Study: Mental exhaustion at work promotes 1 positive activity

Sitting for long periods of time is linked to heart conditions and increased risk of death, and yet some Americans still sit for about six hours per day.

But, when it comes to sitting, it's doesn't have to be all bad news: A new study suggests that there are some periods of the workday when people tend to have good sitting habits, and some when they need to be particularly wary of staying seated.

Assuming you work a typical 9-to-5 workday, you’re far more likely to move around towards the end of the day, per a study published Monday in Proceedings of the National Academy of Sciences.

According to an analysis of 30,000 movements made by 156 office workers, at 9 a.m. 50 percent of people in the study stood up within 7.1 minutes of sitting and sat down within two minutes of standing.

By 5 p.m., 50 percent of people were likely to stand up after just 4.4 minutes of sitting. Fifty percent of these people still sat back down again within 1.6 minutes.

Overall, participants were 4 percent more likely to stand per minute of sitting, as each hour of the workday passed. They were also 3 percent more likely to sit down per minute of standing up. Taken together, this documents a pattern of increased movement in the afternoon.

That pattern actually makes this type of sitting behavior unique, the study suggests.

Previously, the prevalent thought was that mental fatigue and sitting went hand-in-hand: Other studies have shown that a long, stressful workday is linked with worse performance in endurance exercise. People also tend to avoid activities after mentally exhausting workdays. In one 2009 study, people often said that sports helped them decompress, but they were still less likely to participate in a game after a grueling day at the office.

Here, the study determined that the more mentally tired the office workers were, the more they were inclined to stand — a counterintuitive finding that could be explained by the difference between mental fatigue and physical fatigue.

First author Pam ten Broeke, a Ph.D student who studies the psychology of sedentary behavior at Radboud University, explains that the more mentally exhausted you become, the more likely you are to step away from the screen, which could explain the study's results.

“This is counterintuitive, as you could also expect that at the end of the workday, people feel more mentally fatigued and therefore remain seated for longer time periods," she tells Inverse. "Interestingly, and in contrast to other health behavior, like exercising, people engage in healthier sitting patterns at the end of a mentally fatiguing workday."

Why do we sit? – This analysis of office workers showed that people tend to default to sitting when they’re in an office. Every time one minute of standing passed, participants were 5.4 times more likely to sit back down.

Fifty percent of people sat down within just 1.8 minutes of standing. It took 5.6 minutes of sitting, on average, before 50 percent of people thought to stand back up.

People prefer sitting because it’s the most energy-efficient thing to do, the study suggests. It’s also the one prioritized by most office setups. In 2019, a study of 29 British office workers also noted that people felt that sitting was better suited to cognitively demanding tasks.

However, in this study, the team found that as the day drags on, people tend to stand more, not less.

Ten Broeke suggests that mental fatigue may be driving more standing later in the day simply because people are more focused on their work tasks in the morning, so they tend to switch postures less often.

Fatigue, in itself, acts as a cue that it’s time to stop one task and engage in another, ten Broeke and her colleagues argue.

“At the end of the workday, they are more mentally fatigued, and thereby less concentrated and more restless regarding their work tasks," ten Broeke says. "As a consequence, they more often switch postures while working, or maybe take more quick micro-breaks to, for example, talk to a colleague or get a drink."

However, this is still just a theory. The team didn’t collect any data on mental fatigue as part of the study, so this is conjecture based on previous literature and the patterns they observed throughout the day.

Sitting culture – A March 2019 study suggested that prolonged sedentary behavior was linked to 69,279 deaths in the UK in 2016.

Why do we sit so much if we know the risks? Partially, because it’s hard to imagine an office set up any other way, explains ten Broeke. Social norms regarding sitting can strongly influence our behavior.

“For example, one of the reasons many people give for not standing up enough is that they are afraid that colleagues or supervisors think they are less productive," she says.

That 2019 study on British office workers also found that participants were nervous about how colleagues would respond to standing in the office. However, most of those concerns didn’t come to fruition — some participants reported actually receiving encouragement from coworkers about their standing.

When it comes to working from home there's no social pressure from the office to contend with. But there may be more hours in the workday: A March survey from NordVPN, a private network service provider, found that the workday has increased by three hours since the early days of quarantine.

Whether those longer hours actually translate to more sitting is unclear — ten Broeke says that there is probably no universal pattern. People who work from home may end up sitting more because there are fewer distractions. Others may end up sitting less because their set up requires moving from place to place.

If you are wary of more time in front of a computer and a plunging quarantine step count, ten Broeke suggests redesigning your home office. You can place objects right outside arms reach, remove wheels from your office chair, or use single cups for drinks instead of using larger vessels.

“You could also try to create new stand-up habits, like every time you answer a phone call you stand up,” she adds.

But if this study says anything, it's many of us collapse into that position after minutes away. To fight back against that, making yourself a little bit less comfortable could actually go a long way.

Abstract: Sitting for prolonged periods of time impairs people’s health. Prior research has mainly investigated sitting behavior on an aggregate level, for example, by analyzing total sitting time per day. By contrast, taking a dynamic approach, here we conceptualize sitting behavior as a continuous chain of sit-to-stand and stand-to-sit transitions. We use multilevel time-to-event analysis to analyze the timing of these transitions. We analyze ∼30,000 objectively measured posture transitions from 156 people during work time. Results indicate that the temporal dynamics of sit-to-stand transitions differ from stand-to-sit transitions, and that people are quicker to switch postures later in the workday, and quicker to stand up after having been more active in the recent hours. We found no evidence for associations with physical fitness. Altogether, these findings provide insights into the origins of people’s stand-up and sit-down decisions, show that sitting behavior is fundamentally different from exercise behavior, and provide pointers for the development of interventions.