White paper · June 2026

Photonic Age: A Methodology for Measuring Lost Light Years and the Hidden Cost of Circadian Misalignment

Grant Munro · NIHI Fellow, University of Auckland
The Circadian Foundation · Auckland, New Zealand

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Abstract

Photonic Age quantifies an individual's accumulated deficit of circadian-aligned light exposure as an age offset from chronological age. The gap between the two is their Lost Light Years. This paper presents the three-domain methodology, its foundations in published chronobiology and epidemiology, a worked clinical example, and the commercial translation of Lost Light Years into organisational revenue impact.

01

Three domains

Domain A · Circadian phase alignment
MeasuresHow closely sleep timing tracks the body's internal clock, anchored to DLMO estimates.
SourceTipTraQ sleep architecture, three to seven nights.
Domain B · Social jet lag
MeasuresThe shift between workday and free-day sleep timing: the body living in two time zones at once.
SourceSleep midpoint variance across the study window.
Domain C · Personal light exposure
MeasuresDaily bright-light dose and true-dark duration against circadian need.
SourceLight Time and Dark Time, logged and modelled.

02

Worked example

A 43-year-old senior professional in London, measured over three nights.

2.9h

Light Time

bright light per day

47.2

Photonic Age

4.2 years lost to hibernation

43

Calendar Age

6.8h

Dark Time

true dark per night

Example: senior professional, London, 43 · three-night TipTraQ study

03

Commercial translation

Each Lost Light Year costs an estimated 15 percent of sustained cognitive performance.

Corporate cost formula

Annual cost per person  =  Lost Light Years  ×  Annual salary  ×  0.15

Source: Hafner et al. (2016) · RAND Europe · Why Sleep Matters

The full derivation, sensitivity analysis, and references are in the paper.

Download the full paper (PDF)