Figure 25
From: Transdisciplinary unifying implications of circadian findings in the 1950s
Circadian and circaseptan variation in preterm baby's blood pH. As compared to babies at term, prematures routinely monitored longitudinally have provided conclusive data; infradian, notably ~7-day (circaseptan) components in the circulation have an amplitude often larger than the circadians, as illustrated in this figure for blood pH of a very premature boy, JK, born in the 27th gestational week (who was monitored in the hospital for the first 26 months of his extrauterine life) [175]. Values for blood pH during the first five weeks are shown as quadrangles. Two curves are fitted to these data. The lighter curve, representing a model including a 28- and a 178-hour component, fits the data numerically better than the continuous curve corresponding to a model consisting of a precise 1-day and a 7-day component, a finding in keeping with the assumption of built-in free-running circadian and circaseptan rhythms. In this graph, the circadian is represented by the smaller ripples superimposed on the (nearly five) near-weekly cycles of much larger amplitude recurring with a period slightly longer than 7 days. But with either curve-fit, the greater prominence of the circaseptan vs. the circadian amplitude is readily seen. The circaseptan can predominate over the circadian, in humans for the first few weeks of extrauterine life, in a boy born at term, as shown in Figs. 26,27,28,29,30,31, with gliding spectral windows, each presented in two views, to introduce a new fact for circadian scholars and a method applicable further with emphasis also primarily on the circadian and ultradian spectral domains in Fig. 33. Also shown elsewhere [175] are least-squares spectra of 5 consecutive spans, each of about 4 months, showing changes in the development of a spectrum of rhythms. In the first 120 days of very preterm extrauterine life, the peaks corresponding to frequencies lower than 1 cycle/28 hours (infradians) predominate over any circadians, i.e., components with 1 cycle in 20–28 hours also shown elsewhere [175]. The circadian and circasemidian components are expressed by the time of birth, but are free-running and unstable, with a very low amplitude, as compared to circaseptan, circatrigintan (about 30-day) and other infradian components [175].