Internet addiction can reduce immunity according to a new study. Image Credit: Fast Company

Spending too much time online may increase your risk of catching a cold or the flu as excessive internet use can damage immune function, a new study has claimed.

The study by scientists from Swansea and Milan Universities evaluated 500 people aged 18 to 101 years old. It found that those who reported over-using internet also reported having more cold and flu symptoms than those people who did not report excessive internet use.

Around 40% of the sample reported mild or worse levels of internet addiction — a figure which did not differ between males and females. People with greater levels of internet addiction had around 30% more cold and flu symptoms than those with less problematic internet usage.

Previous research has shown that those who spend excessive time on internet experience greater sleep deprivation, have worse eating habits and less healthy diets, engage in less exercise, and tend to smoke and drink alcohol more. These behaviors can harm their immune system and increase vulnerability to diseases.

“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,” said professor Phil Reed of Swansea University.

The study suggested that those who are addicted to internet may suffer from great stress when they are disconnected from it, and this cycle of stress and relief may lead to altered levels of cortisol — a hormone that impacts immune function.

“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,” said Reed.

The study also found that people reported using the internet on average for six hours a day, but a sizable minority of the sample used it for over 10 hours a day — most often connected with social media sites. There were also differences in the way men and women use internet—women using internet for social media and shopping more, and men reporting more use for gaming and pornography.