The more time you spend online, the more likely you are to catch a cold, a new study claims.
Scientists from Swansea and Milan Universities found excessive internet use damages the immune system.
People who surf the internet for longer, they found, are far more susceptible to catching the flu than those that limit their time online.
The study surveyed 500 people aged between 18 and 101 years old.
Forty per cent of the participants admitted to being mildly or significantly addicted to the internet.
That group had 30 per cent more cold and flu symptoms than those who were less attached to the internet.
Researchers found their symptoms were impacted by the fact that internet users suffered stress when they were disconnected from the web.
This cycle of stress and relief led to fluctuating levels of cortisol, a hormone which affects immune function.
Professor Phil Reed of Swansea University’s College of Human and Health Sciences said: ‘We found that the impact of the internet on people’s health was independent of a range of other factors, like depression, sleep deprivation, and loneliness, which are associated with high levels of internet use and also with poor health.’
The average amount of time spent online was six hours a day.
However, a significant minority spent 10 hours a day online, mainly on social media sites.
Gender did not affect levels of internet addiction.
But men and women in the study used the internet for different thing.
Women primarily used the internet for social media and shopping.
Men prioritized gaming and pornography.
Professor Roberto Truzoli from Milan University said: ‘The results on internet usage, apart from being gender stereotypical, were not connected to its impact on immune function.
‘It does not seem to matter what you use it for, if you use it too much, you are more susceptible to illness.
‘However, the mechanisms responsible for you getting ill may differ, depending on how you use the net.’