'Stress is increasing dramatically,' said Dr Paul Rosch, president of the American Institute of Stress (AIS), which estimates 1 million workers in the US are absent daily due to stress. 'We estimate it costs American industry $300 billion (£186.6bn) a year in terms of diminished productivity, employee turnover and insurance,' Rosch said.

His institute cites a 2000 Gallup poll, Attitudes in the American workplace, that found that 80 per cent of workers feel stress on the job and nearly half say they need help coping with it. An International Labour Organisation study showed that Americans worked the equivalent of an extra 40-hour week in 2000 compared to 10 years before.

Americans work almost a month longer than the Japanese and three months more than Germans, it said. Latest official figures show US employers are squeezing even more work out of their over-stretched workforce, which is frequently stressed to the eyeballs by the workplace commute before anyone even enters the workplace. A report last week from Hazards magazine concluded workers in the US and elsewhere are now 'entering the karoshi zone,' with work hours pressures now so high workers are dropping dead as a result.

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