A lot of emotion is suppressed and the most common one is anger

Psychologist Sandi Mann

One group were invited to express feelings of anger whilst others were told to suppress any feelings.

A third group were asked to switch any angry feelings with a happy memory.

Swearing

They were all then shown a second emotional film and allowed to respond spontaneously.

When they did the women who had suppressed their emotions gave their feelings as being stronger, more angry and more upset.

Many of these women said they felt more like swearing than males.

And one of the key findings was the evidence of a "rebound" effect for emotion.

"The subjective intensity of anger was increased in women by suppressing the expression of that anger," explained Dr Hosie.

Health problems

She said women in many cultures were under pressure to conceal their anger - leaving them more able to develop other strategies for regulating the emotion.

Research also reflected that women benefit more than men from having anger substitution, rather than quashing their feelings.

Psychologist Sandi Mann of the University of Central Lancashire, said concealing angry emotions - in both males and females - can have a bad effect on a person's overall health.

"A lot of emotion is suppressed and the most common one is anger," she said.

"Most would argue suppressing anger is bad for you and can lead to raised blood pressure and other associated problems, but actually expressing anger can also be bad for you."

The best solution is to express the anger, but in a "healthy" way, she advised.

"Having a shouting match is not a good idea but it might be that writing something down is just as effective.

"But each person needs to find their own way of coping with anger - exercise can also be a positive way to work off anger."

Anger management

Her book, Hiding What We Feel, Faking What We Don't, published by Element, delves deeper into the subject of pent-up emotions and how to express them.

Dr Hosie and Dr Alan Milne, who conducted the project jointly, said their findings could be used for further research into this area.

"Despite the knowledge that people experience anger or are the target of other people's anger at least several times a week, there have been very few investigations into the immediate psychological consequences of expressing or suppressing this emotion," said Dr Hosie.

She said the research should be of interest to clinicians and practitioners involved in the treatment of emotional disorders - in particular the development of anger management programmes.