The dangers of sitting on our hands

Research appearing today in the journal Diabetologia suggests that sitting down for protracted lengths of time can increase your risk of developing diabetes, cardiovascular disease and even death.

The collaborative study by researchers at the University of Leicester, Loughborough University and the NIHR Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit (BRU) shows that sedentary behaviour can compromise health even when the daily guidelines for levels of physical activity are met.

Dr Emma Wilmot, a research fellow in the Diabetes Research Group at the University of Leicester and Clinical Research Fellow in the Leicester Diabetes Centre at Leicester General Hospital, told ScienceOmega.com that many of the 18 studies whose results were combined to provide data for the study were large. Altogether, 794,577 participants were included in the meta-analysis.

"We identified studies which specifically measured behaviours which involve sitting down," Dr Wilmot explained. "The term ‘sedentary’ has previously been used to infer a lack of exercise. However, there is now a wealth of evidence to support an association between excess sitting time and adverse health outcomes, even if individuals perform adequate amounts of physical activity.

"We included cross-sectional and prospective studies from around the world which reported data on the amount of time spent in sedentary behaviours such as self-reported sitting time or television viewing."

The researchers found a strong correlation: people who sit for prolonged periods increase their risk of diabetes, heart disease and death two-fold. Dr Wilmot described how the authors of the paper have been aware of the importance of excess sitting and the negative impact on health for some time.

"This is why we felt it was important to summarise the available data and increases awareness of the dangers of sitting for long periods," she said. "The evidence for the hazards of excess sitting has been building for some time now and it is important that this message is now communicated to the public."

Given that between 50 and 70 per cent of the average adult’s time is spent sitting, the subsequent impact on public health is bound to be considerable. Moreover, adjusting the results for the amount of physical activity undertaken did not change the association between sitting and diabetes or cardiovascular mortality, a finding which makes sense according to Dr Wilmot.

"Even if someone meets the physical activity recommendations of 30 minutes of exercise a day, what they do with the remaining 23.5 hours is bound to have influence over health. In modern society it is easy to spend most of the day sitting at a computer. To think that a 30 minute burst of exercise could compensate for sitting still for the rest of the day is optimistic.

"That said, there is an immense amount of research to support the importance of physical activity for health; someone who sits all day and does some exercise is still less likely to develop health complications such as diabetes than someone who sits all day and does no exercise."

The findings of the analysis could be particularly relevant for those who already have a higher risk of developing diabetes, such as individuals with a family history of the disease, the obese, and those of South East Asian origin. In these cases it may prove especially beneficial to find ways to limit the amount of time spent sitting.

Co-investigator Professor Melanie Davies, also from the University of Leicester, has been motivated by her insight into the potential risks to invest in ‘standing desks’ for the diabetes researchers on her team, allowing them to stand while working on their computers.

With such a large proportion of us working on computers and reliant on sitting at a desk for most of the day, I asked Dr Wilmot what strategies – other than standing desks – individuals and organisations could put in place to alleviate the risks presented by prolonged sitting.

"We have recently recruited 193 young adults who are at risk of diabetes for the STAND (Sedentary Time And Diabetes) study which aims to reduce sitting time by one hour a day," she replied. "In the education classes we ran with these individuals there were many suggestions to reduce sitting time such as moving the waste bin so you need to get out of your chair to reach it, standing for a coffee rather than taking it back to your desk, ironing while watching television, reading or working on the computer whilst standing, and standing on the train to name a few."

Dr Wilmot emphasised that what emerged from these sessions was that, although there are many methods to help reduce sitting time, solutions really need to be tailored to each individual if they are to be effective.

"At the moment there is not enough evidence to suggest exactly how much we need to reduce our sitting time by, but we hope that the results of the STAND randomised controlled trial – due to report next year – will bring us a step closer to some detailed recommendations on this subject."