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 [ES_0.5 = 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 [ES_0.5 = 0.18 (0.13–0.24)] and > 10 min [ES_0.5 = 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) [β_Small:Medium = 0.16 (95% CrI 0.02–0.32), β_Small:Large = 0.13 (95% CrI − 0.03 to 0.29)]. SB (192 outcomes) was more effective for performance compared to SC (39 outcomes) [β_SC: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.

中文翻译：

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提高运动能力和表现的细胞外缓冲补充剂：综合系统评价和荟萃分析

背景

细胞外缓冲补充剂 [碳酸氢钠 (SB)、柠檬酸钠 (SC)、乳酸钠/钙 (SL/CL)] 是增效剂，但关于可能改变其效果的因素仍存在疑问。

客观的

量化细胞外缓冲剂对运动结果的主要影响，并使用系统评价和荟萃分析方法研究潜在调节剂对该影响的影响。

方法

本研究是根据系统评价和荟萃分析指南的首选报告项目设计的。搜索了三个数据库以查找根据包含/排除标准筛选的文章。贝叶斯层次元分析和元回归模型被用来研究补充的综合效应和一系列因素对运动和生物标志物反应的调节作用。

结果

纳入 2019 名参与者的 189 篇文章，其中 158 篇涉及 SB 补充，30 篇涉及 SC，7 篇涉及 CL/SL；四项研究提供了缓冲补充剂的组合。补充导致血液碳酸氢盐平均估计增加 + 5.2 mmol L ⁻¹（95% 可信区间 (CrI) 4.7–5.7）。荟萃分析模型发现，与安慰剂相比，补充剂对运动能力和表现具有积极的总体影响 [ES _0.5  = 0.17 (95% CrI 0.12–0.21)]，并可能对运动类型和持续时间、训练状态以及何时进行运动产生调节作用测试是在之前的练习之后进行的。运动持续时间为 0.5-10 分钟 [ES _0.5  = 0.18 (0.13-0.24)] 和 > 10 分钟 [ES_0.5  = 0.22 (0.10–0.33)]。与少量（≤ 4 mmol L ⁻¹ ）相比，当血液碳酸氢盐增加量为中等（4-6 mmol L −1 ）和较大（> 6 mmol L ^{−1 ）时，}获得了对运动影响更大的证据[ β_小：中 = 0.16（95% CrI 0.02–0.32），β_小：大 = 0.13（95% CrI − 0.03 至 0.29）]。与 SC（39 个结果）相比，SB（192 个结果）对性能更有效 [ β _SC:SB  = 0.10（95% CrI - 0.02 至 0.22）]。

结论

细胞外缓冲补充剂会大大增加血液中的碳酸氢盐浓度，从而对运动产生积极的整体影响，其中碳酸氢钠最为有效。确定了几个组级调节因素的证据。这些数据可以指导运动员决定补充缓冲剂是否有益于他们的特定目标。