Internal Clock: In Your Blood, Not Your Head, Study Finds

Japanese researchers have discovered a molecular signature in blood that can tell time according to a person's internal body clock.

InkFish blogger Elizabeth Preston notes the discovery, which was published in PNAS this week by a team from the Riken Center for Developmental Biology in Kobe, Japan.

The researchers compiled a group of metabolites that allowed them to distinguish whether a person's internal clock is synched with the outside world or not, and how much they differ. The team discovered and tested the signature in a small team of severely jet-lagged (and presumably grumpy) volunteers.

Preston writes that using the new molecular timetable, the Japanese team found that "any pair of blood samples taken 12 hours apart could accurately tell their subjects' body time to within 2 or 3 hours."

According to Preston, this molecular time-taking method could help researchers understand not only how jet-lag and other environment influences can foul the internal clock, but also what she says are "whole families" of pesky genetic early risers.

She points out that if the group can develop their work into a clinical blood test, doctors could use measurements of patient's internal time to more easily diagnose inherited or other sleep disorders or even tailor chemotherapy and other drug treatments to an individual's body clock.