The Deadly Effects of Prolonged Sitting
Let’s face it, humans are simply not physically designed to sit for prolonged periods of time staring at a computer monitor all day long and moving only selected muscles in the forearms and hands to key in data and maneuver a mouse. Human beings are basically designed to move, much like our great, great ancestors did in the hunter / gatherer days of long ago when we had to be much more physically active to hunt for food and just survive. Office workers just simply do not move enough. Although the computer, along with other advanced technologies, have made our lives easier, they have done so, unfortunately, at great expense to our health. If you work at a computer several hours per day, it is likely, at one time or another, that you have experienced discomfort in different areas of your body such as your neck, back, shoulders, arms, wrists and hands from risk factors associated with poor posture, repetition and contact stress. However, medical research clearly shows that prolonged sitting can lead to more serious health problems that can even shorten your life span.
The harm of excess sitting has been highlighted in articles published by Mayo Clinic Proceedings. Kulinski et al1 linked low physical fitness with being sedentary, while Shuval et al2 went a step further; in their longitudinal analyses, and found that being sedentary increased cardiometabolic risk. Excessive sitting has insidiously swept through society so that chair addiction has become a hallmark of a modern lifestyle. Sitting kills more people than smoking because more people sit excessively than smoke, and the health sequelae of sitting are more numerous.3 The data from these reports added to a growing body of scientific evidence that excess sitting is lethal.3, 4 In fact. excessive sitting has been linked to more than two dozen chronic diseases and conditions including cardiovascular disease, diabetes mellitus, obesity, hypertension, hyperlipidemia, back pain, ankle swelling, and deep vein thrombosis.5 This is particularly troublesome when one takes into account the impact of Covid-19 forcing many American to be imprisoned in their homes working seated in a makeshift office and/or sitting all day watching television and playing computer games. Mix in stress-related over eating, and you have a formula for a catastrophic health crisis unrelated to the actual viral infection.
So how did prolonged sitting and being sedentary come into being? The earliest humans left the forests of Africa on foot but the Industrial Revolution, 200 years ago, precipitated urbanization, the greatest shift in human “lifestyle” since our cave dwelling days. In 1900, less than 10% of the world’s population lived in cities; now more than a half of the world’s population is city based. The Industrial Revolution caused a transition of people working in agricultural communities to sedentary factory-dense cities.9 The event of computerization that included portable computers called cell phones and robotics then enslaved humans to work with electronic devices.
Once the Industrial Revolution took hold, lethal sitting became inevitable. In the 1800s, factory production lines were invented to diminish the need for a worker to waste time walking.9 Soon after that, modern offices were developed with the premise that the fewer minutes workers moved during the workday, the less time was wasted. Workplace automation and mechanization followed with the introduction of typewriters, Dictaphones, intercoms, and adding machines—all of which diminished movement. By the 1950s, mass-produced and affordable cars came onto the market and people replaced walking to work with driving to work. Last came desk-based computerization and the conversion of active play to electronic play.
One obvious consequence of chair-based living is that sitters expend fewer calories than do movers. Compared with recumbent rest, sitting increases the metabolic rate 5%, whereas walking, even at 1 mph, increases energy expenditure 100%.12 A work meeting held at a strolling pace expends 150 to 200 kcal more, per attendee, than does a similar meeting held with the attendees sitting in chairs. Sitting expends almost as few calories as sleeping.
If people who sat more and ate less, body weight might remain stable. But people who sit more do not typically cut their calorie intake appropriately. Over the last 2 centuries, per capita energy intake has not decreased.13 Modern people burn far fewer calories and fail to curb their intake; as a consequence, they eat more calories than they expend. Is it a surprise obesity has become pandemic?
Because modern people are surrounded by chairs—3-legged, 4-legged, wheeled, office chairs, theater chairs, sofas, and car seats—why doesn’t everyone have obesity? Lean people must have a secret. To uncover the secret goings-on of the lean, modern office workers donned underwear interlaced with various body posture and movements sensors.14 The underwear revealed the secret of leanness: People who are lean have high non-exercise activity thermogenesis (NEAT).
NEAT is the energy a person expends in his or her daily life: the calories expended before, during, and after work and while at leisure. Because most people do not indulge in purposeful exercise, NEAT represents the most promising component of human energy expenditure that can be altered. In high-income countries, people sit for most waking hours and have low NEAT. People who are lean have high NEAT, despite the allure of prolonged sitting, are up and strolling 2 ¼ hours per day more than do people with obesity. Lean employees are found to burn on average an extra 350 kcal per day of NEAT which is a powerful engine to stave off obesity.15
Why do people with obesity have low NEAT and how is NEAT regulated? NEAT and its antithesis, sedentariness, are to a degree biologically controlled by genetics. This implies that some people may be biologically prone to keep moving whereas others are born to sit. Watch any group of people: some will fidget and appear restless, whereas others sit still.17
Although biology is likely to be important in determining whether a person is a sitter or a mover, environmental stimuli are likely to be more important. For office workers, modern offices obligate people to sit for most work in front of computers. Also, many major cities necessitate people to use cars rather than walk. If chair-based environments stack the cards against even the best biology, is there any hope? Can we make NEAT-styled living more normative?
There are solutions that work to prevent sedentariness. Offices can incentivize protocols for walking meetings, incentivize leg-based interactions (e.g., walk across the office versus e-mail), and install walking tracks or treadmill desks. Sit/stand desks, when used correctly, can offer the ability to burn more calories while working during standing. Active offices not only report improved health but less perceived stress and improved productivity.20 Improve the environment to promote physical activity. Having well lit, bright, clean, attractive stairwells with visible prompts can promote walking up steps better than do poorly lighted, dirty, dank ones.21 Provide incentives for joining fitness clubs and provide healthy food options in the work area. Stop providing donuts and other processed carbs at meetings that induce sleepiness and lethargy. Periodically organize motivational speakers that address becoming physically fit.
In summary, employers need to understand the health consequences of prolonged sitting, seriously analyze how much time their employee are required to sit during the work day, and determine methods to reduce that time and incorporate with more energy burning activities
References
- Kulinski, et al, Association between cardiorespiratory fitness and accelerometer-derived physical activity and sedentary time in the general population. Mayo Clin Proc. 2014; 89: 1063-1071
- Shuval, et al, Sedentary behavior, cardiorespiratory fitness, physical activity, and cardiometabolic risk in men: The Cooper Center Longitudinal Study. Mayo Clin Proc. 2014; 89: 1052-1062
- Dunstan, et al, Too much sitting–a health hazard. Diabetes Res Clin Pract. 2012; 97: 368-376
- Ford, et al, Sedentary behavior and cardiovascular disease: a review of prospective studies. Int J Epidemiol. 2012; 41: 1338-1353
- Wilmot, et al, Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis. Diabetologia. 2012; 55: 2895-2905
- Lordkipanidze, et al, A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo. Science. 2013; 342: 326-331
- Crompton, et al, Locomotion and posture from the common hominoid ancestor to fully modern hominins, with special reference to the last common panin/hominin ancestor. J Anat. 2008; 212: 501-543
- Rosenbaum, et al, D Cognition, action, and object manipulation. Psychol Bull. 2012; 138: 924-946
- Cowan R.S., The “Industrial Revolution” in the home: household technology and social change in the 20th century. Technol Cult. 1976; 17: 1-23
- Levine, et al, Non-exercise physical activity in agricultural and urban people. Urban Stud. 2011; 48: 2417-2427
- Ergotron Inc. Sitting so much should scare you. http://www.juststand.org/tabid/800/language/en-US/default.aspx. Accessed June 5, 2014.
- Levine, et al, Energy expenditure of non-exercise activity. Am J Clin Nutr. 2000; 72: 1451-1454
- James W.P., The epidemiology of obesity. Ciba Found Symp. 1996; 201 (discussion 11-16, 32-36): 1-11
- Levine, et al, Interindividual variation in posture allocation: possible role in human obesity. Science. 2005; 307: 584-586
- Levine, et al, Role of non-exercise activity thermogenesis in resistance to fat gain in humans. Science. 1999; 283: 212-214
- Teske, et al, Neuropeptidergic mediators of spontaneous physical activity and non-exercise activity thermogenesis. Neuroendocrinology. 2008; 87: 71-90
- Novak, et al, Central neural and endocrine mechanisms of non-exercise activity thermogenesis and their potential impact on obesity. J Neuroendocrinol. 2007; 19: 923-940
- Hill, et al, Environmental contributions to the obesity epidemic. Science. 1998; 280: 1371-1374
- Levine, et al, Poverty and obesity in the U.S., Diabetes. 2011; 60: 2667-2668
- Ben-Ner, et al, Treadmill workstations: the effects of walking while working on physical activity and work performance. PLoS One. 2014; 9: e88620
- Ruff, et al, Associations between building design, point-of-decision stair prompts, and stair use in urban worksites. Prev Med. 2014; 60: 60-64
- Maizlish, et al, Health co-benefits and transportation-related reductions in greenhouse gas emissions in the San Francisco Bay area. Am J Public Health. 2013; 103: 703-709