NCT07090421

Caffeine Dose: Performance and Recovery

Varying Doses of Evening Caffeine Ingestion Have Different Effects on Rowing Ergometer Performance, Sleep Quality and Wakefulness Scores

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 13 (actual)
• Sponsor: Ulaç Can YILDIRIM · Academic / Other
• Sex: Male
• Age: 20 Years – 25 Years
• Healthy volunteers: Accepted

Summary

The goal of this clinical trial is to learn how different doses of caffeine taken in the evening affect rowing performance, sleep quality, and daytime alertness in trained male university rowers. The main questions it aims to answer are: Does a low, moderate, or high caffeine dose improve rowing performance? How do these doses affect sleep and recovery after evening exercise? Participants completed four rowing tests after consuming either a placebo, low (3 mg/kg), moderate (6 mg/kg), or high (9 mg/kg) dose of caffeine. Researchers measured rowing time, power, heart rate, sleep quality, and daytime sleepiness. The study found that moderate and high caffeine doses improved rowing performance the most. However, these same doses made it harder for participants to sleep well and feel alert the next day. Headaches and stomach issues were also more common with the high dose. The low dose gave smaller performance gains but caused fewer side effects. This study shows that evening caffeine can boost performance but may hurt recovery and sleep. Athletes and coaches should weigh these trade-offs when using caffeine for late-day training or competition.

Detailed description

This double-blind, randomized crossover study examined the dose-dependent effects of evening caffeine ingestion on rowing performance, sleep quality, and daytime alertness in trained male university rowers. The rationale stems from increasing use of caffeine as a performance-enhancing supplement in evening training or competition settings, despite its known adverse effects on sleep and recovery. Thirteen participants completed four experimental trials (placebo, 3 mg/kg, 6 mg/kg, 9 mg/kg caffeine), each separated by a washout period, during which they performed a 2000-meter rowing time trial and were assessed for sleep quality and daytime sleepiness using validated scales. The study also recorded physiological responses and adverse events across conditions. By evaluating multiple doses, the design allowed for assessment of both efficacy and tolerability thresholds, supporting dose-optimization strategies. This study aims to inform practical guidelines for athletes and coaches balancing acute ergogenic benefits with potential recovery trade-offs when caffeine is used late in the day.

Conditions

• Healthy Volunteers
• Caffeine
• Sleep Quality

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Cellulose Powder	Participants consumed an inert cellulose powder dissolved in water, containing no active caffeine. The placebo was ingested orally 60 minutes prior to the rowing performance test. This condition served as the control and was administered once per session in a randomized, double-blind, crossover design.
DIETARY_SUPPLEMENT	Caffeine 3 mg/kg Oral Powder	Participants consumed caffeine in powder form at a dose of 3 milligrams per kilogram of body weight. The powder was dissolved in water and ingested orally approximately 60 minutes before the start of the 2000-meter rowing ergometer performance test. The intervention was administered once per session in a randomized, double-blind, crossover design.
DIETARY_SUPPLEMENT	Caffeine 6 mg/kg Oral Powder	Participants ingested caffeine in powder form, dissolved in water, at a dose of 6 milligrams per kilogram of body mass. The solution was consumed orally 60 minutes prior to the 2000-meter rowing performance test. This intervention was administered once per session as part of a randomized, double-blind, crossover design.
DIETARY_SUPPLEMENT	Caffeine 9 mg/kg Oral Powder	A powdered caffeine dose of 9 milligrams per kilogram was dissolved in water and consumed orally by participants 60 minutes before a 2000-meter rowing ergometer trial. The intervention was administered once per session under a randomized, double-blind, crossover design.

Timeline

• Start date: 2022-07-24
• Primary completion: 2022-08-24
• Completion: 2022-08-24
• First posted: 2025-07-29
• Last updated: 2025-07-29

Locations

1 site across 1 country: Turkey (Türkiye)