More than a third of workers say they feel 'stressed out' by the number of e-mails they receive in the office and the pressure to respond promptly.

Scottish research found some workers are viewing their inbox up to 40 times each hour, leaving them tired and frustrated - as well as unproductive.

The survey, cited in a BBC report, females felt particularly hard-hit by the deluge.

Internet psychologists said people should relax, and not take their work quite so seriously.

'If you think about the e-mails you receive, how many of them need a reply instantly?' said Graham Jones.

'How many of those e-mails that you send need to go exactly right now? Probably very, very few indeed.'

Only 38 per cent of workers were apparently relaxed enough to wait a day or longer before replying to an e-mail, according to the study of 200 people carried out at Glasgow and Paisley universities.

'E-mail is the thing that now causes the most problems in our working lives,' said lead researcher Karen Renaud, a computer scientist, in the BBC report.

'It's an amazing tool but it's got out of hand.'

Experts suggest a simple stress-beating strategy: check your e-mail less often.

The advice is to set aside two or three dedicated e-mail reading times each day.