The piddock is a two-inch clam-like creature that lives around the British coast and burrows into soft rock.

It glows in the dark when it comes in contact with chemicals produced by human white blood cells. These cells protect the body against disease and raised levels indicate the body is primed for action.

Dr Robert Knight and his wife Dr Jan are farming the molluscs in Plymouth and extracting the protein that causes the bluey-green glow. When the protein is mixed with blood the white blood cell activity can be measured by how much light is produced.

The pair are using their ground breaking work to help British Olympic athletes prepare for the Beijing games and warn them if they are in danger of becoming ill or over-stressed.

They have been advising coaches and nutritionists and spent the past year monitoring the sailing squad.

The Olympic team has been given, and trained to use, a special kit so it can test its competitors in China and send the results to the firm Knight Scientific to analyse back home in Britain.

'We can tell if people are training too hard, because their white cells get hectic," Dr Robert said.

'We can also see the beginnings of infection, so a physician can prescribe antibiotics early on.'

Sports stars are particularly prone to contagious chest infections.

'Our test can help convince the athlete to rest by showing they have over-exercised,' Dr Jan added.  

'We feel this team will do better than ever and we will have had some small part to play in that.'

(Source: Daily Mail)