In a recent study published in Nutrients, researchers examined the individual and combined effects of caffeine and creatine nitrate on cognitive and exercise performance by resistance-trained athletes.
Study: The Effect of Creatine Nitrate and Caffeine Individually or Combined on Exercise Performance and Cognitive Function: A Randomized, Crossover, Double-Blind, Placebo-Controlled Trial. Image Credit: Ground Picture/Shutterstock.com
Background
Caffeine and creatine are dietary supplements that have demonstrated the ability to enhance training and exercise performance. Caffeine improves strength, muscular endurance, and anaerobic performance via binding to adenosine receptors, namely the A2A subtype.
It also lowers pain and increases neuronal excitability. Creatine replaces adenosine triphosphate (ATP) during anaerobic exercise, thus increasing short-term power output and training volume. However, the interactions between caffeine and creatine are unclear.
About the study
In the present double-blinded, randomized, crossover, placebo-controlled trial, researchers at Jacksonville State University investigated the effects of seven-day high-dose caffeine, creatine nitrate, and their combination on severe intermittent exercise performance and mental attention in resistance-trained athletes.
The team included 18–40-year-olds with ≥2.0 years of experience in multi-joint resistance exercise, no history of metabolic diseases (e.g., cardiovascular disease, diabetes, thyroid conditions, arrhythmia), and no prescription drug use.
They excluded underweight or obese individuals (body mass index below 18.5 or above 24.9), smokers, those who consumed more than 12 alcoholic beverages per week, and those who were allergic to natural stimulants like caffeine.
The researchers conducted the study in controlled settings, which included a 12-hour fast and a 48-hour break from exercise, caffeine, and certain drugs and supplements.
They provided 12 resistance-trained male athletes with creatine nitrate [CN: (4 g creatine; 1 g nitrate), 5.0 g/d plus 0.7 g/d maltodextrin], caffeine (CAF: 400 mg/d + 5 g/d maltodextrin), or a mixture of the two.
The subjects completed standardized resistance exercises (bench and leg press at 70% 1RM) and a Wingate anaerobic power test. The researchers assessed their cognitive performance and cardiovascular responses 45 minutes following the test.
Following the cognitive function test, they measured participants' performance preparedness using the Visual Analog Scale (VAS). The participants also completed detailed questionnaires to assess their sleep quality, coffee use, and any adverse effects they may have encountered.
The athletes provided blood samples for safety examination, which included creatine kinase (CK), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT).
The researchers performed a thorough lipid profile to assess total cholesterol (TC), high-density lipoproteins (HDL), low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), and triglycerides (TG).
Participants completed four sets of three-day food diaries to evaluate their dietary consumption. The Stroop Word-Color Test was used to assess the effects of nutritional supplements on attention, processing speed, and cognitive flexibility.
Results
Creatine nitrate and caffeine combination treatment considerably improved cognitive function, notably in cognitive interference tests, while having little effect on short-term exercise performance.
The Stroop Word-Color Interference test revealed a significant interaction effect between the two supplements, with the CO treatment producing a higher mean score than the CN treatment. The findings indicate that combination supplementation significantly affects cognitive processing.
However, no supplement type showed unambiguous performance improvement across all or most outcomes, indicating a complicated interaction between caffeine and creatine.
The observed gains from baseline in the Stroop Color and Word-Color interference tests following CO supplementation are consistent with previous research confirming creatine's cognitive advantages.
The improved cognitive performance in the CO group may indicate a synergistic impact of creatine when paired with CAF, perhaps increasing cognitive advantages through higher prefrontal cortex activation.
The researchers also found that creatine supplementation had varying effects across different exercise modalities, particularly endurance sports, and in situations where extra body mass might impair performance.
The Wingate test findings demonstrated consistent performance across markers such as peak power, mean power, minimum power, total work, and fatigue index, indicating that caffeine's effects on anaerobic performance are less robust than previously assumed.
The study supports a cautious approach to announcing the efficacy of CN and CAF as performance enhancers, bolstering the necessity for more research to untangle the numerous relationships impacting exercise results.
The absence of significant changes in heart rate and blood pressure before and after exercise supports these supplements' short-term cardiovascular safety.
Conclusion
The study found that consuming creatine nitrate and caffeine together enhances cognition in resistance-trained athletes for up to seven days without causing adverse effects. However, these supplements did not significantly improve exercise performance.
The study validates the short-term safety of these supplements and recommends further investigation into their influences on cognitive and athletic performance over long periods and among varied demographics.
Longitudinal research might provide insight into how these supplements affect muscle growth, intramuscular signaling networks, hormone responses, neuromuscular efficiency, and force generation. Future research should include female athletes to broaden the findings to gender-diverse groups.
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