Autorhytmometry : Leads from single-sample medical check-ups toward a health science of time series

Starting from the definition of health as given by the WHO, the authors emphasize that rhythms of biological variables should be taken into account if one is to arrive at a positive and individual definition of the concept of health. The evaluation of a single datum spot check of physiological functions does not permit to quantify health in dynamic terms whereas this may become possible when the rhythmic quality of these variables, according to a spectrum of characteristic frequencies, has been assessed. Rhythmometry provides for appropriate reference standards as regards both the population in general and the physical conditions of the same subject during certain spans in the (prospective) life history (spans selected according to consideration of risk and hence cost and benefit at a given age). The authors therefore stress the importance of rhythmometry, thanks to which the time course and other peculiarities of any biological phenomenon can be evaluated by obtaining serial measurements, objectively quantifying their characteristic features, and working out special models with the aid of computers. Of special interest, particularly for the evaluation of reference standards, is autorhythmometry (AR), to be used at least for certain variables. This is the method by which each subject studies himself, performing a certain number of measurements in the course of the day (or month or year) of his body temperature, blood pressure, cardiac rhythm, grip strength, etc. In AR, the subject takes an active part in the study of his condition of health and it has been shown that in the majority of cases these measurements are done with the utmost accuracy and precision, providing that the purpose of the operations to be performed has been adequately explained. The wide spread use of AR, during more or less extended periods in a lifetime, would permit the assessment of the normal situation for each individual and thus offer the possibility of diagnosing any disorder at its very beginning; it would thus be of great prophylactic value. The authors refer to the example of arterial blood pressure; widely different values for the normal levels can be found in the texts of different authors. They also show that a certain pressure may be normal for a given subject at a certain time of day and be a sign of illness for another subject, or even for the same subject at a different time. The authors suggest the introduction of AR in the curriculum of secondary schools and into the routine for outpatients and inpatients. This practice would increase the availability of information on public health at a lower cost. AR may be very usefully applied to chronotherapy: it is a well-known fact that there are rhythms of sensitivity and therefore rhythms of toxic as well as therapeutic effects for various drugs. These can be dove-tailed in such a way as to work out, for individual cases, a time for administration at which the therapeutic effect is at its maximum and the toxic one at its minimum. If this is not the case, it may be useful to modify some features of these rhythms, e.g. by shifting meal times, so as to obtain an optimal therapeutic index.