Does Caffeine Added to Carbohydrate Provide Additional Ergogenic Benefit for Endurance?

Abstract

Context: Carbohydrate (CHO) and caffeine (CAF) both improve endurance performance. Purpose: To determine by systematic literature review coupled with meta-analysis whether CAF ingested with CHO (CHO+CAF) improves endurance performance more than CHO alone. Methods: Databases were searched using the keywords caffeine, endurance, exercise, carbohydrate, and performance. Criteria for inclusion were studies that used human subjects performing an endurance-exercise performance task and included both a CHO and CHO+CAF condition. Effect sizes (ESs) were calculated as the standardized mean difference. Results: Twenty-one studies met the criteria for analysis. ESs for individual studies ranged from -0.08 (trivial effect favoring CHO) to 1.01 (large effect favoring CHO+CAF). The overall ES equaled 0.26 (95% CI 0.15-0.38, p < .001), indicating that CHO+CAF provides a small but significant performance benefit over CHO. ES was not significantly (p > .05) related to CAF dose, exercise duration, or performance-assessment method. To determine whether ES of CHO+CAF vs. CHO was different than CAF compared with water (placebo), a subgroup meta-analysis compared 36 CAF vs. placebo studies against the 21 CHO+CAF vs. CHO studies. The overall ES for the former group of studies (ES = 0.51, 95% CI 0.40-0.61) was nearly 2-fold greater than in CHO+CAF vs. CHO studies (p = .006). Conclusions: CHO+CAF ingestion provides a significant but small effect to improve endurance performance compared with CHO alone. However, the magnitude of the performance benefit that CAF provides is less when added to CHO than when added to placebo.

Acute post-exercise energy and macronutrient intake in lean and obese youth: a systematic review and meta-analysis

“…Effect sizes (ES) were calculated using a random-effects model that accounts for true variation in effects occurring from study to study, as well as random error within single studies. This random effects model was preferred over a fixed-effect approach as some experimental parameters such as the measurement of EI had wide variation, which is better considered with the random-effects model 195 during analysis (14). Since only one of the included studies reported relative EI, and none provided results for EE, only absolute energy intake was considered in the meta-analysis.…”

“…Subgroup meta-analysis and/or meta-regression were also performed to test whether differences in methodologies could explain the variation in ES between trials (14,18). This analysis included metaregressions of EI as a continuous variable and sub-group meta-analyses were conducted for categorical data such as exercise intensity and body mass status.…”

“…This analysis included metaregressions of EI as a continuous variable and sub-group meta-analyses were conducted for categorical data such as exercise intensity and body mass status. Funnel plots were used to assess publication bias (14,18), in absence of bias, studies should be distributed evenly around the mean ES 210 because of random sampling error. The trim-and-fill correction described by Duval and Tweedie (2000) was used to assess bias (19), which give the possibility to compute and include potentially missing studies to create symmetry about the overall mean ES.…”

Effective Nutritional Supplement Combinations

“…A recent systematic literature review examined the benefi t of co-ingestion of caffeine and carbohydrate ingestion on enduranceexercise performance [ 197 ]. Criteria for inclusion were studies that used human subjects performing an endurance-exercise performance task and included both a carbohydrate and carbohydrate-caffeine condition.…”

Review on analgesic effect of co-administrated ibuprofen and caffeine

“…Caffeine can stimulate the central nervous system, reduce fatigue, stimulate mental activity, improve athletic performance, endurance, and reduce errors caused by workers because of tiredness [5,8,26]. On the other hand, high doses of caffeine can affect coordination, which leads to a poorer than expected athletic performance [36].…”