Almost 40% of workers are spending more than two hours a day dealing with e-mails, leading to lost productivity.
Communications consultancy Expert Messaging has monitored almost 4,000 workers at 150 UK companies over the last 18 months.
It says 39% spend over two hours on e-mail, and 72% spend at least an hour a day on e-mail.
The study also found that employees are hoarding an average of 2,769 e-mails in their inboxes. They receive an average of 34 e-mails per day, 47% of which do not help them do their jobs.
People send on average 24 e-mails per day: roughly two thirds of which are replies, forwards or copies of e-mails sent by others. Only one third is originated by the sender.
Bob Hallewell, managing director at Expert Messaging, said, "Some people spend up to half their working day chained to e-mail.
"Organisations pay almost no attention or provide any guidance on how it should be used. Consequently this widely-used medium generates the greatest levels of misunderstanding between people and is a great source of workplace anxiety and stress."
Expert Messaging has launched an E-mail Charter to improve productivity, reduce stress and communicate more clearly through e-mail.
The charter for e-mail users includes the following:
I will make it clear what I expect from the reader
I will consider the "tone" of my e-mail
I will structure my e-mail to be read as an e-mail
I will include the right amount of information
I will always think about the time elements
I will make sure my e-mail is easy to read
I will always include good contact details
I will consider the legal aspects of my e-mail
I will send it only to people who will find it useful