Even felt disoriented after travelling through several timezones? Felt as if there is no strength in your body anymore? Well the feeling is now backed by science.
According to a report, "Jet-lag due to cross-time-zone travel is thought to result from a disruption of the circadian clock within the human brain. After a rapid shift in time-zones, the brain's oscillatory pacemaker cells cannot instantly establish a rhythm appropriate to the new time-zone."
So, in common English, your brain needs time to identify the new time zone and adjust the body accordingly. It needs even more time when you travel east considering the rotation of Earth as light travels much faster relatively. This period of adjustment is what we call jet lag. So when somebody tells you how its just inside your head, they are actually right!
Title image: Scientiststalkfunny