Jet lag is a disruption that occurs in two separate but linked areas in your brain.
One area controls your deep sleep and the effects that fatigue has on your body, the other controls the dream phase of your sleep cycle, also known as rapid eye movement or REM sleep.
When jet lag sets in, your body is having a hard time adjusting to a new sleep cycle.
Your natural circadian rhythm or “sleep-wake” pattern will be upset, as will rhythms for eating and working. Your hormone regulation and your body temperature may be out of sync as well.
Of course, a simpler way to view it is that your body is attempting to make sense of the fact that you went to sleep in Dallas and woke up in a far away place like Tokyo.
Some of the unpleasant side effects of jet lag can include:
For each time zone you cross it typically takes one day to recover from jet lag. Recovery time can also be impacted by other factors like your overall health, whether or not you are dehydrated (drink plenty of water!) and other factors specific to your body.