Global travel is now a normal part of corporate life, with many company managers now taking it for granted that their portfolios stretch to faraway shores. Managers are able to nip off to Singapore or Australia for a couple of days and still be back in time for their weekly meeting.
And yet the effects of jet lag on personal performance are rarely admittted openly by the globetrotting executive. When asked for their views, many executives were terse on the subject, others openly hostile, while yet others obviously considered the whole subject too frivolous.
Frivolous it is not. Perhaps it is a stiff-upper-lip culture that stops jet lag being acknowledged as an issue. This may be a mistake, if dismal reports of the health risks of constant long-haul flying are to be believed.
Last year, lawyer John Eaton ended up in hospital suffering from fatigue, disorientation, dehydration and irregular heartbeat after 22 trips to the Far East. Three of his business partners had died after spending most of their careers travelling overseas.
His experience, and that of others like him, has prompted a new research programme at the Aviation Health Institute (AIH) in Oxford.
Farrol Kahn, the institute's director, points out that we are only now seeing the first generation of regular business travellers approaching retirement, and suggests that a lack of oxygen in aircraft cabins can over a long period of time cause blood disorders and heart problems, while cabin pressures and enforced immobility drain the body of vital minerals, cause disorientation and loss of muscle strength.
Only one or two of Britain's bosses were prepared to break their silence and talk honestly on the subject. 'No allowance is made for jet lag. No matter how hellish you're feeling, you just have to get on with it,' complains Richard Keith, managing director of Scottish & Newcastle's international division. Keith believes that jet lag is not just a minor irritant but a serious impediment to good work performance. 'I am very careful not to make any important decisions after a long flight,' he says: 'Emotionally I can feel a bit strange at first and, coming back from the US it can be five or six days before I feel myself again. I've been conscious of going straight into a meeting and giving a report, and then later wishing I hadn't.'
It's difficult to stop or even cut down on the amount of travelling if that is what the job demands, and our more forthcoming respondents say they have tried everything as a cure - drinking water but no alcohol, alcohol but no water, eating, not eating, and an array of herbal and homeopathic cures. Kahn advises that while adequate sleep is the main cure, drinking several glasses of carrot juice for four days before a flight is a good idea, as this helps offset the effects of reduced oxygen. He also suggests drinking a glass of mineral water every hour during the flight and rejecting airline food and alcohol in favour of pasta or bananas.
This is dismissed by Sir Nigel Mobbs, chairman of Slough Estates. His antidote is to eat and drink everything that is put in front of him. 'It is supposed to be against the rules but it works all right with me,' he says cheerfully.