Oxidative stress is involved in fatigue induced by overnight deskwork as assessed by increase in plasma tocopherylhydroqinone and hydroxycholesterol

In this study, we examined the relationship between fatigue and plasma concentrations of antioxidants and lipid peroxidation products. Fourteen healthy volunteers performed overnight desk work for 18 h then took a nap for 4 h. Participants answered questionnaires of subjective symptoms of fatigue (QSSF) and completed a self-assessment of fatigue using a visual analog scale (VAS). At each test time, they underwent a critical flicker frequency (CFF) test and blood samples were collected. Plasma levels of alpha-tocopherol (alpha T) decreased and alpha-tocopherylquinone (alpha TQ), the oxidation product of alpha T, increased. The ratio of 7 beta-hydroxycholesterol (7 beta-OHCh), the oxidation product of cholesterol, against total cholesterol increased until the end of experiment. alpha TQ levels correlated with VAS and QSSF scores. The ratio of 7 beta-OHCh to total cholesterol and the value of CFF showed a significant correlation. From these results, plasma levels of alpha TQ and 7 beta-OHCh are useful and objective indicators of fatigue induced by overnight deskwork. (C) 2013 Elsevier B.V. All rights reserved.