Nocturnal finger skin temperature in menstrual cycle tracking: ambulatory pilot study using a wearable Oura ring

Maijala, Kinnunen, Koskela, Jämsä, Kangas · 2019 · BMC Women's Health 19(1):150

What this work gives Aellic

Nocturnal FINGER skin temperature across the cycle, measured with an Oura ring: luteal rise +0.30 ± 0.12 °C. That is the lower edge of the range Aellic uses and therefore the cold-start value for `body_temp`. Important for how this is read: skin, not core — distal skin temperature has the LARGER amplitude compared with an oral basal temperature (~0.20–0.23 °C), and skin is exactly what a wearable measures.

Correction of 26 July 2026

The registry attributed a flat “0.30–0.50 °C” to this paper; the 0.50 comes from zhu2021 and the 0.33 from shilaih2018. These are three data sets, not one range from one source.

The entry on the register was wrong. It was not replaced but kept, with what holds instead standing next to it.

Where this sits in the engine

1 declared site: constants and thresholds in the code that point at this entry.

Cycle Phases and cycle-aware baselines 1 site

Also in Cycle

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