International travel 'makes athletes ill

The researchers argue the different germs and allergens of a new environment affect the athletes.

Air travel does not seem to play a part as on returning home the competitors' health does not differ from normal.

They suggest this could contribute to a home advantage for Team GB in the Olympic Games.

Prof Martin Schwellnus, one of the paper's authors said: "It is a common perception that international travel increases illness - due to organisms in aeroplanes."

However, this study suggests that increased illness from travel is more likely to be due to the fact that the person is out of their normal environment.

Prof Schwellnus added: "The stresses of travelling seem not to affect the players because when they return home the risk of illness does not differ from normal.

"Changes in air pollution, temperature, allergens, humidity, altitude as well as different food, germs and culture could all contribute to illness when arriving in a distant destination."

Read more