The old-fashioned recipe of tough outdoors training & cold baths really is character-building, according to latest research.

Dr Peter Clough from Hull University conducted research among a group of university students to study ways of increasing mental toughness. He took one group up a mountain in Derbyshire and made them put their hands in a bucket of cold water while they answered questions.

The outdoors training increased mental toughness and the ability to face stressful situations, the research found.

Dr Clough said that stressed workers often became hot and sweaty but their condition could be eased if they had a cold bath in the morning.

He is also developing mental toughness courses that do not include physical training.

An increasing number of companies are sending workers to the courses because of growing concerns over the level of stress among British workers, he told delegates at a British Psychological Society conference in Warwick.

"You can toughen people up by sending them up a mountain but the training does not need to be as physically demanding," Dr Clough said.

"The preferred option is to make a job as less stressful as possible but another way is to toughen people up."