Objectives {7}
sleepiness
The main objective is built on the central hypothesis of biomarker discovery in metabolomics: Changes in physiological functions (such as sleep–wake regulation) are reflected in changes of endogenous metabolism and should therefore be detectable as change in metabolic profiles. Virtually all aspects of sleep–wake regulation are, at least in part, genetically determined and therefore, must have a molecular substrate. We hypothesize that increasing sleep drive or impaired wakefulness can be assessed by qualitative or quantitative fluctuations of certain metabolites in biological specimens, e.g., by accumulation or decrease of endogenous substances related to sleep propensity. Furthermore, a connection between metabolic profiling and sleepiness-induced performance impairment (especially the ability to drive) has never been drawn before. This study will allow for creating a reliable and objective panel of candidate biomarkers being indicative for sleepiness and its behavioral outcomes.To avoid the limitations of previous studies, we paid special attention to taking into account specific aspects of human sleep–wake physiology in the study design, as well as the basics and subtleties of biological specimen sampling [