Why the body clock goes haywire with jet lag
The awful sense of disorientation, sleeplessness, and irritability that come with jet lag are enough to ruin anyone's vacation. Given how miserable one can feel for days, it sometimes seems much easier to forgo the dream trip to Europe in favor of a more restful, less fretful journey to a neighboring beach.
But what actually happens? What make us lag so much after taking a jet across time zones?
Those who suffer frequently refer to their "internal clock" getting thrown out of whack. As it turns out, this is not just a metaphor. Residing deep in our brains is such a "clock," the brain's central timekeeper. It's intimidatingly named the suprachiasmatic nucleus, or SCN. A small area located in the part of our brain called the hypothalamus, the SCN is filled with neurons, all with synchronized circadian rhythms that help us regulate sleep and wakefulness.
Researchers in a study published in Current Biology zero in on the SCN in rats. They found that the SCN actually comprises two sections, dorsal and ventral. Rats were exposed to gradually changing light and darkness over a period of seven days, until they were in constant darkness. They looked at changes in the brains and discovered that the two sections of the SCN actually adjusted to the shifts in light at radically different rates. The ventral part of the SCN—which is connected to the light-sensitive retina—adjusted very quickly to the change in light. The dorsal part took days to adjust. The signaling pattern between the two sections gets confused, which sends all sorts of mixed messages throughout the body.
While we all know that humans aren't rats, and rats don't need to know this to plan vacations, the findings may help future treatments for jet lag, beyond, of course, avoiding the vacation altogether.
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