Caffeine and Cognitive Function in Sports: A Review & Meta-Analysis

Caffeine is one of the most widely consumed stimulants in the world, commonly used by athletes to enhance both physical and mental performance. In their study, Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis, Lorenzo Calvo et al. explored how caffeine affects cognitive functions such as attention, reaction time, memory, and mood in sports settings. While caffeine is known for its ability to reduce fatigue and increase alertness, its direct impact on cognitive performance during exercise has been less studied. This systematic review analyzed 13 research studies, with five included in a meta-analysis, to determine whether caffeine provides measurable cognitive benefits to athletes. The findings suggest that caffeine significantly enhances attention and self-reported energy levels but does not consistently improve reaction time, inhibitory control, or memory.

Caffeine is one of the most commonly used performance enhancers in the sports world. Athletes rely on it to boost energy, delay fatigue, and improve endurance. However, while much research has focused on how caffeine helps the body, fewer studies have examined its effects on the mind during sports. Cognitive functions—such as attention, memory, and reaction time—play a key role in an athlete’s performance, especially in fast-paced or strategy-heavy sports.

This systematic review and meta-analysis aimed to evaluate how caffeine influences cognitive performance in sports. The researchers analyzed 13 studies to determine whether caffeine improves mental skills like focus and decision-making.

The researchers followed PRISMA guidelines, which ensure systematic and high-quality research reviews. They searched the Medline/PubMed and Web of Science databases for studies published between August 1999 and March 2020.

To be included, studies had to meet strict criteria:

• They needed to be randomized, cross-over trials that compared caffeine intake to a placebo.
• Caffeine had to be consumed as a drink, capsule, gum, or energy bar.
• Participants could be of any age, gender, or training level.
• The study had to measure at least one aspect of cognitive performance in sports, such as reaction time, attention, or memory.

Of the 190 studies initially identified, 13 were selected for the systematic review, and 5 of those were included in the meta-analysis.

One of the most consistent and notable findings in this study was that caffeine significantly improves attention. The meta-analysis showed that athletes who consumed caffeine before or during exercise performed better on attention-related tasks, meaning they could focus more effectively, respond with greater accuracy, and make fewer mistakes compared to those who took a placebo.

In many sports, maintaining attention is just as critical as physical skill. Whether it’s a soccer player tracking multiple opponents, a tennis player anticipating an opponent’s next move, or a basketball player making split-second passing decisions, cognitive sharpness can make the difference between winning and losing. The study strongly supports caffeine’s role in enhancing this ability, stating that "the ingestion of caffeine appears to be an effective measure to enhance an athlete’s attention when training or participating in their given sports activity."

This benefit likely stems from caffeine’s ability to block adenosine receptors in the brain, which reduces the perception of fatigue and keeps the mind more alert. This means that even in long, exhausting matches or intense training sessions, athletes who consume caffeine may be able to sustain their focus and make fewer mental errors.

While many athletes use caffeine to sharpen their reflexes and speed up their reactions, the study found no significant effects on simple reaction time or choice reaction time. This means caffeine did not consistently help athletes react faster, whether that involved a sprinter launching off the blocks, a goalkeeper diving to block a shot, or a fighter dodging a punch.

A possible explanation for this is that reaction time in trained athletes is already near its peak, meaning there may not be much room for improvement. Muscle memory and rapid decision-making are already well-refined in highly skilled individuals, so caffeine may not provide the same boost as it does for focus and attention. This could explain why, despite caffeine’s well-documented benefits for alertness, it does not always translate into quicker reflexes in a sports setting.

Memory and inhibitory control—which refers to the ability to stop or override an impulsive action—were also examined in the study. However, the findings were mixed and inconsistent. Some research suggested caffeine might enhance memory recall, while other studies found no measurable differences between caffeine and placebo conditions. Similarly, caffeine did not show a clear benefit for inhibitory control, meaning it did not necessarily help athletes make better split-second decisions or avoid impulsive mistakes.

This suggests that while caffeine might help maintain sustained attention, it does not necessarily enhance complex decision-making or self-regulation under pressure. In sports like tennis, fencing, or basketball, where quick but controlled actions are required, caffeine may not offer a consistent advantage in preventing impulsive errors or improving recall of game strategies.

Even though caffeine did not consistently improve reaction time or memory, it had a clear impact on how athletes felt during performance. Many reported higher energy levels, improved mood, and lower fatigue after taking caffeine.

One study found that caffeine significantly increased athletes' "ratings of pleasure and arousal," meaning they felt more motivated and engaged during their workouts or competitions. This could be a significant advantage in endurance sports, where mental stamina is just as important as physical endurance.

Feeling mentally energized can also have an indirect impact on performance. When athletes feel less fatigued and more motivated, they may be able to train harder, push through discomfort, and sustain focus even when physically exhausted. While caffeine may not enhance all cognitive functions, its ability to improve mental resilience can still be a valuable tool for athletes across various sports.

The study highlights that caffeine is a powerful tool for improving mental focus and energy levels during sports. However, it is not a magic solution that will instantly enhance every aspect of cognitive performance.

Different factors influence how caffeine affects the brain, including:

• Dosage: Most studies used doses between 3-6 mg/kg of body weight, but some used less or more.
• Timing: Caffeine was usually taken 30-60 minutes before exercise, but some studies provided it during activity.
• Consumption method: Some studies used capsules, drinks, gum, or energy bars, which might affect how quickly caffeine takes effect.
• Type of sport: The cognitive demands of endurance sports (like cycling) versus team sports (like soccer or rugby) could lead to different results.

The findings suggest that caffeine is a valuable supplement for improving attention and energy in sports, making it particularly useful for athletes in fast-paced and strategy-heavy sports. However, if the goal is to improve reaction time or decision-making, caffeine might not offer a guaranteed advantage.

Athletes should consider their individual responses to caffeine, the timing of their intake, and their specific sport’s cognitive demands. Further research is needed to explore optimal dosing strategies and how personal factors like training level and genetics affect caffeine’s impact on mental performance.