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.