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NCT Number: NCT07641335

Effects of Caffeine on Chess Performance and Cognitive Function in Professional Chess Players

This study will examine whether caffeine improves cognitive and competitive performance in professional chess players during tournament-style games. In a randomized double-blind crossover design, participants will complete two experimental sessions in which they consume either caffeinated coffee or decaffeinated coffee before playing a standardized chess match. Cognitive performance will be assessed using attention and reaction-time tests, including the Stroop Test, Trail Making Test, and Puzzle Rush task. Chess performance outcomes such as move accuracy, time management, and error rates will also be evaluated. The study aims to determine whether moderate caffeine intake enhances focus, alertness, and decision-making during prolonged competitive chess play.

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Key information

Conditions

Cognitive Performance Attention Behavior Behavioral Symptoms Caffeine Fatigue Mental Fatigue Pathological Conditions, Signs and Symptoms Reaction Time Signs and Symptoms

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Saint Louis University

St Louis, Missouri, 63104, United States

Location contact

Hossein Rafiei, PhD

CONTACT

[email protected]

1314-977-8675

Hossein Rafiei, PhD

PRINCIPAL_INVESTIGATOR

About this study

This randomized double-blind crossover trial will evaluate the effects of moderate caffeine intake on cognitive and competitive performance in professional chess players. Twelve FIDE-rated chess players will complete two experimental conditions in randomized order: caffeinated coffee and decaffeinated coffee placebo. During each visit, participants will complete standardized cognitive assessments and a tournament-style chess game under controlled laboratory conditions.

Primary outcomes will include objective chess performance metrics derived from chess engine analysis, including move accuracy, centipawn loss, error rates, and time management. Secondary outcomes will include cognitive test performance, tactical reaction time, and self-reported alertness and fatigue. Chess games will be analyzed using standardized software-based evaluation methods.

The crossover design allows each participant to serve as their own control, minimizing variability related to individual differences in skill level, caffeine tolerance, and playing style. The study aims to determine whether caffeine enhances sustained attention, decision-making, and competitive chess performance during prolonged gameplay. Findings may provide insight into nutritional strategies for cognitive performance optimization in mentally demanding competitive environments.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Male and female professional chess players aged 18-50 years
  • Current Fédération Internationale des Échecs (FIDE) standard rating between 2300 and 2600 Elo, or achievement of a standard FIDE rating within this range during the previous 12 months
  • Habitual caffeine consumers consuming ≤2 cups of coffee per day
  • Willingness to comply with all study procedures and study visits
  • Ability to provide written informed consent

Exclusion criteria

  • Non-caffeine users
  • Habitual caffeine intake exceeding 2 cups of coffee per day
  • Cardiovascular disorders
  • Metabolic disorders
  • Psychiatric disorders
  • Pregnancy or breastfeeding
  • Current smoking
  • Shift workers
  • Use of psychoactive medications
  • Participation in another clinical trial within the previous 3 months
  • Known allergy or intolerance to milk proteins, dairy products, or soy
  • Known red-green color blindness or other color vision deficiencies that may interfere with Stroop Test performance

Treatment and study plan

Caffeinated Coffee

Dietary Supplement

Black caffeinated coffee prepared from 15 g of ground coffee brewed in 200 g of water, providing approximately 100 mg of caffeine. The beverage will be consumed approximately 30 minutes before cognitive testing and tournament-style chess gameplay.

Decaffeinated Coffee Placebo

Dietary Supplement

Black decaffeinated coffee prepared from the same batch of coffee beans and matched for taste and appearance to the caffeinated condition. The beverage will be consumed approximately 30 minutes before cognitive testing and tournament-style chess gameplay.

Primary outcomes

  1. Chess Performance Accuracy

    Time frame: 30 minutes after beverage consumption through completion of the tournament-style chess game at each experimental visit.

    Chess performance accuracy will be assessed using engine-based analysis of tournament-style chess games. The primary reported metric will be average centipawn loss per move, with lower values indicating better chess performance accuracy.

Secondary outcomes

  1. Puzzle Rush Correct Responses

    Time frame: Approximately 30 minutes after beverage consumption at each experimental visit.

    Tactical accuracy will be assessed using the 3-minute Puzzle Rush task on Chess.com. The outcome will be the total number of correctly solved tactical puzzles, with higher scores indicating better tactical accuracy.

  2. Puzzle Rush Response Speed

    Time frame: Approximately 30 minutes after beverage consumption at each experimental visit.

    Response speed will be assessed using the 3-minute Puzzle Rush task on Chess.com. The outcome will be average response time per puzzle, with lower values indicating faster response speed.

  3. Stroop Test Performance

    Time frame: Before gameplay and immediately after gameplay at each experimental visit.

    Selective attention will be assessed using the Stroop Test. The outcome will be the change in Stroop Test completion time from before gameplay to immediately after gameplay, with lower completion time indicating better performance.

  4. Trail Making Test Performance

    Time frame: Before gameplay and immediately after gameplay at each experimental visit.

    Cognitive flexibility and processing speed will be assessed using the Trail Making Test. The outcome will be the change in Trail Making Test completion time from before gameplay to immediately after gameplay, with lower completion time indicating better performance.

  5. Self-Reported Alertness

    Time frame: Pre-game and immediately post-game at each experimental visit.

    Self-reported alertness will be assessed using a study-specific visual analog questionnaire. Higher scores will indicate greater perceived alertness.

  6. Self-Reported Mental Fatigue

    Time frame: Pre-game and immediately post-game at each experimental visit.

    Self-reported mental fatigue will be assessed using a study-specific visual analog questionnaire. Higher scores will indicate greater perceived mental fatigue.

  7. Average Time Per Move

    Time frame: From the start of the tournament-style chess game until game completion, assessed over approximately 3 to 4 hours at each experimental visit.

    Chess time management will be assessed as the average time used per move during each tournament-style chess game. This value will be calculated from the total game time divided by the number of moves completed by the participant.

Study contacts

Contact information is provided by the study sponsor or research team.

Hossein Rafiei, PhD

CONTACT

[email protected]

13149778675

Sponsors and collaborators

Lead sponsor

St. Louis University

Other

Registry information

Official study title

GRANDMASTER: Gauging the Role of Alertness and Neurostimulation With Dietary Caffeine in Master-Level Chess; A Double-Blind Randomized Crossover Trial

Acronym: GRANDMASTER

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jun 11, 2026
Registry last updated
Jun 11, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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