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Does caffeine added to carbohydrate provide additional ergogenic benefit for endurance?
Scott A Conger1, Gordon L Warren, Michelle A Hardy
1School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA, USA.
Summary
Combining carbohydrate (CHO) with caffeine (CAF) offers a small but significant boost in endurance performance compared to CHO alone. However, the performance enhancement from caffeine is less when combined with CHO than with a placebo.
Area of Science:
- Sports Science
- Exercise Physiology
- Nutritional Science
Background:
- Both carbohydrate (CHO) and caffeine (CAF) are known ergogenic aids that enhance endurance exercise performance.
- Understanding the combined effect of CHO and CAF is crucial for optimizing athletic performance strategies.
Purpose of the Study:
- To systematically review and meta-analyze the literature to determine if ingesting carbohydrate with caffeine (CHO+CAF) yields greater endurance performance benefits than carbohydrate alone (CHO).
- To compare the ergogenic effect of CAF when ingested with CHO versus when ingested with a placebo.
Main Methods:
- A systematic literature search was conducted using keywords related to caffeine, endurance, exercise, carbohydrate, and performance.
- Studies included human subjects performing an endurance task with both a CHO and a CHO+CAF condition.
- Effect sizes (ESs) were calculated using the standardized mean difference to quantify performance changes.
Main Results:
- Twenty-one studies met the inclusion criteria, revealing a small but statistically significant performance benefit for CHO+CAF over CHO (ES = 0.26).
- The performance enhancement from CHO+CAF was not significantly influenced by caffeine dose, exercise duration, or performance test type.
- A subgroup meta-analysis indicated that the performance benefit of caffeine is nearly twofold greater when consumed with a placebo (ES = 0.51) compared to when consumed with carbohydrate (ES = 0.26).
Conclusions:
- Ingesting carbohydrate with caffeine provides a statistically significant, albeit small, improvement in endurance performance compared to carbohydrate alone.
- The ergogenic effect of caffeine on endurance performance is diminished when it is co-ingested with carbohydrate compared to when it is ingested with a placebo.
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