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

June 8, 2026 updated by: Hossein Rafiei, St. Louis University

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

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

12

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Missouri
      • St Louis, Missouri, United States, 63104
        • Saint Louis University
        • Contact:
        • Principal Investigator:
          • Hossein Rafiei, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Caffeinated Coffee
Participants will consume one serving of 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 completion of cognitive testing and a standardized tournament-style chess game during the experimental visit.
Dietary supplement: Caffeinated Coffee
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.
Placebo Comparator: Decaffeinated Coffee Placebo
Participants will consume one serving of black decaffeinated coffee prepared to match the caffeinated coffee in taste and appearance. The beverage will be consumed approximately 30 minutes before completion of cognitive testing and a standardized tournament-style chess game during the experimental visit.
Dietary supplement: Decaffeinated Coffee Placebo
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
30 minutes after beverage consumption through completion of the tournament-style chess game at each experimental visit.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Approximately 30 minutes after beverage consumption at each experimental visit.
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.
Approximately 30 minutes after beverage consumption at each experimental visit.
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.
Before gameplay and immediately after gameplay at each experimental visit.
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.
Before gameplay and immediately after gameplay at each experimental visit.
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.
Pre-game and immediately post-game at each experimental visit.
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.
Pre-game and immediately post-game at each experimental visit.
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.
From the start of the tournament-style chess game until game completion, assessed over approximately 3 to 4 hours at each experimental visit.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

St. Louis University

Investigators

  • Principal Investigator: Hossein Rafiei, PhD, St. Louis University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 15, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

August 1, 2027

Study Registration Dates

First Submitted

May 24, 2026

First Submitted That Met QC Criteria

June 8, 2026

First Posted (Actual)

June 11, 2026

Study Record Updates

Last Update Posted (Actual)

June 11, 2026

Last Update Submitted That Met QC Criteria

June 8, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SLU-CHESS-CAFF-2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be publicly shared because this is a small pilot study involving highly specialized professional chess players, and there is potential risk of participant identification despite de-identification procedures.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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