The Measurement of Someone's Sleep and Rest Cycles

This page is the CodyCross answer for the clue below from Prehistory, Group 1252, Puzzle 4 (Cairn De Barnenez).

Question is: The Measurement of Someone's Sleep and Rest Cycles

and the answer is: ACTIMETRY

Word Meaning:

ACTIMETRY — The measurement of people's activity / rest cycles

Definitions from Wiktionary.