Friday 29 April is On your feet Britain day, which aims to raise awareness of the ill-effects of sedentary working. Noel O’Reilly reports on a recent conference that looked at evidence on the health risks of prolonged sitting at work and what employers should do about it.
“Prolonged sitting is the most underrated health threat of modern time.” So says David Dunstan, head of Physical Activity Laboratory at Baker IDI Heart and Diabetes Institute. Employers should take note, that office workers sit on average 10 hours each day, and 70% of the total time we spend sitting is at work.
Scientific evidence is growing fast on the ill-effects of sedentary working, with a big increase in studies in the last five years and many more in progress. So what should employers be doing about the problem?
In January, experts from around the world gathered to present the evidence for good practice at the Active Working CIC conference in London, “The sedentary office – building the evidence to justify change,” organised by Get Britain Standing.
At the event Active Working, which also organises “On your feet Britain”, got across the message that we should all move around more by making delegates wear different coloured lanyards and asking them to take turns standing up for the talks when their colour was announced.
Gavin Bradley, founding director of Active Working, told delegates that the campaign focuses on: building evidence; education; equipment; making the business case; changing behaviour and culture; and public health policy. The message is that sitting is a learnt behaviour, and employers are advised to recruit a workplace champion to point out “the elephant in the room”.
In 2015, a milestone was reached with the publication of a “consensus statement” by a group of expert academics commissioned by Public Health England (Buckley et al, 2015). This included new recommendations for employers to reduce prolonged periods of sedentary work:
- Accumulate two hours of standing and/or light activity daily during working hours, eventually progressing to four.
- Break up seated work with standing work, regularly.
- Avoid prolonged static sitting (and standing).
- Employers should promote reduction of prolonged sitting alongside other health promotion goals.
There are signs that the Government has realised the importance of the workplace to public health. Last year, a Health at Work Innovation Fund with a £40 million budget was announced, to pilot new and best ways to get people back to work. As well as tackling the disability employment gap, the initiative aims to improve productivity.
The Sedentary Office
The Active Working CIC conference “The Sedentary Office – Building the evidence to justify change” was organised by Get Britain Standing and took place in January 2016.
Also in 2015, the World Health Organisation (WHO) published a physical activity strategy for the European region that recommended workplace adjustments: “The measures could include action to address the workplace layout, such as the provision of adjustable desks, prominent and promotional signs on staircases encouraging their use, regular breaks during the day to allow for physical activity and membership of a gym or sports club.” (WHO, 2015).
Dr James Levine, professor of medicine at the Mayo Clinic, told delegates that studies showed the role of non-exercise activity thermogenesis (NEAT) in our wellbeing. NEAT is the energy expended for everything we do that is not sleeping, eating or sportslike exercise. It varies 2,000 kcal a day because of work and play and is a significant hazard ratio in 34 medical conditions, including metabolic (diabetes, cardiovascular, hypertension), mechanical (arthritis, back pain), malignancy (breast cancer), and mental health (depression, impact on creativity) (Thyfault et al, 2015).
Variation in metabolic rate at work depending on activity, per day
|Occupation type||NEAT kcal a day|
|Seated work, no option of moving||700|
|Seated work, discretion & requirement to move||1,000|
|Standing work, eg homemaker, shop assistant||1,400|
|Strenuous work, eg agriculture||2,300|
|(Data assuming basic metabolic rate: 1600 kcal a day)
Source: Black, European Journal of Clinical Nutrition, Vol 50, no. 72
Dr Jason Gill of the British Heart Foundation Glasgow Cardiovascular Research Centre, said observational studies showed the increased cardio-metabolic risks of too much sitting (Wilmot et al. 2012), including:
- all-cause mortality >49%;
- cardiovascular mortality >90%;
- cardiovascular disease >147%;
- diabetes >119%; and
- depression >25%.
Dr Stacey Clemes, senior lecturer in human biology at Loughborough University, cites research showing that physically active individuals sitting for more than 10 hours a day have a 48% increased risk of the metabolic syndrome (the medical term for a combination of diabetes, high blood pressure and obesity), compared with those sitting for fewer than six hours a day (Petersen et al 2014). Other research has demonstrated that chronic disease risk increases with sitting durations of more than eight hours a day (George et al 2013).
Gill says studies using devices attached to people to measure the amount of movement they make, or measurements of individual’s blood sugar levels, have shown a correlation between sitting and coronary heart disease, and increased risk of cancer. Clemes concludes from her study of office workers that they accumulate high volumes of sitting (about 10 hours a day), and that sitting for more than eight hours a day has been linked to poor health outcomes.
The research shows that 60% of total daily sitting time occurs at work (Clemes et al, 2015), and the consistency of daily sitting among office workers, is more than 10 hours on a work day in different domains. This was lower on non-work days.
“Really, this highlights the importance of the workplace as an environment that promotes sitting, how much sitting time is acceptable, also how much you break up your sitting time,” says Clemes.
How much sitting is too much?
Studies show that more than eight hours of sitting seem to lead to increased heart risk, according to Clemes.
A paper commissioned by Public Health England (Buckely et al, 2015) concluded that “for those occupations which are predominantly desk-based, workers should aim to initially progress towards accumulating 2h/day of standing and light activity (light walking) during working hours, eventually progressing to a total accumulation of 4h/day (pro-rated to part-time hours). To achieve this, seated based work should be regularly broken up with standing-based work, the use of sit-stand desks, or the taking of short active standing breaks.”
However, Veerle Hermans, professor of ergonomics at the Free University of Brussels says that standing for too long could be as risky as sitting, in particular causing varicose veins and back pain. Hermans suggested following the guideline of Alan Hedge, professor of ergonomics at Cornell University, who said that to get the right balance, workers should sit 20 minutes out of every half hour at work, or stand for eight minutes and move around for at least two minutes in a 28-8-2 breakdown.
MSDs and sedentary working
Musculoskeletal disorders (MSDs) account for more than 200 conditions affecting the bones, joints and connective tissue. Some are episodic, short-term and require no specific interventions (eg back pain). Some are diseases that are progressive in nature and require medical interventions, such as drugs or surgery. All have some impact on attendance and productivity.
Stephen Bevan, director of The Work Foundation, argues that MSDs are a much bigger problem for the workplace than employers and public policy makers currently recognise.
“All the attention in the press is on mental health,” says Bevan. “It’s almost as if MSDs are boring and we have to focus on something more sexy, like mental health.” He said the co-morbidity between mental health and MSDs was not sufficiently accounted for.
The rise in MSDs is happening despite the fact that very few workers are doing physically demanding work. “Obesity and sedentary work habits are clearly making a contribution,” says Bevan. “Bones and joints benefit from physical use.”
Research by the Work Foundation shows the challenges of MSD include:
- days lost remain high despite the decline in physically demanding work;
- obesity and sedentary lifestyles and work habits are making a bigger contribution;
- co-morbidity with mental illness occurs in about one-third of people with MSDs; and
- ageing workforce – there is growing incidence of chronic conditions including MSDs.
Across the EU, 44 million workers have MSDs that are caused by their work, with a cost to the EU each year in lost productivity and sickness absence of 2% of GDP. These conditions account for half of all absences from work.
“I think we need to be thinking about this in a more joined up way,” said Bevan, suggesting that the workplace should be more integrated with public health policies.
Benefits of standing
Much of the research on the benefits of breaks has been done with people who have diabetes, where regular breaks in sitting have shown benefits.
Gaps in between periods of sitting are also associated with: lower waist circumference; lower systolic blood pressure; higher HDL (good) cholesterol levels; lower blood triglyceride levels; lower blood glucose levels; and lower blood insulin levels (Healy et al, 2008).
Another study concludes that: “Breaking up prolonged sitting appears to lead to favourable changes in metabolic parameters such as blood glucose control, with the biggest effects seen in diabetic patients and/or those who are physically inactive, overweight or obese.” (Benatti, 2015).
Hermans said research on the impact of interventions aimed at reducing sitting time showed that “a mix of multiple interventions will more likely reduce sitting time at work”.
Hermans looked at studies which showed the impact of different workplace adjustments. In one, the introduction of a coffee corner, office zone exercise balls, meeting room standing table and a hall zone with table tennis and lounge chairs resulted in a 61-minute decrease in sitting per person after six months, and a 39-minute decrease in sitting after 12 months (Coffeng, 2014).
Another study that changed working conditions and introduced pedometers, face-to-face meetings, motivation for lunch walks and incentives for bicycle commuting or sports activities resulted in a 117-minute decrease in sitting per person after 12 weeks (Ellegast, 2012).
A recent randomised trial (Puig Ribera, 2015) that evaluated the effect of breaking up occupational sitting time by incorporating incidental walking into work tasks, eg moving rather than sitting during lectures and seminars, standing to take phone calls and short walks, found a mean average 17% decrease in sitting after 21 weeks.
Hermans stresses the importance of taking action to sustain behaviour change: “You have to do more after the intervention to make sure that people continue to reduce their sitting behaviour.
“Be careful with dynamic working activities when the task has to be precise.”
Evidence shows that sit-stand desks are effective in reducing office workers’ sitting, at least over the short term. However, employers need to make the same ergonomic assessments as with other desks, says Hermans.
“Don’t forget the basic ergonomic rules when using sit-stand solutions,” she warns. These include: elbow height (table height should be at or slightly below elbow height); screen height, eyes 50-70cm from the screen; and considering daylight issues.
Hermans says employees should avoid static standing for long periods when using sit-stand desks. They should be able to adapt the height of the desk. With desk risers, there needs to be space for documents, and arm support to avoid causing strain in neck and shoulder muscles.
“The key word is change – start from a basic position but don’t forget to move. Offer a combined intervention mix – not one-size-fits-all.”
A study on the use of treadmill desks found that sitting decreased by 29% per day at a 12-week follow up (Schuna et al, 2014). But they will not be sufficient on their own, warns Hermans. She advises that treadmills should be placed where they are most effective, such as in meetings.
Studies also show work performance can decrease when using walking, cycling or standing desks. As the intensity of activity increases, the level of precision and speed of work task fall, including: decreases in typing speed; increases in typing errors; and reduced accuracy of mouse pointing. In studies, cognitive function decreased when using walking and cycling desks. (Straker et al, 2009, Dines et al 2009, Commissaris et al 2014, Torbeyns et al, 2014).
The difficulties facing researchers in this field are illustrated by a study on the proportion of working hours spent sitting, standing and stepping before and during sit-stand desk use (Mansoubi et al, 2015). Sitting at work decreased by 20%, but sitting outside of work increased by 5%. International newspaper headlines chose to focus on the latter, ignoring the reduction in sitting overall.
What employers should do
The most consistent message to emerge from the conference was that a holistic approach using a range of different interventions was the most likely way to reduce sitting time at work.
The campaign recommends the following 10 ways to sit less:
- take regular breaks from sitting by standing up every 30 minutes;
- take the stairs instead of the lift;
- stand up or pace while on the phone;
- walk over to speak to co-workers, instead of emailing them;
- move your rubbish bin away from your desk;
- limit screen time to stay active;
- drink lots of water for frequent toilet trips;
- hold a walking meeting;
- hold a standing meeting; and
- try a sit-stand desk.
Levine at the Mayo Clinic recommended using scalable solutions. These could include the following:
- apps such as “Walk n’ play”;
- locating exercise equipment near a place of work;
- holding meetings and performance appraisals on the move;
- centralising waste bins;
- banning email during certain time periods;
- recommending 5-10 minute hourly breaks;
- encouraging people to socialise, visit each others’ desks and “have a laugh”;
- removing chairs to make meetings shorter; and
- using treadmill desks.
Other experts put the problem of prolonged sitting in modern workplaces into a broader wellbeing perspective. Bevan at the Work Foundation recommends that employers should:
- increase physical activity;
- help employees reduce body mass index;
- address ergonomics and workplace design;
- adopt early intervention (diagnosis and referral);
- implement workplace adjustments (prevention and return to work); and
- encourage more “good work”.
“More could be done in more workplaces more simply,” says Bevan. “There’s growing evidence that the psychosocial working environment and the physical environment are very closely connected. Job satisfaction, autonomy and control over tasks, are important. We have to empower line managers to see that this has long-term productivity benefits for them.”
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