Ask business travellers if they have any fears about flying, and Economy Class Syndrome may have moved up to the top of the list after all the recent publicity over blood clots that can be brought on by long flights in cramped seating.
Frequent flyers are, simply by the law of averages, more at risk, but what about the pilots themselves, who spend most of their working hours in the air, often in the cockpit for more than 10 hours?
A Cathay Pacific pilot tells me he and his colleagues are becoming more aware of the need to take precautions to protect themselves from falling victim to the syndrome, medically known as deep vein thrombosis (DVT).
'I pilot 747-400s on long-haul flights, and the conditions in cockpits are certainly a bit cramped,' he says. 'We have relief crews on long journeys, so when I'm not at the controls I spend a fair bit of time doing stretching and bending exercises at the back of the cabin.
'I know medical experts advise passengers to walk around as much as possible, but of course pilots don't like to stray far from the cockpit.
'On a long-haul flight, the cockpit crew drink a total of around four litres of water to prevent dehydration, which it is believed can contribute towards an attack of DVT.'
He also says he knows that other pilots have died from DVT, one after a blood clot went to his brain (none of them worked for Cathay).