ESP360° at Breakthrough T1D CRC 2026

#47 — The calendar is not biology

Continuous glucose monitoring produces a physiologically continuous signal, but almost every analytical framework cuts that signal at midnight because the calendar says so. Glucose metabolism follows circadian process, not calendar convention.

Peer-reviewed publication: Diabetes Technology & Therapeutics · PubMed

An 89-day CGM series of 25,536 readings was analysed under three temporal representations: conventional 24-hour linear segmentation, higher-resolution linear segmentation, and a circular representation. Post-acceptance reanalysis showed that the reported entropy advantage for circular topology cannot be supported. Under θ = 2πt/24, 36 equal-width linear bins and 36 equal-width angular sectors are the same partition, so their entropies are necessarily identical. Pooled entropy was approximately 4.54 bits at 24 linear bins and 5.12 bits at both 36 linear and 36 angular bins: a bin-resolution effect of about 12.8%, and a topology effect of approximately zero. What survives is narrower. Correlation between the 23:20–00:00 and 00:00–00:40 windows was about r = 0.09 when the two windows were paired within the same calendar date, and about r = 0.97 when the evening was paired with the morning that physiologically followed it, across 89 nights. That is an indexing and pairing effect, not information created by circular coordinates. A correction has been submitted to the journal.