The misalignment of circadian rhythms of body functions is responsible of the so-called “jet lag” (or “shift-lag” in this case) syndrome, characterized by feelings of fatigue, sleepiness, insomnia, digestive troubles, irritability, poorer mental agility, and reduced performance efficiency; a person recovers in a few days depending on the length and duration of the phase shift imposed, personal characteristics (e.g. age), and coping strate- gies.