Jet Lag

I would really like to understand what happens in the brain with Jet Lag. Before travel was curtailed, I regularly flew to and from London and I always had Jet Lag. Any ideas?

Deep within your brain, located in the front portion of the hypothalamus, is a pacemaker or circadian clock. It is known as the Suprachiasmatic Nuclei or SCN. Its two portions contain about 10,000 neurons . It has two nuclei (portions) containing about 10,000 neurons. Reportedly, the sun clock has a 24-hour rhythm that is about 23 hours and 58 seconds long. The SCN or circadian rhythm clock has an internally driven 24-hour rhythm that tends to run slightly longer than 24 hours by a few minutes. The clock needs to reset itself every day by the sun’s sunlight. If for some reason sunlight cannot enter the eye, the circadian clock does not reset and a non-24 hour syndrome can occur.