Why are we going through jet lag so hard?

Rebuilding the internal clock after a flight is not an automatic reaction to light at all. The complex work of thousands of neurons is behind this. A group of scientists from National Taiwan University decided to look deeper — literally. For the first time, they were able to observe how individual cells of the brain’s main chronometer, the suprachiasmatic nucleus (SCN), react in living, awake mice.

The results were unexpected. When the light was turned on in the mice, some neurons became active, while others, on the contrary, quieted down. Surprisingly, the composition of these groups varied from time to time, but their ratio remained stable. This suggests that the brain uses a flexible, balanced network to process light signals— something much more complex than a simple switch.

One of the key participants in the project, Dr. Po-Ting Ye, compares this to the brain’s decision-making process: “We expected to see a simple reaction, like a toggle switch. As a result, they found a system similar to weighing arguments, as if the brain decides for itself whether to shift the clock or not.”

The team was also able to artificially activate a specific group of neurons that normally fire at night and shift the internal clock later. Interestingly, turning on these cells at any time of the day changed the biorhythms of the mice, even when the body usually ignores light.

“This discovery may help create accurate treatments for jet lag and sleep disorders,” says study co—author Professor Shi-Kuo Chen. “Perhaps in the future we will be able to literally rewire a person’s internal clock — without pills and suffering after a flight.”

Now we know that our biological alarm clock is not just a clock, but a complex, sensitive mechanism. And understanding his work opens the way to more subtle management of sleep, vigor and recovery after jet lag.

*Jet lag is a temporary disorder of the circadian rhythms of the body that occurs during rapid transition through several time zones. As a result, the internal biological clock remains synchronized with the original time zone, while the external conditions and the light regime correspond to the new time. This leads to sleep disorders, cognitive decline, fatigue, and discomfort until the circadian rhythms adapt to the new regime.