The invention relates to methods and systems for determining phase-specific parameters of a physiological variable, and a related computer program and a related machine-readable storage medium, which are usable in particular to determine parameters of physiological variables that are subject to circadian variation. To this end, phase-specific parameters of a physiological variable X(t) are determined by calculating, at least for a portion of values x lying in a specifiable time period, a mean g(xτ) in each case of values X(t+τ) for which X(t)=x applies for their predecessors, τ describing a time interval, and determining the phase-specific parameters by evaluating the mean g(xτ).
