How being addicted to the internet could make you sick: Too much time online weakens the immune system, increasing the risk of colds and flu

• People addicted to the internet are more at risk of colds and flu
• Average time online was six hours a day, but for some it was 10 hours
• Researchers believe people with internet addictions are more secluded and as a result have weakened immune systems
• Lack of interaction with others and less time spent outside exposed to germs increases the risk of succumbing to illness

Spending too much time online can increase your risk of catching a cold or the flu, scientists have warned. 

Those with greater levels of internet addiction are more likely to succumb to illness, than those who spend fewer hours online.

Researchers at the universities of Swansea and Milan believe the reason lies in the fact people with an internet addiction are more secluded, and as a result have weakened immune systems.

They said the lack of interaction with other people and less time spent outside exposing themselves to germs played a role.

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A new study has found that those people who are addicted to using the internet are more likely to fall victim to colds and flu. Researchers believe it is due to a person's immune system being weakened

Past studies have also found people who spend more time online experience greater sleep deprivation, have worse eating habits, engage in less exercise and tend to smoke and drink more alcohol. 

These behaviours can harm their immune system and increase vulnerability to diseases. 

Professor Phil Read, from Swansea University, 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.'

Researchers evaluated 500 people aged 18 to 101 years old.

They found that those who reported problems with excessive use of the internet also suffered more cold and flu symptoms that those who spent less time online.

Around 40 per cent of the sample reported mild or worse levels of internet addiction - a figure which did not differ between males and females. 

People who greater levels of internet addiction had around 30 per cent more cold and flu symptoms than those with less problematic internet usage. 

And researchers found people who are addicted to the internet may suffer from great stress when they are disconnected from the net.

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Scientists said the lack of interaction with other people and less time spent outside exposing themselves to germs played a role

This cycle of stress and relief associated with internet addiction may lead to altered levels of cortisol, a hormone that impacts on the immune system, Professor Read and his team noted.

Professor Read said: 'It may also be that those who spend a long time alone on the internet experience reduced immune function as a result of simply not having enough contact with others and their germs.' 

The team found most people reported using the internet on average for six hours a day.

Meanwhile, a minority admitted to being online for more than 10 hours a day - usually using social media sites.

And researchers noted differences between the way men and women use the internet.

Women showed a propensity to use social media sites and shop online, while men were more likely than women to use the internet for 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.'

The findings come after the same team discovered individuals who a problematic use of the internet become more impulsive after being online.

In 2013 the two universities also found that young people who use the internet for long periods of time can suffer similar withdrawal symptoms to people who mis-use substances.