Researchers believe they have found the genes that help us recover from the grogginess caused by jet lag.
When exposed to light these genes jump into action to balance us out and correct our internal time difference.
University of Oxford scientists also found a protein called SIK1 that shuts off those genes making it difficult for the body to readjust while we travel across time zones.
When the scientists blocked that protein in mice, the animals were able to readjust rapidly from their light/dark cycle.
Before you go cursing the SIK1 protein, keep in mind that it is there to keep the body clock relatively stable. In sum, it's what makes us feel tired at night before bed and what (eventually) wakes us up (on weekends or when we forget to set an alarm).
"The clock needs to be sure that it is getting a reliable signal, and if the signal occurs at the same time over several days it probably has biological relevance. But it is this same buffering mechanism that slows down our ability to adjust to a new time zone and causes jet lag," said Stuart Peirson of Oxford's Nuffield Laboratory of Ophthalmology.
The study was published in the journal Cell.
The research reminds us how everything in the body is regulated by our circadian clock.
This internal clock uses the light that enters our eyes to determine the time of day no matter where we are.
"It would appear that SIK1 plays a common role in our circadian clocks found throughout our body, and works as a hand-brake on our ability to shift our biorhythms and adjust to new time zones, whether these are real or artificial, such as those produced during shift work schedules," said study co-author Giles Duffield, associate professor of biological sciences at Notre Dame, in a statement.