Athletes who travel across more than five time zones are considerably more likely to fall ill when they compete than those who perform where they live, a study has shown.
Research published in the British Journal of Sports Medicine suggested the risk of sickness could be between two and three times higher for people who travel a considerable distance before working out.
Investigators analysed the daily wellbeing of 259 rugby players who were taking part in the Super 14 Rugby Tournament in 2012, which involved teams from South Africa, New Zealand and Australia.
The participants play weekly, high-intensity games at venues in all three nations, with time zones between two and 11 hours different than those they are used to.
It found that in the 16 weeks of the tournament, 187 of the players, or more than 72 per cent, reported suffering from 468 illnesses, which was calculated as creating an overall incidence of 21 ailments per 1,000 player days.
People that have relocated abroad to a country thousands of miles from another nation they regularly exercise in, or those who take part in international sporting events, could find themselves at risk of suffering from a health problem that requires treatment through worldwide expatriate medical insurance.
This is because the incidence was revealed to be 15.4 illnesses for every 1,000 days of sport during matches on home turfs, with this ratio jumping to 32.6 illnesses every 1,000 days when games were played in countries with a time zone of five or more hours different than that at home.
International healthcare experts working for the teams completed a daily log of all of the conditions that required medical treatment for every person in their rugby squad.
Commonplace illnesses included conditions affecting the respiratory system, which represented around 31 per cent of all ailments.
Other commonplace issues included problems in the guts, which were seen in 27.5 per cent of all cases, followed by conditions affecting the skin and soft tissue, which accounted for 22.5 per cent of issues.
Infection rates were not higher when the sportsmen returned to their homeland, which revealed that air travel was not the reason for the correlation.
"The results from our study indicate that the illness risk is not directly related to the travel itself, but rather the arrival and location of the team at a distant destination," the authors wrote.