LONDON (Reuters) - Regular cups of tea can help speed recovery from stress, researchers from University College London (UCL) said on Wednesday.

Men who drank black tea four times a day for six weeks had lower levels of the stress hormone cortisol than subjects in a control group who drank a tea substitute, the researchers reported in a study published in the journal Psychopharmacology.

The tea drinkers also had a greater feeling of relaxation after performing tasks designed to raise stress levels.

Andrew Steptoe, of UCL's department of Epidemiology and Public Health, and one of the report's authors, said the findings could have important health implications.

"Slow recovery following acute stress has been associated with a greater risk of chronic illness such as coronary heart disease.

"Although it does not appear to reduce the actual levels of stress we experience, tea does seem to have a greater effect in bringing stress hormone levels back to normal."

In the study, 75 tea-drinking men were split into two groups, all giving up their normal tea, coffee and caffeinated drinks. Half were given a fruit-flavoured caffeinated tea mixture made up of the usual constituents of a cup of black tea. The others were given a caffeinated substitute, identical in taste but without the active tea ingredients. Neither the participants or the researchers knew who was drinking real or false tea.

At the end of six weeks the participants were given a series of tests designed to raise their stress levels, including being given five minutes to prepare and deliver a presentation.

The researchers found that stress levels, blood pressure and heart rate rose similar amounts in both groups.

But 50 minutes after the tasks cortisol levels had fallen an average of 47 percent among the tea drinkers, compared to 27 percent in the fake tea group.

Steptoe said it was not known which ingredients in tea were responsible for the effects found in the study.