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Sitting Ducks – Sedentary Behaviour and its Health Risks: Part One of a Two Part Series

21 Jan, 15 | by BJSM

Undergraduate perspective on Sports & Exercise Medicine – a BJSM blog series

By Rory Heath (@Roryjheath)

The recent Inaugural Active Working Summit, January 8th, 2015, brought together representatives from healthcare, scientific research and commercial organisations with an aim to promote wellness at work.

At BJSM, we’ve covered the benefits of exercise on the brain before and even proposed a ‘Tour de Office’. Here, we profile a great example of progress in the field, demonstrating the latest research into problems and their solutions.

I will present the Summit’s findings as part of a two part series: 1. Sedentary Behaviour & its Health Risks and; 2. Implementation of Active Working  and related workplace behaviours changes.

Setting the Scene – How Much Time Do We Sit? Changing Patterns of Sedentary Behaviour. Dr Stacy Clemes, Senior Lecturer in Human Biology, Loughborough University

  • During waking hours 65% of an average person’s day is spent sedentary; 9-10 hours for adults.
  • Sitting at work = 60% of total daily sitting time on a weekday, but even on weekends people still sit for 8 hours.
    – Activity at work can have great effect to reduce sedentary behaviour time!
  • High work sitters spent >7.5 hours sitting at work.
    – How many hours does a typical medical student spend sitting down in preclinical?
  • Even in the ‘active’ education and retail sectors, employees spend >6 and 2 hours respectively sitting at work, with 10 and 6 hours totally spent sitting over the day. Employees in Telecommunications spend >12 hours sitting a day!
  • More sedentary at work = more sedentary at home. Unfortunately, these people do not tend to compensate by increasing activity in their leisure time. (Clemes et al., 2015)

Why Sitting is Bad – Effects on Heart Disease, Obesity and Diabetes.
Dr Jason Gill, Reader, Institute of Cardiovascular and Medical Sciences, University of Glasgow

  • Even if a person completes the recommended daily 30 minutes of exercise, the amount of time spent sitting in the day still substantially affects mortality risk.
  • Diabetes; A major cause of blindness, amputation and mortality. NHS diabetes spending is projected to double to £16.9 billion by 2035 (see here).
  • People that sit the most have a 112% increase in the Relative Risk (RR) of Diabetes and a 147% increase in the RR of cardiovascular events compared to people who sit down the least. Overall mortality is increased by 50%. Sitting down has similar mortality rates to smoking (Wilmot et al, 2012, Diabetologia)
  • It’s been shown that prolonged sitting adversely affects glucose metabolism. However, sitting with ‘light-moderate’ intensity breaks can significantly reduce glucose and insulin levels.

Sedentary Behaviour and Risk Co-Relation to Cancer and Mental Health.
Dr David Dunstan, Professor & Head, Physical Activity Laboratory, Baker IDI –

Positive associations between Cancer and Sedentary Behaviour exist:
– Lung cancer increases by 54%
– Uterine cancer 66%
– Colon Cancer 30% increased risk.

Despite these associations, there is a lack of high quality studies. ‘We may see stronger relationships between sedentary behaviour and cancers if we measured it better’.

  • Potential mechanisms – Sedentary behaviour contributes to an interrelated network of increased body fat, altered production of sex hormones, metabolic dysfunction, leptin, adiponectin and inflammation, encouraging cancer development.

Mental health

The risk of anxiety and depression is significantly higher in those who sit more while increased activity shows better subjective mental heath and vitality.
Potential mechanism: Physical activity displaces sedentary behaviour and has proven benefits. Perhaps there is also a ‘social withdrawal hypothesis involvement’.

  • Sitting has a higher rate of subjective fatigue than standing.

A Brief Overview of Global Sedentary Science Research.
Dr Sebastien Chastin, Senior Research Fellow in Behaviour Dynamics, Glasgow Caledonian University

  • 1953 ‘London Bus Study’ – bus drivers had a higher mortality rate due to Cardiovascular Disease compared to the more active bus conductors. If a conductor’s ‘Low level activity’ is beneficial, this should translate similar benefits in our modern world. (J Morris et al., 1953)
  • Start Active, Stay Active states that all ages should ‘minimise the amount of time spent being sedentary for extended periods’. It’s now time to convert studies and new policy into change and progress in the workplace.
  • For every €100 spent on Nutrition, €35 is spent on Physical Activity but only €6 Euros are spent on Sedentary Behaviour research ➔ more funding is needed.

The Sitting Time Bomb – Are We Prepared?
Dr Tom Yates, Senior Lecturer in Physical Activity, Sedentary Behaviour & Health, Diabetes Research Centre, University of Leicester

  • We are now victims of our own environment. Historically human mortality was due to infective causes; now our greatest killers are self-inflicted Physical Inactivity, Smoking, Diabetes and CVD.
  • We spend £8 billion on T2D, 14 billion on CVD and 9 billion on cancer. These are preventable – it is the interaction of our genes and our environment that is causing these diseases.
  • The classic medical solution is to provide a pill:
    Pharmaceutical companies spend between $873 million to $8 billion in drug development. This completely dwarfs the money spent on research into sedentary behaviour.
  • We treat obesity through invasive, dangerous surgery. We must find a preventative, cheaper, safer option; through changes to environment and policy. It is possible – look at the change in smoking.

Takeaway thoughts

Public Health focuses on promoting Exercise but neglects sitting, where people spend the majority of their time. There is a grey area between moderate and sedentary activity that needs to be addressed in public health policy.

  • You can still be active whilst sitting. Fidgeting and moving around can reduce time spent sitting still. Choose your office furniture wisely, choose ergonomic chairs and sit-stand desks.
    ‘Just moving around will lead to benefits’.
  • We urgently need large scale long term intervention studies to evaluate effect of interventions to reducing sitting on health outcomes in real world settings.

#ActiveWorking is gaining momentum and will continue to change workplaces in the future. To see tweets from myself and others from the event, enter #ActiveWorking on Twitter. To find out more about the event, check out (@getGBstanding) and (@ACTIVEworking), and subscribe to hear the latest details of next year’s event.

In the meantime; stand, walk, fidget and move as much as you can before the second blog is posted!

Rory Heath (@roryjheath) is a third year medical student at King’s College London (KCL) and has a keen interest in sport, diet and exercise. He has played county rugby and rugby league for London and South. He is currently the KCL representative of the undergraduate London Sport & Exercise Medicine Society (LSEMS). ( He runs a blog at

Dr. Liam West BSc (Hons) MBBCh PGCert SEM (@Liam_West) is a Cardiff Medical School graduate and now a junior doctor at the John Radcliffe Hospital, Oxford. He is an Associate Editor for BJSM and also coordinates the “Undergraduate Perspective on Sports & Exercise Medicine” Blog Series.

If you would like to contribute to the “Undergraduate Perspective on Sports & Exercise Medicine” Blog Series please email LIAMWESTSEM@HOTMAIL.CO.UK for further information.

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