A wealth of scientific research shows us that regularly sitting for long stretches of time has severe consequences for both mental and physical health –and yet computer-based, industrial societies make it extremely difficult to avoid a sedentary lifestyle.

One recently proposed solution to our epidemic of inactivity is to switch from a standard to a standing desk at work; thus boosting activity during the 40 hours a week that adults with office jobs would otherwise spend sitting. Word-of-mouth and marketing campaigns – backed up by very few strong academic studies – have asserted that this set-up can boost productivity and benefit long-term health.

Now, a small study from Australia is challenging the perceived superiority of standing desks with the finding that increased physical discomfort can arise after just two hours of use.  

The investigation, published in the journal Ergonomics, included 20 adults aged 18 to 38 who worked a mix of standing vs sedentary jobs. They were instructed to stand at a properly aligned standing desk and use a computer for two hours, during which body status and mental state were assessed every half hour.

By the end of the experiment, participants reported a significant increase in discomfort in the lower back and lower limb areas, and lower limb swelling was documented. Cognitive tests showed that creative problem-solving skills were maintained throughout the period, but reaction time and fatigue levels worsened.

Although these results must be taken with a massive grain of salt thanks to the tiny study size, lack of a sitting control group, and single data-gathering period, the overall message stands in contrast to the aforementioned small handful of investigations touting the benefit of working upright.

Chief among them is a widely circulated 2015 study suggested that call center employees could be up to 53 percent more productive than their sitting co-workers when given a standing desk set-up for six months. And just last month, a headline-grabbing paper reported that making the switch from sitting to standing at work causes the body to burn 2.5 kilograms (5.5 pounds) of fat over one year.

On closer inspection, however, the first study had a host of problems, and the second one only accounted for metabolic changes and ignored possible side effects.

On the other hand, a well-conducted 12-year study published in the American Journal of Epidemiology found that adults in occupations that involve standing most of the time have twice the risk of heart disease, likely due to chronic pressure in the veins and increased oxidative stress.

And in a painful blow to standing desk legitimacy, a 2016 Cochrane review of 29 studies concluded that there's no quality evidence to support that users of adjustable sit-stand desks actually sit less during the day.

"The bottom line is that this expansion [of standing desks] has been driven more by commercial reasons than scientific evidence," said Alan Taylor, a physiotherapy expert not involved in the research to the Washington Post. "But the evidence is catching up and it's showing there are some drawbacks."