Packing until late the night before, setting off early, getting to the airport and carrying luggage, dealing with security and customs, maintaining a cramped posture for a long time, breathing low-oxygen recycled air and interrupting normal sleep and eating patterns… These are all excellent sources of physical exhaustion. Nevertheless, the real reason we feel tired when we travel is not physical, but mental.
Travelling is boring; it involves long periods of waiting for things to happen, there is limited mental stimulation and we mentally classify it as ‘the bit before the fun starts’. On a fly-drive holiday, the driving when you get there never feels as tiring because you are ‘on holiday’. New sights, smells and experiences are constantly engaging your attention and you are no longer waiting for something to begin.