Principles of Clinical Chronobiology

Abstract

If one examines living matter as a function of time under appropriate experimental conditions, on the cellular level, in tissue culture or in multicellular organisms, including man, at different levels of physiologic organization one invariably finds nonrandom variations of the variables examined (Aschoff and Wever 1976; Bünning 1973; Conroy and Mills 1970; Halberg 1959; Haus et al. 1980, 1988; Haus and Halberg 1980; Reinberg and Ghata 1964). Many of these time-dependent changes recur in regular intervals and thus represent rhythms, which are to a certain degree predictable in time. With the use of statistical procedures of rhythmometry, a large proportion of the variability encountered in most series of measurements of biologic variables can be shown to be due to a multitude of rhythms in different frequency ranges (Halberg et al. 1965 a, b; Halberg and Panofsky 1961; Halberg and Reinberg 1967; Haus et al. 1980, 1981; Panofsky and Halberg 1961), which may be superimposed upon each other and upon trends, e. g., as a function of aging. Chronobiology is the science investigating and objectively quantifying the mechanisms of this biologic time structure including the rhythmic manifestations of life (Halberg et al. 1977).