Effects of oral administration of caffeine and D-ribose on mental fatigue.

Abstract

OBJECTIVE:

We examined the effects of administering two different candidate antifatigue substances, caffeine and D-ribose, on mental fatigue.

METHODS:

In a double-blinded, placebo-controlled, three-way crossover design, 17 healthy volunteers were randomized to oral caffeine (200 mg/d), D-ribose (2000 mg/d), or placebo for 8 d. As fatigue-inducing mental tasks, subjects performed a 30-min Uchida-Kraepelin psychodiagnostic test and a 30-min advanced trail-making test on four occasions.

RESULTS:

During the tasks, the task performance of the caffeine group was better than that of the placebo group. However, after the fatigue-inducing tasks, although subjective perception of fatigue, motivation, or sleepiness was not significantly different, plasma branched-chain amino acid levels in the caffeine group were lower than those of the placebo group. Administration of D-ribose had no effect.

CONCLUSION:

Because plasma branched-chain amino acid levels are decreased by mental fatigue, these results suggest that administration of caffeine improved task performance through the enhancement of central nervous system activity without increasing the sensation of fatigue. However, further decreases in branched-chain amino acid levels indicate that caffeine might promote deeper fatigue than placebo. Unfortunately, research subsequent to our study design has shown that D-ribose dosing higher than we used is needed to see a clinical effect and therefore no conclusions can be made from this study as to the efficacy of D-ribose.

• Authors: Suzuka Ataka, Masaaki Tanaka, Satoshi Nozaki, Hiroshi Mizuma, Kei Mizuno, Tsuyoshi Tahara, Tomohiro Sugino, Tomoko Shirai, Yoshitaka Kajimoto, Hirohiko Kuratsune, Osami Kajimoto, Yasuyoshi Watanabe
• Journal: Nutrition (Burbank, Los Angeles County, Calif.) (Nutrition) Vol. 24 Issue 3 Pg. 233-8 (Mar 2008) ISSN: 0899-9007 [Print] United States
• PMID: 18178380 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Amino Acids, Branched-Chain
• Central Nervous System Stimulants
• Caffeine
• Ribose
• Adrenocorticotropic Hormone
• Hydrocortisone

Topics

• Administration, Oral
• Adrenocorticotropic Hormone (blood)
• Adult
• Amino Acids, Branched-Chain (blood)
• Caffeine (administration & dosage, therapeutic use)
• Central Nervous System Stimulants (administration & dosage, therapeutic use)
• Cross-Over Studies
• Double-Blind Method
• Fatigue (blood, drug therapy)
• Female
• Humans
• Hydrocortisone (blood)
• Male
• Mental Processes (drug effects)
• Reaction Time (drug effects)
• Ribose (administration & dosage, therapeutic use)
• Task Performance and Analysis
• Treatment Outcome