3 g kg-1 BM M-SB, 0.21 g kg-1 BM sodium chloride (placebo; PLA) in vegetarian capsules (size 00), or a control trial (CON). Supplements (M-SB or placebo) were ingested pre-exercise at their respective ITTP.

RESULTS

Performance in TT1 was faster in the M-SB condition compared with TT1 in CON (- 5.1 s; p = 0.004) and PLA (- 3.5 s; p < 0.001). In TT2, performance was also significantly faster in the M-SB condition compared with CON (- 4.4 s; p = 0.018) or PLA (- 4.1 s; p = 0.002). Total aggregated GI symptoms were generally low and not significantly different between PLA and the M-SB conditions for a range of symptoms.

CONCLUSIONS

The ingestion of M-SB improves repeated 4 km cycling TT performance and the recovery of acid-base balance between bouts, whilst causing minimal GI discomfort.

The effect of sodium bicarbonate mini-tablets ingested in a carbohydrate hydrogel system on 40 km cycling time trial performance and metabolism in trained male cyclists

INTRODUCTION

Sodium bicarbonate (NaHCO3) ingestion has been found to be ergogenic in high-intensity exercise that ranges from 1 to 10 min; however, limited studies have investigated high-intensity exercise beyond this duration.

PURPOSE

The present study aimed to determine the effect of NaHCO3 ingested using a carbohydrate hydrogel delivery system on 40 km time trial (TT) performance in trained male cyclists.

METHODS

Fourteen trained male cyclists ingested 0.3 g kg-1 BM NaHCO3 (Maurten AB, Sweden) to determine individualised peak alkalosis, which established time of ingestion prior to exercise. Participants completed a 40 km familiarisation TT, and two 40 km experimental TTs after ingestion of either NaHCO3 or placebo in a randomised, double-blind, crossover design.

RESULTS

NaHCO3 supplementation improved performance (mean improvement = 54.14 s ± 18.16 s; p = 0.002, g = 0.22) and increased blood buffering capacity prior to (HCO3- mean increase = 5.6 ± 0.2 mmol L-1, p < 0.001) and throughout exercise (f = 84.82, p < 0.001, pη2 = 0.87) compared to placebo. There were no differences in total gastrointestinal symptoms (GIS) between conditions either pre- (NaHCO3, 22 AU; Placebo, 44 AU; p = 0.088, r = 0.46) or post-exercise (NaHCO3, 76 AU; Placebo, 63 AU; p = 0.606, r = 0.14).

CONCLUSION

The present study suggests that ingesting NaHCO3 mini-tablets in a carbohydrate hydrogel can enhance 40 km TT performance in trained male cyclists, with minimal GIS. This ingestion strategy could therefore be considered by cyclists looking for a performance enhancing ergogenic aid.

The Effects of a Carbohydrate Hydrogel System for the Delivery of Bicarbonate Mini-Tablets on Acid-Base Buffering and Gastrointestinal Symptoms in Resting Well-trained Male Cyclists

BACKGROUND

A new commercially available sodium bicarbonate (SB) supplement claims to limit gastrointestinal (GI) discomfort and increase extracellular buffering capacity. To date, no available data exists to substantiate such claims. Therefore, the aim of this study was to measure blood acid-base balance and GI discomfort responses following the ingestion of SB using the novel "Bicarb System" (M-SB). Twelve well-trained male cyclists completed this randomised crossover designed study. Maximal oxygen consumption was determined in visit one, whilst during visits two and three participants ingested 0.3 g∙kg-1 BM SB using M-SB (Maurten, Sweden) or vegetarian capsules (C-SB) in a randomised order. Finger prick capillary blood samples were measured every 30 min for pH, bicarbonate (HCO3-), and electrolytes (potassium, chloride, calcium, and sodium), for 300 min. Visual analogue scales (VAS) were used to assess GI symptoms using the same time intervals.

RESULTS

Peak HCO3- was 0.95 mmol∙L-1 greater following M-SB (p = 0.023, g = 0.61), with time to peak HCO3- achieved 38.2 min earlier (117 ± 37 vs. 156 ± 36 min; p = 0.026, r = 0.67) and remained elevated for longer (p = 0.043, g = 0.51). No differences were observed for any electrolytes between the conditions. Aggregated GI discomfort was reduced by 79 AU following M-SB (p < 0.001, g = 1.11), with M-SB reducing stomach cramps, bowel urgency, diarrhoea, belching, and stomach-ache compared to C-SB.

CONCLUSIONS

This is the first study to report that M-SB can increase buffering capacity and reduce GI discomfort. This presents a major potential benefit for athletes considering SB as an ergogenic supplement as GI discomfort is almost eliminated. Future research should determine if M-SB is performance enhancing.

The effects of sodium bicarbonate ingestion on swimming interval performance in trained competitive swimmers

The use of sodium bicarbonate (NaHCO3) supplementation to improve repeated high-intensity performance is recommended; however, most swimming performance studies examine time trial efforts rather than repeated swims with interspersed recovery that are more indicative of training sessions. The aim of this study, therefore, was to investigate the effects of 0.3 g.kg-1 BM NaHCO3 supplementation on sprint interval swimming (8 × 50 m) in regionally trained swimmers. Fourteen regionally competitive male swimmers (body mass (BM): 73 ± 8 kg) volunteered for this double-blind, randomised, crossover designed study. Each participant was asked to swim 8 × 50 m (front crawl) at a maximum intensity from a diving block, interspersed with 50 m active recovery swimming. After one familiarisation trial, this was repeated on two separate occasions whereby participants ingested either 0.3 g.kg-1 BM NaHCO3 or 0.05 g.kg-1 BM sodium chloride (placebo) in solution 60 min prior to exercise. Whilst there were no differences in time to complete between sprints 1-4 (p > 0.05), improvements were observed in sprint 5 (p = 0.011; ES = 0.26), 6 (p = 0.014; ES = 0.39), 7 (p = 0.005; ES = 0.60), and 8 (p = 0.004; ES = 0.79). Following NaHCO3 supplementation, pH was greater at 60 min (p < 0.001; ES = 3.09), whilst HCO3- was greater at 60 min (p < 0.001; ES = 3.23) and post-exercise (p = 0.016; ES = 0.53) compared to placebo. These findings suggest NaHCO3 supplementation can improve the latter stages of sprint interval swimming performance, which is likely due to the augmentation of pH and HCO3- prior to exercise and the subsequent increase in buffering capacity during exercise.

The interplay between bicarbonate kinetics and gastrointestinal upset on ergogenic potential after sodium bicarbonate intake: a randomized double-blind placebo-controlled trial

This double-blind placebo-controlled cross-over study utilized comprehensive monitoring of blood bicarbonate (HCO₃^¯) kinetics and evaluation of gastrointestinal (GI) upset to determine their impact on an ergogenic potential of sodium bicarbonate (SB) co-ingested with carbohydrate (CHO). Nineteen CrossFit athletes performed 6 bouts of 15 s Wingate Anaerobic Test (WAnT) 90 min post-ingestion of 0.4 g·kg^-1 body mass (BM) of SB (SB + CHO treatment) or PLA (PLA + CHO treatment) with 15 g CHO. Blood HCO₃^¯ concentration was evaluated at baseline, 30-, 60-, 75- and 90 min post-ingestion, in between WAnT bouts, and 3 and 45 min post-exercise, while GI upset at 120 min after protocol started. Control (no supplementation; CTRL) procedures were also performed. An effective elevation of extra-cellular buffering capacity was observed 60-90 min post-ingestion of SB + CHO. At mean peak blood HCO₃^¯, or at start of exercise an increase > 6 mmol·L^-1 in HCO₃^¯ was noted in 84% and 52.6% participants, respectively. SB + CHO did not prevent performance decrements in WAnT bouts. There were no significant relationships between changes in blood HCO₃^¯ and WAnTs' performance. Total GI was significantly higher in SB + CHO compared to CTRL, and stomach problems in SB + CHO compared to CTRL and PLA + CHO. There were inverse associations between peak- (p = 0.031; r = - 0.495), average- (p = 0.002; r = - 0.674) and minimum power (p = 0.008; r = - 0.585) and total GI upset, as well as average power and severe GI distress (p = 0.042; r = - 0.471) at SB + CHO. The implemented dose of SB + CHO was effective in improving buffering capacity, but did not prevent decrements in WAnTs' performance. GI side effects were crucial in affecting the ergogenic potential of SB and thus must be insightfully monitored in future studies.

The effects of enteric-coated sodium bicarbonate supplementation on 2 km rowing performance in female CrossFit® athletes

PURPOSE

Sodium bicarbonate (SB) supplementation can improve exercise performance, but few studies consider how effective it is in female athletes. The aim of the study was to establish the effect of individually timed pre-exercise SB ingestion on 2 km rowing time trial (TT) performance in female athletes.

METHODS

Eleven female CrossFit® athletes (mean ± SD age, 29 y ± 4 y, body mass, 64.5 kg ± 7.1 kg, height, 1.7 m ± 0.09 m, peak oxygen uptake [VO_2peak], 53.8 ± 5.7 mL·kg^-1∙min^-1). An initial trial identified individual time-to-peak [HCO₃^-] following enteric-coated 0.3 g·kg^-1 BM SB ingestion_. Participants then completed a 2 km TT familiarisation followed by a placebo (PLA) or SB trial, using a randomised cross-over design.

RESULTS

The ingestion of SB improved rowing performance (514.3 ± 44.6 s) compared to the PLA (529.9 ± 45.4 s) and FAM trials (522.2 ± 43.1 s) (p = 0.001, pη² = 0.53) which represents a 2.24% improvement compared to the PLA. Individual time-to-peak alkalosis occurred 102.3 ± 22.1 min after ingestion (range 75-150 min) and resulted in increased blood [HCO_3-] of 5.5 ± 1.5 mmol⋅L^-1 (range = 3.8-7.9 mmol⋅L^-1). The change in blood [HCO_3-] was significantly correlated with the performance improvement between PLA and SB trials (r = 0.68, p = 0.020).

CONCLUSIONS

Ingesting a 0.3 g·kg^-1 BM dose of enteric-coated SB improves 2 km rowing performance in female athletes. The improvement is directly related to the extracellular buffering capacity even when blood [HCO_3-] does not change ≥ 5.0 mmol⋅L^-1.

The effects of sodium bicarbonate supplementation at individual time-to-peak blood bicarbonate on 4-km cycling time trial performance in the heat

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.

Anthocyanin-Rich Supplementation: Emerging Evidence of Strong Potential for Sport and Exercise Nutrition

Dark-colored fruits, especially berries, have abundant presence of the polyphenol anthocyanin which have been show to provide health benefits. Studies with the berry blackcurrant have provided notable observations with application for athletes and physically active individuals. Alterations in exercise-induced substrate oxidation, exercise performance of repeated high-intensity running and cycling time-trial and cardiovascular function at rest and during exercise were observed with intake of New Zealand blackcurrant. The dynamic plasma bioavailability of the blackcurrant anthocyanins and the anthocyanin-derived metabolites must have changed cell function to provide meaningful in-vivo physiological effects. This perspective will reflect on the research studies for obtaining the applied in-vivo effects by intake of anthocyanin-rich supplementation, the issue of individual responses, and the emerging strong potential of anthocyanins for sport and exercise nutrition. Future work with repeated intake of known amount and type of anthocyanins, gut microbiota handling of anthocyanins, and coinciding measurements of plasma anthocyanin and anthocyanin-derived metabolites and in-vivo cell function will be required to inform our understanding for the unique potential of anthocyanins as a nutritional ergogenic aid for delivering meaningful effects for a wide range of athletes and physically active individuals.

Enteric-Coated Sodium Bicarbonate Attenuates Gastrointestinal Side-Effects

Enteric-formulated capsules can mitigate gastrointestinal (GI) side effects following sodium bicarbonate (NaHCO3) ingestion; however, it remains unclear how encapsulation alters postingestion symptoms and acid-base balance. The current study aimed to identify the optimal ingestion form to mitigate GI distress following NaHCO3 ingestion. Trained males (n = 14) ingested 300 mg/kg body mass of NaHCO3 in gelatin (GEL), delayed-release (DEL), and enteric-coated (ENT) capsules or a placebo in a randomized cross-over design. Blood bicarbonate anion concentration, potential hydrogen, and GI symptoms were measured pre- and postingestion for 3 hr. Fewer GI symptoms were reported with ENT NaHCO3 than with GEL (p = .012), but not with DEL (p = .106) in the postingestion phase. Symptom severity decreased with DEL (4.6 ± 2.8 arbitrary units) compared with GEL (7.0 ± 2.6 arbitrary units; p = .001) and was lower with ENT (2.8 ± 1.9 arbitrary units) compared with both GEL (p < .0005) and DEL (p = .044) NaHCO3. Blood bicarbonate anion concentration increased in all NaHCO3 conditions compared with the placebo (p < .0005), although this was lower with ENT than with GEL (p = .001) and DEL (p < .0005) NaHCO3. Changes in blood potential hydrogen were reduced with ENT compared with GEL (p = .047) and DEL (p = .047) NaHCO3, with no other differences between the conditions. Ingestion of ENT NaHCO3 attenuates GI disturbances for up to 3 hr postingestion. Therefore, ENT ingestion forms may be favorable for those who report GI disturbances with NaHCO3 supplementation or for those who have previously been deterred from its use altogether.

The time to peak blood bicarbonate (HCO3-), pH, and the strong ion difference (SID) following sodium bicarbonate (NaHCO3) ingestion in highly trained adolescent swimmers

The timing of sodium bicarbonate (NaHCO₃) supplementation has been suggested to be most optimal when coincided with a personal time that bicarbonate (HCO₃^–) or pH peaks in the blood following ingestion. However, the ergogenic mechanisms supporting this ingestion strategy are strongly contested. It is therefore plausible that NaHCO₃ may be ergogenic by causing beneficial shifts in the strong ion difference (SID), though the time course of this blood acid base balance variable is yet to be investigated. Twelve highly trained, adolescent swimmers (age: 15.9 ± 1.0 years, body mass: 65.3 ± 9.6 kg) consumed their typical pre-competition nutrition 1–3 hours before ingesting 0.3 g∙kg BM^-1 NaHCO₃ in gelatine capsules. Capillary blood samples were then taken during seated rest on nine occasions (0, 60, 75, 90, 105, 120, 135, 150, 165 min post-ingestion) to identify the time course changes in HCO₃^–, pH, and the SID. No significant differences were found in the time to peak of each blood measure (HCO₃^–: 130 ± 35 min, pH: 120 ± 38 min, SID: 98 ± 37 min; p = 0.08); however, a large effect size was calculated between time to peak HCO₃^– and the SID (g = 0.88). Considering that a difference between time to peak blood HCO₃^– and the SID was identified in adolescents, future research should compare the ergogenic effects of these two individualized NaHCO₃ ingestion strategies compared to a traditional, standardized approach.

Effects of post-exercise sodium bicarbonate ingestion on acid-base balance recovery and time-to-exhaustion running performance: a randomised crossover trial in recreational athletes

This study investigated the effect of post-exercise sodium bicarbonate (NaHCO₃) ingestion on acid-base balance recovery and time-to-exhaustion (TTE) running performance. Eleven male runners (stature, 1.80 ± 0.05 m; body mass, 74.4 ± 6.5 kg; maximal oxygen consumption, 51.7 ± 5.4 mL·kg^-1·min^-1) participated in this randomised, single-blind, counterbalanced and crossover design study. Maximal running velocity (v-V̇O_2max) was identified from a graded exercise test. During experimental trials, participants repeated 100% v-V̇O_2max TTE protocols (TTE1, TTE2) separated by 40 min following the ingestion of either 0.3 g·kg^-1 body mass NaHCO₃ (SB) or 0.03 g·kg^-1 body mass sodium chloride (PLA) at the start of TTE1 recovery. Acid-base balance (blood pH and bicarbonate, HCO₃^-) data were studied at baseline, post-TTE1, after 35 min recovery and post-TTE2. Blood pH and HCO₃^- concentration were unchanged at 35 min recovery (p > 0.05), but HCO₃^- concentration was elevated post-TTE2 for SB vs. PLA (+2.6 mmol·L^-1; p = 0.005; g = 0.99). No significant differences were observed for TTE2 performance (p > 0.05), although a moderate effect size was present for SB vs. PLA (+14.3 s; g = 0.56). Post-exercise NaHCO₃ ingestion is not an effective strategy for accelerating the restoration of acid-base balance or improving subsequent TTE performance when limited recovery is available. Novelty: Post-exercise sodium bicarbonate ingestion did not accelerate the restoration of blood pH or bicarbonate after 35 min. Performance enhancing effects of sodium bicarbonate ingestion may display a high degree of inter-individual variation. Small-to-moderate changes in performance were likely due to greater up-regulation of glycolytic activation during exercise.

Extracellular buffer choice influences acid-base responses and gastrointestinal symptoms

To compare the bicarbonate kinetics and gastrointestinal (GI) symptom responses between an equal dose of sodium bicarbonate and sodium citrate using delayed-release capsules. Thirteen active males (age 20.5 ± 2.1 y, height 1.8 ± 0.1 m and body mass [BM] 76.5 ± 9.6 kg) consumed either 0.3 g^.kg^-1 BM sodium bicarbonate, sodium citrate or a placebo, using a double-blind, randomized crossover design. Blood bicarbonate ion (HCO₃^-) concentration, pH and GI symptoms were measured pre-consumption and every 10 min for 180 min post-consumption. Blood HCO₃^- concentration (P < 0.001) and pH (P = 0.040) were significantly higher in the sodium bicarbonate condition compared with sodium citrate condition up to 3 h post-consumption. Peak blood HCO₃^- concentration was significantly higher with the sodium bicarbonate compared with citrate (P < 0.001). Mean GI symptom scores were lower (P = 0.037) for sodium citrate (1.5 ± 1.8 AU) than bicarbonate (2.6 ± 3.1 AU), with considerable inter-individual variability. No GI symptoms were reported following consumption of the placebo. Both substances increase HCO₃^- values significantly, with sodium bicarbonate causing significantly higher pH and HCO₃^- values than the same dose of sodium citrate, but results in slightly more severe GI symptoms.

Is Individualization of Sodium Bicarbonate Ingestion Based on Time to Peak Necessary?

PURPOSE

To describe the reliability of blood bicarbonate pharmacokinetics in response to sodium bicarbonate (SB) supplementation across multiple occasions and assess, using putative thresholds, whether individual variation indicated a need for individualized ingestion timings.

METHODS

Thirteen men (age 27 ± 5 yr; body mass [BM], 77.4 ± 10.5 kg; height, 1.75 ± 0.06 m) ingested 0.3 g·kg BM SB in gelatine capsules on three occasions. One hour after a standardized meal, venous blood was obtained before and every 10 min after ingestion for 3 h, then every 20 min for a further hour. Time to peak (Tmax), absolute peak (Cmax), absolute peak change ([INCREMENT]Cmax), and area under the curve were analyzed using mixed models, intraclass correlation coefficient, coefficient of variation and typical error. Individual variation in pharmacokinetic responses was assessed using Bayesian simulation with multilevel models with random intercepts.

RESULTS

No significant differences between sessions were shown for blood bicarbonate regarding Cmax, [INCREMENT]Cmax or area under the curve (P > 0.05), although Tmax occurred earlier in SB2 (127 ± 36 min) than in SB1 (169 ± 54 min, P = 0.0088) and SB3 (159 ± 42 min, P = 0.05). Intraclass correlation coefficient, coefficient of variation, and typical error showed moderate to poor reliability. Bayesian modeling estimated that >80% of individuals from the population experience elevated blood bicarbonate levels above +5 mmol·L between 75 and 240 min after ingestion, and between 90 and 225 min above +6 mmol·L.

CONCLUSIONS

Assessing SB supplementation using discrete values showed only moderate reliability at the group level, and poor reliability at the individual level, whereas Tmax was not reproducible. However, when analyzed as modeled curves, a 0.3-g·kg BM dose was shown to create a long-lasting window of ergogenic potential, challenging the notion that SB ingestion individualized to time-to-peak is a necessary strategy, at least when SB is ingested in capsules.

Sodium Bicarbonate Ingestion Improves Time-to-Exhaustion Cycling Performance and Alters Estimated Energy System Contribution: A Dose-Response Investigation

This study investigated the effects of two sodium bicarbonate (NaHCO₃) doses on estimated energy system contribution and performance during an intermittent high-intensity cycling test (HICT), and time-to-exhaustion (TTE) exercise. Twelve healthy males (stature: 1.75 ± 0.08 m; body mass: 67.5 ± 6.3 kg; age: 21.0 ± 1.4 years; maximal oxygen consumption: 45.1 ± 7.0 ml.kg.min⁻¹) attended four separate laboratory visits. Maximal aerobic power (MAP) was identified from an incremental exercise test. During the three experimental visits, participants ingested either 0.2 g.kg⁻¹ BM NaHCO₃ (SBC2), 0.3 g.kg⁻¹ BM NaHCO₃ (SBC3), or 0.07 g.kg⁻¹ BM sodium chloride (placebo; PLA) at 60 min pre-exercise. The HICT involved 3 × 60 s cycling bouts (90, 95, 100% MAP) interspersed with 90 s recovery, followed by TTE cycling at 105% MAP. Blood lactate was measured after each cycling bout to calculate estimates for glycolytic contribution to exercise. Gastrointestinal (GI) upset was quantified at baseline, 30 and 60 min post-ingestion, and 5 min post-exercise. Cycling TTE increased for SBC2 (+20.2 s; p = 0.045) and SBC3 (+31.9 s; p = 0.004) compared to PLA. Glycolytic contribution increased, albeit non-significantly, during the TTE protocol for SBC2 (+7.77 kJ; p = 0.10) and SBC3 (+7.95 kJ; p = 0.07) compared to PLA. GI upset was exacerbated post-exercise after SBC3 for nausea compared to SBC2 and PLA (p < 0.05), whilst SBC2 was not significantly different to PLA for any symptom (p > 0.05). Both NaHCO₃ doses enhanced cycling performance and glycolytic contribution, however, higher doses may maximize ergogenic benefits.

The Impact of Individualizing Sodium Bicarbonate Supplementation Strategies on World-Class Rowing Performance

Contemporary meta-analyses have generally demonstrated a positive effect of sodium bicarbonate (NaHCO₃) supplementation on exercise performance. However, despite these claims, there is limited data on contrasting individualized and standardized timing of NaHCO₃ ingestion prior to exercise to further enhance performance outcomes.

Purpose: To determine whether NaHCO₃ ingestion timing impacts 2,000-m rowing time-trial (TT) performance in elite-level rowers (Senior National team including Olympic/World Championships level) adhering to their own individualized pre-race strategies (e.g. nutrition, warm-up, etc.).

Methods: Twenty three (n = 23) rowers across two research centers (using the exact same methods/protocols) completed three trials: NaHCO₃ loading profile at rest to determine the individual's time-to-peak bicarbonate concentration [HCO3-], followed by two randomized 0.3 g·kgBM⁻¹ NaHCO₃ supplementation experimental trials conducted at different time points [consensus timing (CON): TT performed 60 min post-NaHCO₃ ingestion; and individualized peak (IP): TT performed at the rower's individual peak [HCO3-] determined from the profiling trial post-NaHCO₃ ingestion].

Results: There was a significant mean difference of +2.9 [± 0.4 mmol·L⁻¹HCO3- for IP vs. CON (95% CI 2.0 to 3.8 mmol·L⁻¹); p = 0.02; d = 1.08] at pre warm-up, but not immediately prior to the TT (post warm-up). Performance times were significantly different between IP (367.0 ± 10.5 s) vs. CON (369.0 ± 10.3 s); p = 0.007; d = 0.15).

Conclusions: The present study demonstrated a small but significant performance effect of an individualized NaHCO₃ ingestion strategy. Similarities after warm-up between pre-TT sHCO3- values (CON ~ + 5.5 mmol·L⁻¹; IP ~ + 6 mmol·L⁻¹), however, would suggest this effect was not a result of any meaningful differences in blood alkalinity.

Effects of Dietary Supplements on Adaptations to Endurance Training

Endurance training leads to a variety of adaptations at the cellular and systemic levels that serve to minimise disruptions in whole-body homeostasis caused by exercise. These adaptations are differentially affected by training volume, training intensity, and training status, as well as by nutritional choices that can enhance or impair the response to training. A variety of supplements have been studied in the context of acute performance enhancement, but the effects of continued supplementation concurrent to endurance training programs are less well characterised. For example, supplements such as sodium bicarbonate and beta-alanine can improve endurance performance and possibly training adaptations during endurance training by affecting buffering capacity and/or allowing an increased training intensity, while antioxidants such as vitamin C and vitamin E may impair training adaptations by blunting cellular signalling but appear to have little effect on performance outcomes. Additionally, limited data suggest the potential for dietary nitrate (in the form of beetroot juice), creatine, and possibly caffeine, to further enhance endurance training adaptation. Therefore, the objective of this review is to examine the impact of dietary supplements on metabolic and physiological adaptations to endurance training.

Sodium Bicarbonate Supplementation Does Not Improve Running Anaerobic Sprint Test Performance in Semiprofessional Adolescent Soccer Players

Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. -0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. -1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.

A Novel Ingestion Strategy for Sodium Bicarbonate Supplementation in a Delayed-Release Form: a Randomised Crossover Study in Trained Males

Background

Sodium bicarbonate (NaHCO₃) is a well-established nutritional ergogenic aid, though gastrointestinal (GI) distress is a common side-effect. Delayed-release NaHCO₃ may alleviate GI symptoms and enhance bicarbonate bioavailability following oral ingestion, although this has yet to be confirmed.

Methods

In a randomised crossover design, pharmacokinetic responses and acid-base status were compared following two forms of NaHCO₃, as were GI symptoms. Twelve trained healthy males (mean ± SD age 25.8 ± 4.5 years, maximal oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{\mathrm{V}}{\mathrm{O}}_{2\max } $$\end{document}V˙O2max) 58.9 ± 10.9 mL kg min⁻¹, height 1.8 ± 0.1 m, body mass 82.3 ± 11.1 kg, fat-free mass 72.3 ± 10.0 kg) underwent a control (CON) condition and two experimental conditions: 300 mg kg⁻¹ body mass NaHCO₃ ingested as an aqueous solution (SOL) and encased in delayed-release capsules (CAP). Blood bicarbonate concentration, pH and base excess (BE) were measured in all conditions over 180 min, as were subjective GI symptom scores.

Results

Incidences of GI symptoms and overall severity were significantly lower (mean difference = 45.1%, P < 0.0005 and 47.5%, P < 0.0005 for incidences and severity, respectively) with the CAP than with the SOL. Symptoms displayed increases at 40 to 80 min post-ingestion with the SOL that were negated with CAP (P < 0.05). Time to reach peak bicarbonate concentration, pH and BE were significantly longer with CAP than with the SOL.

Conclusions

In summary, CAP can mitigate GI symptoms induced with SOL and should be ingested earlier to induce similar acid-base changes. Furthermore, CAP may be more ergogenic in those who experience severe GI distress with SOL, although this warrants further investigation.

The effects of sodium bicarbonate ingestion on cycling performance and acid base balance recovery in acute normobaric hypoxia

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.

Does Sodium Citrate Cause the Same Ergogenic Effect As Sodium Bicarbonate on Swimming Performance?

The aim of this study was to investigate the effect of ingesting sodium bicarbonate (SB) and sodium citrate (SC) on 400 m high-intensity swimming performance and blood responses. Six nationally ranked male swimmers (20.7 ± 2.1 yrs; 184 ± 6 cm; 79.9 ± 3.9 kg; 10.6 ± 1% body fat) participated in a double blinded, placebo controlled crossover trial. Ninety minutes after consuming SB (0.3 g·kg^-1), SC (0.3 g·kg^-1) or a placebo (PL) participants completed a single 400-m freestyle maximal test on three consecutive days. The order of the supplementation was randomized. Capillary blood samples were collected on 4 occasions: at rest (baseline), 60 min post-ingestion, immediately post-trial and 15 min post-trial. Blood pH, HCO_3- concentration and base excess (BE) were determined. Blood pH, HCO_3-, BE were significantly elevated from before loading to the pre-test (60 min post-ingestion) (p < 0.05) after SB ingestion, but not after SC ingestion (p > 0.05). Performance times were improved by 0.6% (p > 0.05) after supplementation of SB over PL in 5 out of 6 participants (responders). In contrast, ingestion of SC decreased performance by 0.2% (p > 0.05). No side effects were observed in either trial. Delayed blood response was observed after SC ingestion compared to SB and this provided no or modest ergogenic effect, respectively, for single bout high-intensity swimming exercise. Monitoring the magnitude of the time-to-peak level rise in alkalosis may be recommended in order to individualize the loading time accordingly before commencement of exercise.

The influence of alkalosis on repeated high-intensity exercise performance and acid-base balance recovery in acute moderate hypoxic conditions

Purpose

Exacerbated hydrogen cation (H⁺) production is suggested to be a key determinant of fatigue in acute hypoxic conditions. This study, therefore, investigated the effects of NaHCO₃ ingestion on repeated 4 km TT cycling performance and post-exercise acid–base balance recovery in acute moderate hypoxic conditions.

Methods

Ten male trained cyclists completed four repeats of 2 × 4 km cycling time trials (TT₁ and TT₂) with 40 min passive recovery, each on different days. Each TT series was preceded by supplementation of one of the 0.2 g kg⁻¹ BM NaHCO₃ (SBC2), 0.3 g kg⁻¹ BM NaHCO₃ (SBC3), or a taste-matched placebo (0.07 g kg⁻¹ BM sodium chloride; PLA), administered in a randomized order. Supplements were administered at a pre-determined individual time to peak capillary blood bicarbonate concentration ([HCO₃⁻]). Each TT series was also completed in a normobaric hypoxic chamber set at 14.5% FiO₂ (~ 3000 m).

Results

Performance was improved following SBC3 in both TT₁ (400.2 ± 24.1 vs. 405.9 ± 26.0 s; p = 0.03) and TT₂ (407.2 ± 29.2 vs. 413.2 ± 30.8 s; p = 0.01) compared to PLA, displaying a very likely benefit in each bout. Compared to SBC2, a likely and possible benefit was also observed following SBC3 in TT₁ (402.3 ± 26.5 s; p = 0.15) and TT₂ (410.3 ± 30.8 s; p = 0.44), respectively. One participant displayed an ergolytic effect following SBC3, likely because of severe gastrointestinal discomfort, as SBC2 still provided ergogenic effects.

Conclusion

NaHCO₃ ingestion improves repeated exercise performance in acute hypoxic conditions, although the optimal dose is likely to be 0.3 g kg⁻¹ BM.

Effects of Three-Day Serial Sodium Bicarbonate Loading on Performance and Physiological Parameters During a Simulated Basketball Test in Female University Players

The aim of this study was to investigate the effect of 3-day serial sodium bicarbonate ingestion on repeated sprint and jump performance. Fifteen female university basketball players (23.3 ± 3.4 years; 173.1 ± 5.8 cm; 65.8 ± 6.3 kg; 23.6 ± 4.9% body fat) ingested 0.4 g/kg body mass of sodium bicarbonate or placebo for 3 days (split in three equal daily doses), before completing a simulated basketball exercise. Sprint and circuit times, jump heights, performance decrements, and gastrointestinal side effects were recorded during the test, and blood lactate concentration was measured pre- and posttest. Sodium bicarbonate supplementation led to significant decreases in mean sprint times (1.34 ± 0.23 vs. 1.70 ± 0.41 s, p = .008, 95% confidence intervals [−0.54, −0.10 s]) and mean circuit times (30.6 ± 2.0 vs. 31.3 ± 2.0 s, p = .044) and significantly greater mean jump height (26.8 [range 25.2–34.2] vs. 26.0 [range 25.6–33.6] cm, p = .013) compared with placebo. Performance decrement was significantly less for sprints with sodium bicarbonate compared with placebo (9.9 [range 3.4–37.0]% vs. 24.7 [range 4.1–61.3]%, p = .013), but not different for jumps (13.1 ± 4.5% vs. 12.5 ± 3.1%, p = .321) between conditions. No differences in gastrointestinal side effects were noted between conditions. Significantly greater postexercise blood lactate concentrations were measured in the sodium bicarbonate condition compared with the placebo condition (8.2 ± 2.8 vs. 6.6 ± 2.4 mmol/L, p = .010). This study is the first to show that serial loading of sodium bicarbonate is effective for basketball players to improve repeated sprint and jump performance during competition, or withstand greater training load during practice sessions without any gastrointestinal side effects.

Time to Optimize Supplementation: Modifying Factors Influencing the Individual Responses to Extracellular Buffering Agents

Blood alkalosis, as indicated by an increased blood bicarbonate concentration and pH, has been shown to be beneficial for exercise performance. Sodium bicarbonate, sodium citrate, and sodium or calcium lactate, can all result in increased circulating bicarbonate and have all independently been shown to improve exercise capacity and performance under various circumstances. Although there is considerable evidence demonstrating the efficacy of these supplements in several sports-specific situations, it is commonly acknowledged that their efficacy is equivocal, due to contrasting evidence. Herein, we discuss the physiological and environmental factors that may modify the effectiveness of these supplements including, (i) absolute changes in circulating bicarbonate; (ii) supplement timing, (iii) the exercise task performed, (iv) monocarboxylate transporter (MCT) activity; (v) training status, and (vi) associated side-effects. The aim of this narrative review is to highlight the factors which may modify the response to these supplements, so that individuals can use this information to attempt to optimize supplementation and allow the greatest possibility of an ergogenic effect.

Acute attenuation of fatigue after sodium bicarbonate supplementation does not manifest into greater training adaptations after 10-weeks of resistance training exercise

PURPOSE

In two concurrent studies, we aimed to a) confirm the acute effect of 0.3 g·kg-1 body weight (BW) sodium bicarbonate (NaHCO3) supplementation on central and peripheral mechanisms associated with explosive power (Study 1) and b) determine whether chronic NaHCO3 supplementation would improve the adaptive response of the neuromuscular system during a 10-week resistance training program (Study 2).

METHODS

Eight resistance trained participants volunteered after providing written consent. The experimental design consisted of a week of baseline testing, followed by ten weeks of training with progress measures performed in Week 5. Study 1 involved neuromuscular measurements before and after the leg extension portion of a power based training session performed in Week 1. Changes in maximal torque (MVT) and rates of torque development (RTD), along with other variables derived from femoral nerve stimulation (e.g. voluntary activation, neural recruitment) were analysed to determine the extent of fatigue under NaHCO3 or placebo conditions. Changes in these same variables, coupled with functional 1-repetition maximum leg extension strength, were measured in Study 2 from baseline (Week 0) to Week 5, and again at Week 10.

RESULTS AND CONCLUSION

In Study 1, we observed a decline after the leg extension task in both MVT (~ 30%) and rates of torque production (RTD) irrespective of acid-base status, however the decline in maximal RTD (RTDMAX) was nearly 20% less in the NaHCO3 condition when compared to placebo (mean difference of 294.8 ± 133.4 Nm·s-1 (95% CI -583.1 to -6.5 Nm, p < 0.05)). The primary finding in Study 2, however, suggests that introducing NaHCO3 repeatedly during a 10-week RT program does not confer any additional benefit to the mechanisms (and subsequent adaptive processes) related to explosive power production.

Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions

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.

Sodium bicarbonate improves 4 km time trial cycling performance when individualised to time to peak blood bicarbonate in trained male cyclists

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.

Sodium Bicarbonate Supplementation Delays Neuromuscular Fatigue Without Changes in Performance Outcomes During a Basketball Match Simulation Protocol

Ansdell, P and Dekerle, J. Sodium bicarbonate supplementation delays neuromuscular fatigue without changes in performance outcomes during a basketball match simulation protocol. J Strength Cond Res 34(5): 1369-1375, 2020-To investigate the development of neuromuscular fatigue during a basketball game simulation and to ascertain whether sodium bicarbonate (NaHCO3) supplementation attenuates any neuromuscular fatigue that persists. Ten participants ingested 0.2 g·kg of NaHCO3 (or an equimolar placebo dosage of sodium chloride [NaCl]) 90 and 60 minutes before commencing a basketball game simulation (ALK-T vs. PLA-T). Maximal voluntary isometric contractions (MVICs) of the knee extensors and potentiated high- (100 Hz) and low- (10 Hz) frequency doublet twitches were recorded before and after each match quarter for both trials. In addition, 15-m sprint times and layup completion (%) were recorded during each quarter. Maximal voluntary isometric contraction, 100- and 10-Hz twitch forces declined progressively in both trials (p ≤ 0.05) with a less pronounced decrease in MVIC during ALK-T (p < 0.01). Both 100- and 10-Hz twitch forces were also significantly greater in ALK-T (p ≤ 0.05). Fifteen-meter sprint time increased over the course of both trials (∼2%, p < 0.01); however, no significant condition or time effect was found for layup completion (p > 0.05). A basketball simulation protocol induces a substantial amount of neuromuscular (reduction in knee extensor MVICs) and peripheral fatigue with a concomitant increase in 15-m sprint time over the protocol. NaHCO3 supplementation attenuated the rate of fatigue development by protecting contractile elements of the muscle fibers. This study provides coaches with information about the magnitude of fatigue induced by a simulated basketball game and provides evidence of the efficacy of NaHCO3 in attenuating fatigue.

The Reproducibility of 4-km Time Trial (TT) Performance Following Individualised Sodium Bicarbonate Supplementation: a Randomised Controlled Trial in Trained Cyclists

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.