Long-distance flights through different time zones disrupt your sleep and cognitive functions. People who work in shifts or under bright white light experience the same problems.
Light influences the production of melatonin, the so-called “hormone of darkness”, and melatonin plays a crucial role in the regulation of our wake-sleep cycle.
Daylight and artificial ‘blue’ light ensure that melatonin is not produced. When it darkens at night, melatonin production is set in motion, making us sleepy and tired.