Sedentary Behaviour and Health Risks

Introduction:

Are you at risk of sitting disease? Are you an active couch potato? Sitting disease is a term that is becoming more common place in the public eye and in the literature.1 Sitting for more than six hours per day has been reported to be associated with a 40% increase in mortality risk.1 On the other hand, sitting for less than 3 hours per day appears to be associated with improved health outcomes.1 Increasing physical activity is important, however, researchers have also discovered that individuals who may meet the American College of Sports Medicine physical activity guidelines may still be at risk of sitting disease if more than 3 hours per day is spent in sedentary activity such as sitting at the computer.1,2 A growing collective of researchers are studying the physiological effects of sedentary activity and the results are alarming.1, Chronic disease is on the rise with increased incidence of cardiovascular problems, diabetes, arthritis, and mental illness, which are often associated with inactivity and obesity.3  Sedentary work has increased by 50% over the last 50 years contributing to more inactivity in our society.4 There are significant health risks and costs to the already overburdened healthcare system.5  This paper will explore the literature related to sedentary behavior and the physiological effects of such behaviour. Preliminary results associated with costs to the health care system and the work force will be discussed along with strategies to reduce sedentary activity. The treadmill work station, a key strategy, to reduce sitting time will be illustrated with recent findings from the literature.6 Sitting disease has significant health risks with encouraging news that this is a modifiable risk factor.7

What is sedentary behavior and how is this defined? In some of the literature sedentary behaviour has been defined as any activity that is below 1.0 to 1.5 multiples of the basal metabolic rate (METS).4 Activities such as standing are considered light activity behaviours when the energy expenditure is under 2.9 METS .4 Moderate to vigorous physical activity is defined with energy expenditures that range from 3 to 8 METS, which includes such activities as bicycling, swimming, or walking.4  Neville et al. (2010) have found evidence that sustained periods of sitting have biological complications such as a loss of muscular contractions leading to the reduction of skeletal muscle lipoprotein lipase activity and a resultant depression in glucose absorption. The reduction of muscle lipoprotein lipase activity has also been found to result in a decrease in triglyceride uptake and high density lipoprotein (HDL) cholesterol production, which is associated with increased risk of cardiovascular problems.4 The increase in time spent sitting is associated with cardio metabolic dysfunction and authors have discovered that the metabolic problems are not counteracted by meeting physical activity guidelines as outlined by the American Sports Medicine Council.4 From this finding the “couch potato phenomenon” has been coined.4 An individual may be considered healthy by surpassing recommended physical activity guidelines by riding their bike to and from work for 2 hours day but, may still be at risk of “sitting disease” with eight hours of sedentary office activity.4 Encouraging evidence illustrates that metabolic changes, such as an improvement in glucose levels are modified with a reduction in sedentary activity such as standing, changing position from sit to stand or walking slowly.4

As reported sedentary behaviour has negative health consequences providing strong evidence of the importance to reduce time spent in sedentary tasks. Researchers have found that reallocating time spent sitting to light intensity activity, moderate to vigorous activity or sleep time from sedentary time is associated with positive changes in cardiovascular disease risk biomarkers.8 When 30 minutes a day was reallocated from sedentary activity to sleep or other active tasks health markers improved such as lower triglycerides, lower insulin, smaller waist circumference, higher high-density lipoprotein cholesterol, and lower glucose levels.8 The most significant positive changes in cardiovascular disease risk biomarkers were associated with moderate to vigorous activity but, changes were still evident with light activity.8 This research indicates that positive changes in health can be made with small changes in overall physical activity.8

As highlighted, sitting for long durations of greater than 30 minutes are associated with health risks and physiological changes resultant of chronic disease and an overall increase in mortality.1 Cardiovascular health is also significantly impacted by increased sitting time and evidence continues to reveal that sedentary behaviour is associated with weight gain and obesity.9  Metabolic disease and diabetes are other conditions that are more likely to develop with sustained sedentary positions.9 Musculoskeletal dysfunction is also found with increased sitting time resulting from less skeletal muscle activity and joint mobility typically resulting in increased pain, decreased function and weakness.9 In addition to the ill effects associated with the musculoskeletal and cardiovascular systems deleterious effects are found to impact cognitive health.9 A prospective study of sedentary behaviour found that there was an increased risk of depression and cognitive impairment with sitting activity and in particular television watching.10 This study found that not all sedentary activities are the same as sedentary positions with internet use were found to have less negative mental health effects.10 Although, there were less negative effects to cognitive health with internet use the physiological side effects should not ignored.

The health risks of sedentary behaviour have been presented across the ages. In the older age group similar negative side effects have also been discovered. Based on a systematic review by Rezende et al. (2014) of older adults over the age of 60 sedentary behaviour seems to have an even greater impact on all cause mortality than the presence of other chronic conditions such as diabetes.11 A review of the literature reveals that those older adults who did not meet the 150 minutes activity requirement per week and spent greater than 8 hours per day sitting were at a 30% increase in all cause mortality.11 For every hour sitting there was a 3% increase in all cause mortality.11 Evidence was also found that increased sedentary behaviour was associated with higher blood pressure, lower HDL cholesterol profiles, high blood pressure, higher plasma glucose, higher waist circumference and obesity.11   Some articles that did not reveal statistical significance related to the negative effects of sedentary behariour were revealed from the systematic review.11 However, there were a greater number or articles that provided strong statistical evidence of the ill effects of sustained sitting behaviour. The literature revealed that sitting for greater than 4 hours per day appeared to be a tipping point related to negative health outcomes.11

The health risks associated with sedentary activity are clear, and compelling in light of the evidence that increased sitting time regardless of meeting physical activity guidelines is still associated with health risks.10,11 Despite the evidence indicating the health risks with typical sedentary work and leisure activity there is encouraging evidence indicating that a reversal in these health outcomes with the introduction of light physical activity is possible.11 It is encouraging to note that Immediate positive health benefits were found with a decrease in sitting time and strategies to improve activity levels will be discussed shortly. 4

In addition to the many negative health effects related to sedentary behaviour there are significant health care costs. Chronic disease such as heart disease, stroke, cancer, respiratory diseases and diabetes are among the leading causes of death in the world representing 63% of all deaths worldwide.12 In Canada the management of chronic disease is presenting a significant challenge for the medical system with osteoporosis, diabetes, high blood pressure, cancer and depression being among the most common conditions.12  It is estimated that one third of all Canadians will develop one chronic health condition in their life time.13   Heart disease, stroke, type 2 diabetes, and more than one third of all cancers can be prevented by changing behaviours related to activity, diet, alcohol use and smoking.14 Chronic disease is common in our population and impacts 67% of the Canadian health care budget with direct costs. Indirect costs of $52 billion were estimated due to premature death and loss of productivity.12

As more evidence is revealing health risks associated with sedentary behaviour it is important to give attention to strategies to increase activity and improve the overall health of our society.1 There are many positive effects associated with walking related to increased muscle activation, balance, and improved cardiovascular health.14  With the work force spending more time in sitting and the retirement age extended in many countries to 65+ years of age it is key to advocate for change in how work is conducted. There is a growing body of research lead by James Levine related to the benefits of walking and the use of the treadmill work stations whereby office work is conducted while walking at a slow pace.6 The health benefits related to walking are clear.6 15 However, can individuals still deliver a high level of work productivity when walking? A study conducted by Ben Ner et al. (2014) discovered that the use of treadmill workstations had a positive impact on physical activity and work performance. This study revealed that with the availability of treadmill work stations individuals had 77 fewer minutes of sedentary behviour. Although, there was an initial decline in work performance adjusting to the use of the new treadmill work station, work quantity improved overall and reached a peak at the 18 week mark.6

One strategy to decrease sedentary beahviour with the use of treadmill work stations appears beneficial. As Dr. Genevieve Healy (2013) has found in her research successful strategies for change include a multifactorial approach. Other successful strategies for change include moving printers further away from work stations, incorporating walking meetings and the use of mobile applications that provide reminders to move throughout the work day.16  Education and the involvement of individuals to determine factors for change have been identified as key components to promote successful change.16 Visual reminders and accountability with health consultants and managers are other supports that appear to improve levels of success in implementing work related programs to decrease sedentary behavior.16 A multi faceted approach to promote change is important which has been confirmed by researchers in the nursing field in Scotland.17 To successfully promote physical activity a combination of approaches are necessary which may include medical, education, client centred, societal change and targeted campagins.17   Addressing sedentary behaviour is important to mitigate the risks of chronic disease in our society.

Consider the above information, are you at risk of sitting disease? Sedentary behaviour is common among people in our society and the negative health impacts are more prevalent with an increase in chronic disease and an overall increase in mortality.1 High blood pressure, low HDL levels, high plasma glucose, increased waist hip ratios, joint stiffness, and muscle weakness are among some of the negative health factors that are associated with sedentary behaviour.3 If sustained periods of sitting are maintained throughout the day the negative health effects are still prevalent even among those individuals that engage in the recommended physical activity doses.3 The literature is clear that moving throughout the day is important to improve overall health.1,3,4 One strategy to foster this change is with the use of a treadmill work station. This is one tool and it is apparent that multiple strategies are important to foster changes in sedentary behaviour.6   The negative impact of sedentary behviour on our health is evident and the time is now to implement change to improve the overall health of our society.

 

References:

  1. Patel et al. Leisure time spent in sitting in relation to total mortality in a prospective cohort of US adults. American Journal of Epidemiology. 2010; Vol 172,No 4.
  2. Ewing, Carol et. al. Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory, Musculoskeletal, and Neuromotor Fitness in Apparently Healthy Adults: Guidance for Prescribing Exercise. Medicine and Science in Sports and Exercise. 2011. 1335-1359.
  3. Owen N, Bauman A, Brown W. Too much sitting: a novel and important predictor of chronic disease risk? Br J Sports Med. 2009; 43(2):81–3.[PubMed]
  4. Owen, Neville et al. Too much sitting: the population-health science of sedentary behaviour. Exercise Sport Science Review. July 2010; 38(3):105-113.
  5. Healy et al. 2012 Vic Health
  6. Ben Ner et al. Treadmill workstations: the effects of walking while working on physical activity and work performance. PLOS One. 2014; Vol 9,2, 2014.
  7. Barnes, Smith. Emerging modifiable risk factors for cardiovascular disease in women, Obesity, physical activity and sedentary behaviour. Texas Heart Institute Journal. 2013; 40(3): 293-295.
  8. Burman et al. Reallocating time to sleep, sedentary behaviors, or active behaviors: associations with cardiovascular disease risk biomarkers. NHANES. 2006.
  9. Tremblay et. al. Physiological and health implications of a sedentary lifestyle. Physiol. Nutr. Metab. 2010; 35:725-740.
  10. Hamer, Mark; Stamatakis, Emmanuel. Prospective study of sedentary behavior, risk of depression, and cognitive impairment. Medicine and science and sports and exercise. 2014; Vol 46 (4), 718-723.
  11. Rezende et al. Sedentary behavior and health outcomes among older adults: a systematic review. BMC Public Health. 14: 333.
  12. Chronic disease prevention and management. Available at: http://www.nurseone.ca/Default.aspx?portlet=StaticHtmlViewerPortlet&&ptnme=NurseONE%20Knowledge%20-%20Chronic%20Disease. Accessed May 24, 2014.
  13. Health council of Canada. A health outcomes report: Why health care renewal matters: Learning from Canadians with chronic health conditions. Health council of Canada report. 2007. Availabe at: lhttp://www.healthcouncilcanada.ca/tree/2.20-Outcomes2FINAL.pdf
  14. Chronic disease management. International council of nurses. Available at: http://www.icn.ch/publications/publications1/. Accessed May 25, 2014.
  15. Nelson, Miriam and Folta, Sara. Further evidence for the benefits of walking. The American journal of clinical nutrition. 2009. Vol 89, 115-116.
  16. Neuhaus M., Healy G.N, Fjeldsoe B.S, Lawier S., Owen N., Dunstan D.W, LaMontagne A.D. and Fakin E.G. Iterative development of stand up Australia: a multi-component intervention to reduce workplace sitting. International journal of behavioral nutrition and physical activity. 2014: 11, 1.
  17. Morton, K. Implementing evidence-based health promotion strategies. Nursing standard. 2013: 27, 35-42.

 

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>