Genetic cause of being an early or late riser discovered

People who find it difficult to get out of bed early in the day are genetically different from early risers, scientists claim.

German researchers found that when people feel the need to get up is encoded in their genes and the molecules of their skin cells.

They claim that the brain’s hypothalamus works as a central clock for the body, synchronizing all the individual cells, which have their own clocks.

The researchers took skin cell biopsies from 28 volunteers – 11 early risers and 17 late risers – and inserted a bioluminescence gene into the cells.

Their findings, published in the journal Proceedings of the National Academy of Sciences (PNAS), revealed that the treated cells waxed or waned in brightness according to the circadian (daily cycle) phase.

The researchers also measured the brightness to determine the length of the cells’ periods.

Skin cells from extreme early risers had the shortest luminescence periods while those from very late risers had the longest.

The researchers conclude that the “wide range of alterations” suggests “a variety of factors at a cellular level” may determine when people get up.

They add that their work could lead to a “relatively simple” clinical screen to identify patients with extreme circadian rhythms.