In this task, you are given an article. Your task is to summarize the article in a sentence.

Both heart rate and blood pressure increased in those who admitted extended time online - along with reported anxiety levels.
There was no such changes for those with no internet-usage problems.
Scientists said it suggested internet addiction is a real physical condition for some people.
The results of the study, which involved 144 participants aged 18 to 33, are published in the journal PLOS ONE.
Study participants had their heart rate and blood pressure measured before and after a brief internet session.
Their anxiety and self-reported internet-addiction were also assessed.
The results showed increases in physiological arousal on ending the internet session for those with problematically-high internet usage.
It follows a study by the two universities in 2013 which showed internet addicts can suffer a form of cold turkey when they stop using the web.
Prof Phil Reed, of Swansea University, said: "We have known for some time that people who are over-dependent on digital devices report feelings of anxiety when they are stopped from using them, but now we can see that these psychological effects are accompanied by actual physiological changes."
Prof Reed, who led the study, said there was an average 3-4% increase in heart rate and blood pressure, and in some cases double that figure, immediately on ending internet use, compared with before use, for those with digital-behaviour problems.
Although this increase is not enough to be life-threatening, the study said, such changes can be associated with feelings of anxiety, and with alterations to the hormonal system that can reduce immune responses.
The study also suggested these physiological changes and accompanying increases in anxiety indicate a state like withdrawal seen for many "sedative" drugs, such as alcohol, cannabis, and heroin.
Prof Roberto Truzoli, of Milan University, a co-author of the study, said: "Whether problematic internet use turns out to be an addiction - involving physiological and psychological withdrawal effects - or whether compulsions are involved that do not necessitate such withdrawal effects - is yet to be seen, but these results seem to show that, for some people, it is likely to be an addiction."
Some people spending excessive time on the internet can show physiological changes similar to drug withdrawal, researchers in Swansea and Milan found.

The woman was being treated for extensive burns at Glasgow Royal Infirmary.
Police were called to a collision involving the woman's red Vauxhall Corsa at about 05:50 on Tuesday.
Officers have appealed for witnesses to the accident, which happened on the A78 Fairlie to Largs road.
Sgt Ian Thornton, from the Divisional Road Policing Unit, said: "Inquiries are ongoing to establish the exact circumstances of the incident, however I would like to speak to anyone who was in the area around the time and may have seen a red Vauxhall Corsa on the road.
"Anyone with information is asked to contact officers at the Divisional Road Policing Unit based at Irvine on 101."
A 46-year-old woman is in a critical condition in hospital after her car hit a lamp post near Hunterston power station in North Ayrshire.

Rachel's Dairy said it was consulting on potential redundancies and reduced hours at its factory in Aberystwyth.
The company said it was doing "everything in our power to minimise the impact on Rachel's consumers and employees".
It is not known how many of its 92 staff could go.
The company's website says it is the largest private sector employer in Aberystwyth, employing staff in roles from production and distribution to sales and food technology.
A Tesco spokesperson said: "We always listen to what our customers want and regularly review the products we offer to ensure we have the best value and range possible.
"Rachel's Dairy products will still be available in some stores in Wales"

Jobs could be lost at a Ceredigion dairy firm after supermarket chain Tesco ended the contract for its yogurt range.

