Elsevier

Nutrition

Volume 24, Issue 4, April 2008, Pages 293-299
Nutrition

Applied nutritional investigation
Antifatigue effects of coenzyme Q10 during physical fatigue

https://doi.org/10.1016/j.nut.2007.12.007Get rights and content

Abstract

Objective

This study examined the effects of coenzyme Q10 administration on physical fatigue.

Methods

In a double-blinded, placebo-controlled, three crossover design, 17 healthy volunteers were randomized to oral coenzyme Q10 (100 or 300 mg/d) or placebo administration for 8 d. As a fatigue-inducing physical task, subjects performed workload trials on a bicycle ergometer at fixed workloads twice for 2 h and then rested for 4 h. During the physical tasks, subjects performed non-workload trials with maximum velocity for 10 s at 30 min (30-min trial) after the start of physical tasks and 30 min before the end of the tasks (210-min trial).

Results

The change in maximum velocity from the 30- to the 210-min trial in the 300-mg coenzyme Q10–administered group was higher than that in the placebo group. In addition, subjective fatigue sensation measured on a visual analog scale in the 300-mg coenzyme Q10–administered group after the fatigue-inducing physical task and recovery period was alleviated when compared with that in the placebo group.

Conclusion

Oral administration of coenzyme Q10 improved subjective fatigue sensation and physical performance during fatigue-inducing workload trials and might prevent unfavorable conditions as a result of physical fatigue.

Introduction

Fatigue is a common symptom in sickness but is also seen in healthy individuals [1], [2], [3]. Interest has recently increased in the use of over-the-counter supplements and naturally occurring nutriceuticals for the attenuation of fatigue. However, there are no established treatment recommendations for fatigue. One of the factors making it difficult to establish treatment recommendations for fatigue was that no adequate fatigue-inducing tasks have been developed. Another was that no proper evaluation methods of fatigue have been found.

Fatigue is best defined as difficulty in initiating or sustaining voluntary activity [4] and can be classified into mental and physical fatigue. We recently succeeded in establishing physical-inducing tests (Nozaki et al., unpublished observations) and in finding evaluation methods for physical fatigue. Therefore, in this study, we attempted to test the effects of candidate antifatigue substances on physical fatigue.

There are numerous reports on the biochemical mechanisms of peripheral fatigue: depletion of glycogen and phosphocreatine, which are physical energy sources; decrease in resting membrane potential or dysfunction of the calcium pump in the sarcoplasmic reticulum in skeletal muscles; and failure of neuromuscular transmission [5]. Thus, exogenous dietary substances involved in energy production are also candidate antifatigue substances for physical fatigue. Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle [6]. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to physical fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defense mechanisms to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Recently, we reported that oral administration of Applephenon (Asahi Breweries, Ltd., Tokyo, Japan), an antioxidant, for 1 wk improved physical performance during fatigue-inducing workload trials on a bicycle ergometer [7]. Accordingly, exogenous dietary antioxidants are candidate antifatigue substances for physical fatigue.

Coenzyme Q10 (2,3 dimethoxy-5 methyl-6-decaprenyl benzoquinone) is a fat-soluble, vitamin-like quinone commonly known as ubiquinone or CoQ [8], [9]. Coenzyme Q10 was first isolated in 1957 in beef mitochondria and is found in the highest concentrations in tissues with high-energy turnover, such as the heart, brain, liver, and kidney [9]. Coenzyme Q10 is a ubiquitous compound vital to energy metabolism. In addition, it is an indispensable compound in the respiratory chain of the inner mitochondrial membrane and acts as an essential antioxidant, assisting in the regeneration of other antioxidants [10], [11], [12]. Therefore, researchers have investigated the effects of coenzyme Q10 as an antifatigue substance during physical load in healthy volunteers [13], [14], [15], [16]. These studies revealed that oral coenzyme Q10 administration (70–100 mg/d for several weeks or months) had no antifatigue effects based on evaluation of exercise performance, oxygen uptake, and lipid peroxidation as compared with placebo administration. However, it is possible that the dose of coenzyme Q10 was inadequate to induce antifatigue effects.

The aim of this study was to test the antifatigue effects of oral administration of 100 and 300 mg/d of coenzyme Q10 using recently established physical fatigue-inducing and evaluation methods (Nozaki et al., unpublished observations).

Section snippets

Subjects

Seventeen healthy volunteers (37.5 ± 9.9 y of age; nine women and eight men; height 163.0 ± 8.1 cm; body weight 58.3 ± 11.3 kg; body mass index 21.9 ± 4.0 kg/m [mean ± SD]) were enrolled in three double-blinded, randomized, placebo-controlled, crossover trials. Participants were recruited by advertisements. Current smokers, subjects with a history of medical illness, taking chronic medication or supplemental vitamins, with a body weight <40 kg, having donated blood within 1 mo before the study,

Results

The baseline scores on the visual analog scale for fatigue in the study group are shown in Figure 1, and other baseline characteristics of the study group are presented in Table 1. In the coenzyme Q10–administered groups, scores on the visual analog scale for fatigue, mean systolic blood pressure, diastolic blood pressure, heart rate, serum CPK, AST, LDH, free fatty acid, cortisol, plasma glucose, ACTH, branched-chain amino acids (BCAAs), alanine, ascorbic acid, tocopherol, and blood lactate

Discussion

We found that oral administration of 300 mg of coenzyme Q10 for 1 wk improved physical performance during fatigue-inducing workload trials on a bicycle ergometer. In addition, subjective fatigue sensation measured using visual analog scales in the 300-mg coenzyme Q10–administered group after the fatigue-inducing physical task and recovery period was lower when compared with that in the placebo group.

To evaluate physical performance with the ergometer, cycling performance, aerobic threshold,

Conclusion

We demonstrated that oral administration of coenzyme Q10 improved subjective fatigue sensation and physical performance during fatigue-inducing workload trials. The present data suggest that administration of coenzyme Q10 might prevent unfavorable conditions as a result of physical fatigue.

Acknowledgments

The authors thank Dr. Tim Jones for editorial help with the manuscript.

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This work was supported in part by Special Coordination Funds for Promoting Science and Technology, and the 21st Century COE Program “Base to Overcome Fatigue”, from the Ministry of Education, Culture, Sports, Science and Technology, the Japanese Government.

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