Effect of Caffeine and Nitrates Combination on Exercise Performance, Heart Rate and Oxygen Uptake: A Systematic Review and Meta-Analysis.
Study Goal
The researchers aimed to analyze whether combining caffeine and nitrates enhances sports performance compared to their isolated ingestion.
Results Summary
The study found that co-supplementation of caffeine and nitrates did not improve performance in time trials or physiological variables over caffeine alone. No synergistic benefits were observed.
Population
Adults (N = 95)
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
caffeine and nitrates supplementation (CAF+nitrates) | no change | time trials (TTs) | adults | - | did not enhance performance | #1 |
caffeine and nitrates supplementation (CAF+nitrates) | no change | exercise performance | adults | - | did not offer further benefits | #2 |
caffeine and nitrates supplementation (CAF+nitrates) | no change | physiological variables | adults | - | did not offer further benefits | #3 |
BACKGROUND: The evidence about the synergy of combining caffeine (CAF) and nitrates on exercise performance has not been summarized, although there is a possibility of additive/synergistic effects of the co-ingestion of these substances given their different mechanisms of action in central (CAF) and peripheral tissues (nitrates). OBJECTIVES: The aim was to analyze the effects of co-supplementation of CAF and nitrates on sports performance in comparison to the isolated ingestion of these substances. METHODS: The databases of PubMed, Web of Science, Medline, CiNAHL and SPORTDiscus were used until June 2024 following PRISMA guidelines. Randomized controlled trials, at least one single-blind trial, conducted in adults were considered. A meta-analysis was performed using the random effects model to calculate the standardized mean difference estimated by Hedges' RESULTS: Six studies were included (N = 95). The meta-analysis revealed that caffeine and nitrates supplementation (CAF+nitrates) did not enhance performance in time trials (TTs) over the CAF alone ( CONCLUSIONS: CAF+nitrates did not offer further benefits on exercise performance or physiological variables from the isolated intake of CAF and nitrates.