Biological rhythms follow a 24-hour cycle. ‘Desynchronosis’, jet lag, results when the body cannot adjust to a new chronological regime. Physical functions fail, including excretion and sleeping, and mental faculties are impaired. I recall a catalogue of horror, an urban grimoire, case studies in a medical textbook that documented the condition. Jetlagged travellers walking into the paths of moving cars, unaware of the speed and motion around them. Driving off cliffs and into lakes. Embarking on violent rampages, just like sleepwalkers.

Jetlagged construction workers falling off radar dishes, hundreds of metres high. Jetlagged businessmen falling asleep in meetings, yet still closing important deals. Once, corporations banned executives from making major decisions within 24 hours of crossing an international time zone. Today, the organism has evolved. If you can sleep with your eyes open, especially during transatlantic business meetings, you are a valuable piece of meat.

William Gibson wrote that jet lag is ‘soul delay’; there is a gap as your soul catches up with your body. When you fly from Europe to Australia, the journey takes 24 hours and you pass through five airports and five time zones. By the time your soul catches up, your body has changed beyond all recognition. In extreme cases, there is no reunion; the docking operation is rejected and your soul is left to drift, alone, in violation of your physiology.