The study found that both total sedentary time and sedentary duration were associated with a higher risk of death. The greatest risk was found in those who spent more than 12.5 hours a day being sedentary and when bouts persisted for longer than ten minutes at a time.
But before you rush out to buy a standing desk, it’s worth pointing out the limitations to this study. For a start, all the 8,000 participants were aged 45 years and older – so may not be representative of other age groups. Also, activity data was only collected for one week, so this might not be representative of activity levels for the entire study (participants were followed for four years).
In the study, a hip-mounted accelerometer – a device that measures the magnitude of accelerations – was used to measure physical activity. While this is a less biased method than asking participants to recall how much sitting or activity they did in a day, it is still problematic. This is because accelerometer data cannot distinguish between postures such as sitting versus standing, despite being different physiologically and potentially valuable to health.
But despite these limitations, this study reveals an alarming truth: we can simultaneously meet physical activity recommendations but remain sedentary for a significant amount of the day. And this might increase our risk of death.
Indeed, research in Australian adults suggested that even when people are physically active for more than 300 minutes per week – double current recommendations – there is still an increased risk of dying associated with prolonged sitting.
This pattern was consistent across sexes, age groups, body mass index categories, and across healthy participants compared to those with pre-existing cardiovascular disease and diabetes. This suggests that sitting is a risk factor independent of physical activity.
While these findings may sound shocking, it’s worth pointing out that such results can easily be misconstrued. For example a review of Australian newspaper articles published between 2000 and 2012 featuring sedentary behaviour (too much sitting) were examined to determine how physical activity was framed. Of the 36 articles that mentioned physical activity, 39% suggested the benefits of physical activity are undone by too much sitting.
Such messages are likely to produce a “what’s the point of trying?” response in many people and so could actually have a negative influence on physical activity behaviour.
What you can do?
It’s important to point out then that evidence indicating too much sitting is bad, is not the same as suggesting that physical activity is not beneficial. On the contrary, a meta-analysis of 16 studies recently found that higher levels of physical activity – 60-75 minutes per day – eliminated the increased risk of death associated with high sitting time. Current UK guidelines recommend 150 minutes of activity per week, usually interpreted as 30 minutes on five days each week.
The message then is clear, meet physical activity guidelines and break up long periods of sitting. To do this, you might need to make some lifestyle changes. You can start by walking or cycling to work – to make your commute active. When you’re at work you also need to have periodic occupational breaks – this could be as simple as standing and walking around. It’s also important to reclaim your lunch break – get outside, go for a walk to increase muscle activity.
Standing or walking meetings can also be a great way to get more movement into your day. As can walking to a colleague’s office to talk rather than emailing. You could also use a height adjustable workstation so you can stand at your desk and move around rather than sit down all day.
Then there’s the simple life hacks like taking the stairs more regularly, and ignoring the lifts. If you’re short on time, perform floor based exercises to break up television watching time, and there’s no reason why you can’t include children in exercise if separate time is challenging.
Decreasing your use of furniture to avoid a passive body position (where your body is fully supported by your a chair), is also good. You don’t have to throw out all your sofa and chairs either – just sitting on the floor can help. You can also use technology to your advantage by using apps to monitor your activity. Even the day to day things like cleaning and tidying help to add movement to your day – and you could try doing these more vigorously.
Of course, not all of these ideas are for everyone. Going furniture-free may seem extreme, but it emphasises the importance of making small changes to alter patterns of energy expenditure. Ultimately, the most important thing is to avoid large chunks of sitting time. So find out what works best for you and try and mix up your movement and activity every day – your body will thank you for it.
Matthew Haines, Acting Head of Division for Sport, Exercise & Nutrition Sciences, University of Huddersfield
Matthew Haines does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.