By Caroline Ryan BBC News Online health staff

Matthew Pinsent overcome with emotion after winning gold

On the podium, Matthew Pinsent himself could not hold in his emotion at winning his fourth gold medal.

But Sunday saw Olympic tears of sadness as British marathon champion Paula Radcliffe had to pull out of her race.

She was distraught - as shown by pictures of the tearful athlete being driven away from the course.

Some of those watching her devastation will have also shed a tear in sympathy at her plight.

But why are the Olympics prompting so many tears?

Crying is cathartic. When tears are shed by the lacrimal gland alongside the eyeball, it is a release for the emotions which have built up inside us.

Letting those feelings out when they get too much is good for us, allowing us to deal with them.

'Powerful experience'

For the athletes, the Olympics is the culmination of years of training.

Watching at home, we get emotional because of empathy - it's something that is built into the human system Professor Windy Dryden, Goldsmiths College Radcliffe baffled by failure Fourth gold for Pinsent

All their hopes and efforts are focussed on what can be just a few seconds or minutes in their lives.

The pressure on them is enormous.

Windy Dryden, professor of psychotherapeutic studies at Goldsmiths College in London, said: "This is a tremendously powerful experience.

"Matthew Pinsent would have been feeling pride, and also relief, exacerbated by listening to the national anthem.

"It's also about the meeting of public expectations. This is happening out in the public arena. It's not a matter of succeeding or failing in private."

Expectations

Paula Radcliffe's tears stemmed from her disappointment at having to pull out of such an important race, feeling the nation's hopes were resting on her.

Professor Dryden said: "It was partly her interpretation of the nation's expectations on here. She probably feels she has let herself down and the nation.

"But we won't feel that because we will be just amazed by her ability to keep going in that extreme heat,"

And why do we cry when we're watching the athletes? It's because we can relate to the highs and lows the athletes are experiencing.

"We can see how the extremes of pride or disappointment are affecting them - and we feel it too," says Professor Dryden.

"Watching at home, we get emotional because of empathy - it's something that is built into the human system."