Sitting down for long periods of time and engaging in less-than-social behaviour such as working at a computer, watching television, and playing video games could lead to an increased risk of anxiety, according to the first systematic review of research into the association between sedentary behaviour and anxiety.

As a mental illness, anxiety now affects 27 million people worldwide and 14 percent of adults and 15 percent of 16–24 year-olds Australia. Not only does it come with physical symptoms such as restricted breathing, headaches and a pounding heart, it's also been linked to instances of chronic heart disease and cancer. "Anecdotally, we are seeing an increase in anxiety symptoms in our modern society, which seems to parallel the increase in sedentary behaviour," lead researcher Megan Teychenne from Deakin University said in a press release. "Thus, we were interested to see whether these two factors were in fact linked."

Teychenne and her team analysed the findings of nine studies that investigated the link between anxiety and sedentary behaviour. The sample sizes in these studies ranged from 189 to 13,470, and two involved both young children and adolescents while the others just looked into the association in adults.

In five of the studies, the researchers found a positive association between the number of sitting hours a person does each week and their risk of developing anxiety. "These findings are similar to those found in previous reviews that have assessed the relationship between sedentary behaviour and other specific mental health outcomes such as depression," they write in the journal BMC Public Health.

When it comes to screen time, the research is a bit more scant, but the team did find a study that found that 36 percent of high school students who clocked up more than two hours of screen time per day were more likely to experience instances of anxiety than those who had less than two hours. It's not definitive, but Teychenne thinks there's enough of a link to warrant further research.

The next step would be to investigate why such a link could exist. What is it about sitting down and not talking to anyone for long stretches that can lead to adverse mental effects? While they haven't done any research into it specifically, Teychenne and her team say that it may be because watching tv, playing video games and working into the night can affect a person's sleep patterns, withdraw them from social interactions and relationships, and lead to poor metabolic health. This social withdrawal and the adverse health effects could in turn lead to a chronic feelings of anxiety, they say. 

"It is important that we understand the behavioural factors that may be linked to anxiety - in order to be able to develop evidence-based strategies in preventing/managing this illness," says Teychenne. "Our research showed that evidence is available to suggest a positive association between sitting time and anxiety symptoms, however, the direction of this relationship still needs to be determined through longitudinal and interventional studies."

One thing's safe to assume though - if you feel like you've had too much screen time, you probably have, so take yourself shopping or do something totally old fashioned like calling a friend up and chatting to them on the phone. You've got all the time in the world for sitting.