Caffeine Dose: Performance and Recovery

Ulaç Can YILDIRIM

Status: Completed

Conditions: Caffeine; Healthy Volunteers; Sleep Quality

Treatments: Dietary Supplement: Caffeine 6 mg/kg Oral Powder; Dietary Supplement: Cellulose Powder; Dietary Supplement: Caffeine 3 mg/kg Oral Powder; Dietary Supplement: Caffeine 9 mg/kg Oral Powder

Study type: Interventional

Funder types: Other

Identifiers

NCT07090421

2021/80

Details and patient eligibility

About

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.

Full 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.

Enrollment: 13 patients

Sex: Male

Ages: 20 to 25 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Male university-level rowers
• Aged approximately 22 ± 2.2 years
• Minimum of 2 years of rowing training experience
• Free of any medical condition that impairs exercise participation
• Regular caffeine consumers (habitual daily intake recorded)
• Voluntarily signed informed consent form
• Available to attend all scheduled laboratory sessions

Exclusion criteria

• Any medical condition that could interfere with study participation or protocol adherence
• Use of prescription medications during the study period
• Known allergy to mannitol or other artificial sweeteners
• Diagnosed sleep disorders (e.g., insomnia, sleep apnea)
• Physician's advice to limit or avoid caffeine intake

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Quadruple Blind

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13 participants in 4 patient groups, including a placebo group

Placebo

Placebo Comparator group

Description:

Participants ingested an inert cellulose capsule containing no active substance approximately 60 minutes prior to performing a 2000-meter rowing ergometer time trial. This condition served as the control to compare the effects of caffeine ingestion at varying doses.

Treatment:

Dietary Supplement: Cellulose Powder

Low Dose Caffeine

Experimental group

Description:

Participants ingested a caffeine capsule at a dosage of 3 mg per kg of body mass approximately 60 minutes before the 2000-meter rowing ergometer trial. This condition was included to evaluate the ergogenic and sleep-related effects of a low evening caffeine dose.

Treatment:

Dietary Supplement: Caffeine 3 mg/kg Oral Powder

Moderate Dose Caffeine

Experimental group

Description:

Participants ingested a caffeine capsule at a dosage of 6 mg per kg of body mass approximately 60 minutes before performing the 2000-meter rowing ergometer test. This condition represented a commonly used moderate dose to examine its impact on performance and sleep parameters.

Treatment:

Dietary Supplement: Caffeine 6 mg/kg Oral Powder

High Dose Caffeine

Experimental group

Description:

Participants ingested a caffeine capsule at a dosage of 9 mg per kg of body mass approximately 60 minutes prior to the rowing trial. This high-dose condition was used to assess the maximum ergogenic potential of caffeine and its possible detrimental effects on sleep quality and next-day recovery.

Treatment:

Dietary Supplement: Caffeine 9 mg/kg Oral Powder