Keeping up with office e-mails is now one of the worst causes of workplace stress, senior managers have said in a report.

The need to keep up with e-mails came 10th place in a league table of workplace stresses published by the Institute of Management and PPP Healthcare.

It ranked higher than having a bad relationship; lack of influence; working environment or customer complaints for pressure.

Office e-mail systems also contributed to the top two sources of workplace stress - constant interruptions and deadline pressures.

Mark Hastings, director of policy at the Institute, said many managers still did not know how to use e-mails correctly.

He said: "Many people still feel that if they get an e-mail, they have to act upon it instantly, simply because it is an instant message.

"It is adding to the existing time pressures they already face."

Company executives have been urged to act on the pressures before they move into the stress "danger zone".

Almost half of 800 managers surveyed said they were unable to cope with their workloads and struggled to meet targets.

Workload pressures could easily turn to stress, which damaged performance at work as well as personal lives, said the Institute of Management.

Mary Chapman, the institute's director general, said: "Executives find work enjoyable and satisfying but for many, unmanaged workplace pressures are leading to stress, with serious implications for the health and wealth of individuals and organisations.

"Leaders of organisations need to work with individuals to identify and deal with the root causes of stress and develop a healthier workplace culture."

The institute has offered helpful hints on dealing with e-mails including: turning off the instant messaging system that alerts you; Only check your e-mail box twice a day; Reply immediately to acknowledge e-mail but state a proper response will be given later.