CIRCADIAN-RHYTHM ADJUSTMENT - DIFFICULTIES IN ASSESSMENT CAUSED BY MASKING

Measured circadian rhythms consist of endogenous (clock-driven) and ex ogenous (lifestyle-driven) components. The exogenous components cause difficulties of interpretation of phase and amplitude information. Suc h effects can be removed by ''constant routines'', but these protocols are restricted to the laboratory. By contrast, the process of ''purif ication'' of circadian rhythms uses the knowledge of an individual's n ormal lifestyle to separate a measured rhythm into its two components, This method has been shown to be practicable in a variety of circumst ances and to provide a feasible alternative to constant routines.