Effects of caffeine on productivity and mental fatigue

Coffee Beans

A new study from the Journal of Nutrition shows that caffeine has a positive effect on productivity. The study involved testing the efficacy of two antifatigue substances, caffeine and d-ribose.

Seventeen healthy volunteers were randomised to oral caffeine (200 mg/d), D-ribose (2000 mg/d), or placebo for 8 d.

The candidates were subjected to fatigue-inducing mental tasks: subjects performed a 30-min Uchida-Kraepelin psychodiagnostic test and a 30-min advanced trail-making test on four occasions.

During the tasks, the caffeine supplemented group was better than that of the placebo group. However, post-task fatigue was somewhat different. Though the perceived “…fatigue, motivation, or sleepiness was not significantly different…”, the actual amount of “…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.”

When we get tired due to mental fatigue, plasma branched-chain amino acid (amino acid is protein in its lowest form, e.g. carbohydrate in its lowest form is glucose, fructose etc.) levels decrease.

The results show that the 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.”

“In contrast, long-term fatigue is sometimes irreversible, and the compensation mechanisms that are useful in reducing acute fatigue are no longer effective. In this view, administration of caffeine might introduce unfavourable situations.”


Ataka, S., Tanaka, M., Nozaki, S., Mizuma, H., Mizuno, K., Tahara, T., Sugino, T., Shirai, T., Kajimoto, Y., Kuratsune, H., Kajimoto, O., Watanabe, Y. (2008) ‘ Effects of oral administration of caffeine and D-ribose on mental fatigue’, Nutrition, 24(3), pp. 233-238.


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4 Responses to Effects of caffeine on productivity and mental fatigue
  1. Leslie Levine
    February 7, 2008 | 6:52 pm

    Hi, Health Blogger:

    I think in the same issue of The Journal of Nutrition an editorial ran by energy expert Jacob Teitelbaum, MD, in which he states, “Energy production is an increasingly important topic as the human energy crisis is dramatically escalating. This is reflected in the prevalence of Chronic Fatigue Syndrome (CFS) and its painful cousin Fibromyalgia(FMS), increasing in prevalence from 2% to as high as 8% in the last decade alone 1-6. These syndromes have been associated with hypothalamic dysfunction 7,8 associated with decreased levels of tissue ATP 9,10. Unfortunately, people often deal with fatigue, CFS, and Fibromyalgia by attempting to stimulate systems that are already exhausted, instead of offering treatments that restore energy production. This can give short term benefit, but causes long term problems-which is why caffeine has often been called an energy “loan shark.”

  2. Leslie Levine
    February 7, 2008 | 7:36 pm

    P.S. I thought I’d share the introduction and conclusion of Dr. Teitelbaum’s study, which can be found with complete text in The Journal of Alternative and Complementary Medicine, Vol. 12, No. 9, 2006 . . . Here you go:

    The Use of D-Ribose in Chronic Fatigue Syndrome and Fibromyalgia: A Pilot Study JACOB E. TEITELBAUM, M.D.,CLARENCE JOHNSON, M.S.,2and J.A. St. Cyr, M.D., Ph.D.2

    35 INTRODUCTION Fibromyalgia (FMS), which currently affects an estimated 3 to 6 million Americans,1,2and chronic fatigue syndrome (CFS) are disabling syndromes that often coexist. Patients suffering with these syndromes commonly report severe persistent fatigue, diffuse migratory pain, cognitive dysfunction, and disordered sleep. Many of the clinical symptoms found in FMS/CFS may be related to a decrease in tissue energy levels with altered energy metabolism. Previous reports claim that abnormal muscular energy metabolism frequently can be reflected in pain because of chronic muscle shortening,3postexertional fatigue, and low exercise tolerance associated with decreased cardiac output and stroke volumes.4In addition, it has been postulated that a decrease energy production in these syndromes also may result in hypothalamic dysfunction, which can be reflected clinically as disordered sleep, hormonal imbalances, and autonomic dysfunctions.5Causes and mechanisms for this mitochondrial dysfunction are unknown; however, an alteration in muscle adenine nucleotide metabolism is found, mainly in lower adenosine triphosphate (ATP) levels and depleted energy reserves.6,7 D-Ribose, a naturally occurring pentose carbohydrate, is a key structural component in DNA, RNA, ATP, FADH, coenzyme-A, and NADH needed by the mitochondria to maintain cellular energy homeostasis. Supplemental doses of D-ribose in patients with congestive heart failure and ischemic heart disease have shown a significant improvement in diastolic dysfunction, physical function, exercise tolerance, and quality of life.8D-Ribose has also been reported to be effective in restoring tissue energy levels following intense exercise9 and in an isolated case report of a patient with FMS.10Because of the known energy and functional 1Fibromyalgia and Fatigue Centers, Dallas, TX. 2Valen Labs, Minneapolis, MN.

    CONCLUSIONS This pilot study suggests that D-ribose may provide subjective benefits in patients with FMS and/or CFS. Given the biochemical benefits of D-ribose on increasing muscular energy pools and reducing metabolic strain in affected muscles, the use of this supplement may offer a valuable option for improving quality of life in patients afflicted with FMS and/or CFS.

  3. admin
    February 7, 2008 | 8:46 pm


    Thank you very much for your information and contribution, much appreciated.

  4. TheMediGuy
    October 19, 2009 | 8:25 am

    Great article! Your article reinforces what I was just reading in a Chronic Fatigue Syndrome and Fibromyalgia book, on taking the first step in getting your life back naturally. Information on how to get the Free eBook on how to get rid of Fibromyalgia naturally, can be found at http://ChronicFatigueSyndrome.FibromyalgiaBuzz.com/ .

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