New methods to assess circadian clocks in humans.

Proper function of the circadian system seems crucial for human health. New advances in methods for assessment of the functional state of the human circadian system facilitate our understanding of the relationship between the disruption of the circadian system and various diseases. Based on the results of such studies, new directions for the diagnosis and treatment of diseases emerge. This communication aims to summarize current methods for evaluating the human circadian system in the laboratory as well as in field studies. The advantages and limitations of the current methods and various approaches used for both in vivo and in vitro assessment of the human circadian system are discussed.