Advertisement
Mayo Clinic Proceedings Home

The Chairman’s Curse: Lethal Sitting

  • James A. Levine
    Correspondence
    Correspondence: Address to James A. Levine, MD, PhD, Division of Endocrinology, Mayo Clinic in Arizona, 13400 East Shea Blvd, Scottsdale, AZ 85259.
    Affiliations
    Division of Endocrinology, Mayo Clinic in Arizona, Scottsdale, AZ
    Mayo Clinic/Arizona State University Obesity Solutions Initiative, Tempe, AZ
    Search for articles by this author
      The harm of excess sitting is highlighted in 2 articles published in this issue of Mayo Clinic Proceedings. Kulinski et al
      • Kulinski J.P.
      • Khera A.
      • Ayers C.R.
      • et al.
      Association between cardiorespiratory fitness and accelerometer-derived physical activity and sedentary time in the general population.
      link low physical fitness with sedentariness even when exercise participation is accounted for, while Shuval et al
      • Shuval K.
      • Finley C.E.
      • Barlow C.E.
      • et al.
      Sedentary behavior, cardiorespiratory fitness, physical activity, and cardiometabolic risk in men: the Cooper Center Longitudinal Study.
      go a step further; in their longitudinal analyses, sedentariness is shown to ultimately predict cardiometabolic risk. The data from these 2 reports add to a growing body of scientific evidence that excess sitting is lethal.
      • Dunstan D.W.
      • Howard B.
      • Healy G.N.
      • Owen N.
      Too much sitting–a health hazard.
      • Ford E.S.
      • Caspersen C.J.
      Sedentary behaviour and cardiovascular disease: a review of prospective studies.
      Excessive sitting has been linked to more than 2 dozen chronic diseases and conditions including cardiovascular disease, diabetes mellitus, obesity, hypertension, hyperlipidemia, back pain, ankle swelling, and deep vein thrombosis.
      • Wilmot E.G.
      • Edwardson C.L.
      • Achana F.A.
      • et al.
      Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis.
      Of concern, going to the gymnasium after work does not offset the harm of sitting, and excess sitting harms lean and obese people alike.
      • Dunstan D.W.
      • Howard B.
      • Healy G.N.
      • Owen N.
      Too much sitting–a health hazard.
      Studies, thousands of them, drill down to the same point: sitting is lethal.
      Some Americans sit for 13 h/d. How can something that we do so much be so dangerous—it seems implausible? But there are other life functions that have proven harmful. For example, take eating: We eat several times every day but do not need convincing as to how harmful eating has become. Eating, like sitting, is life-threatening when done in excess. Environmental design can affect every breath one takes: Consider the plight of an asthmatic on a high smog day in Los Angeles. Even breathing can be dangerous in an injurious environment.
      How did global chair seduction come into being without us noticing? The earliest humans, Homo, left the forests of Africa on foot. The fossilized Dmanisi skulls found in the republic of Georgia
      • Lordkipanidze D.
      • Ponce de León
      • Margvelashvili A.
      • et al.
      A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo.
      showed that early Homo walked upright. Over 2 million years, progressive human upgrades evolved and these involved increasing the complexity of their brains, walking more progressively erect, and being active for most of the day.
      • Crompton R.H.
      • Vereecke E.E.
      • Thorpe S.K.
      Locomotion and posture from the common hominoid ancestor to fully modern hominins, with special reference to the last common panin/hominin ancestor.
      The earliest and most profound inventions—fire, the wheel, bridge building, warfare techniques, fortification, hunting, and agriculture—were all borne from active minds, hands, and bodies.
      • Rosenbaum D.A.
      • Chapman K.M.
      • Weigelt M.
      • Weiss D.J.
      • van der Wel R.
      Cognition, action, and object manipulation.
      The Industrial Revolution, 200 years ago, precipitated that greatest shift in human “lifestyle” since our evolution: urbanization. In 1900, less than 10% of the world’s population lived in cities; now more than half of the world’s population is city based. The Industrial Revolution seduced people from agricultural communities to sedentary factory-dense cities.
      • Cowan R.S.
      The “Industrial Revolution” in the home: household technology and social change in the 20th century.
      Modernity then stripped people of free thinking to become enslaved by 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.
      • Cowan R.S.
      The “Industrial Revolution” in the home: household technology and social change in the 20th century.
      Soon after that, modern offices were developed with the premise that the fewer minutes workers moved during the workday, the less time was wasted. The 1930s saw the rise of the archenemy—the office chair. 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 forewent walking to work and drove. Last came desk-based computerization and the conversion of active play to electronic play. It took nature 2 million years to design the walking, dynamic human, and it took those humans 200 years to reverse the art of nature and cram people all day long into chairs. And so, insidiously, the Chairman—the secretive seated overseer—had won.
      The physiological impact of converting a traditional ambulatory way of life to a chair-sentenced one is demonstrated by studies in agricultural communities. In Jamaica, for instance, people living in agricultural communities sit half as much as weight-matched people living in urban Kingston.
      • Levine J.A.
      • McCrady S.K.
      • Boyne S.
      • Smith J.
      • Cargill K.
      • Forrester T.
      Non-exercise physical activity in agricultural and urban people.
      Interestingly, urban Kingston dwellers have similar sitting habits as do urban North Americans. Jamaicans living in agriculture communities sit for about 3 hours each day, whereas an average American worker can clock 13 hours of sitting.

      Ergotron Inc. Sitting so much should scare you. http://www.juststand.org/tabid/800/language/en-US/default.aspx. Accessed June 5, 2014.

      The chair sentence is a mantle of modernity.
      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%.
      • Levine J.A.
      • Schleusner S.J.
      • Jensen M.D.
      Energy expenditure of nonexercise activity.
      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 ate less, body weight might remain stable. But people who sit more do not cut their calorie intake appropriately. Over the last 2 centuries, per capita energy intake has not decreased.
      • James W.P.
      The epidemiology of obesity.
      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 that Homo sedentarius has obesity?
      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.
      • Levine J.A.
      • Lanningham-Foster L.M.
      • McCrady S.K.
      • et al.
      Interindividual variation in posture allocation: possible role in human obesity.
      The underwear revealed the secret of leanness: People who are lean have high nonexercise 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 chairdom; they are up and strolling 2 ¼ h/d more than do people with obesity. The lean burn an extra 350 kcal/d of NEAT; it is a powerful engine to stave off obesity.
      • Levine J.A.
      • Eberhardt N.L.
      • Jensen M.D.
      Role of nonexercise activity thermogenesis in resistance to fat gain in humans.
      How is NEAT regulated? Why do people with obesity have low NEAT? NEAT and its antithesis, sedentariness, are to a degree biologically controlled. Animal studies demonstrate a complex integrated neural circuitry that drives an animal to increase NEAT or become sedentary. One key neural control center is in the paraventricular nucleus of the hypothalamus. Here, neural mediators such as orexin and neuromedin U activate movement.
      • Teske J.A.
      • Billington C.J.
      • Kotz C.M.
      Neuropeptidergic mediators of spontaneous physical activity and non-exercise activity thermogenesis.
      The potency of these signals is enhanced in animals inbred for leanness. Animals inbred for sedentariness and obesity are less responsive to NEAT signals. In human terms, 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.
      • Novak C.M.
      • Levine J.A.
      Central neural and endocrine mechanisms of non-exercise activity thermogenesis and their potential impact on obesity.
      Biology is likely to be important in determining whether a person is a sitter or a mover. However, environmental stimuli are likely to be more important.
      Environmental cues are the predominant determinants of sedentariness.
      • Hill J.O.
      • Peters J.C.
      Environmental contributions to the obesity epidemic.
      The human genome has not substantially changed in 200 years, but over that time the humans’ default posture has changed from ambulatory to chair-based. Urban society/environment must be to blame. In the United States, a person’s postal code is a key predictor of sedentariness.
      • Levine J.A.
      Poverty and obesity in the U.S.
      More specifically, people who live in poverty-dense regions are more likely to be sedentary, and to have diabetes mellitus and obesity, than do people living in wealthier areas. Because poverty is not a personal choice and a person’s postal code is not genetically predetermined, societal determinants of sedentariness must override biological forces. For office workers, for instance, modern offices obligate people to sit for most work in front of computers. Also, many major cities, such as Los Angeles, necessitate people to use cars rather than walk. Other societal-environmental predictors of sedentariness include the weather, outdoor safety, domestic violence, and the proximity of homes to parks.
      • Hill J.O.
      • Peters J.C.
      Environmental contributions to the obesity epidemic.
      If chair-based environments stack the cards against even the best biology, is there any hope? Is Homo sedentariness doomed to die from lethal sitting? Outcome-based approaches exist to help people break free of their chairs and get up. The brain responds to move-it stimuli both structurally and biochemically, much like a muscle does. NEAT begets NEAT.
      Office, school, home, and even street design can be modified so that NEAT-styled living becomes normative. Offices can incentivize protocols for walking meetings, incentivize leg-based interactions (eg, walk across the office versus e-mail), and install walking tracks or treadmill desks. Active offices not only report improved health but less perceived stress and improved productivity.
      • Ben-Ner A.
      • Hamann D.J.
      • Koepp G.
      • Manohar C.U.
      • Levine J.
      Treadmill workstations: the effects of walking while working on physical activity and work performance.
      Schools can be designed to promote active learning, and research demonstrates improvement to health, attentiveness, and educational outcomes. Bright, clean, attractive stairwells with visible prompts promote walking up steps better than do poorly lighted, dirty, dank ones.
      • Ruff R.R.
      • Rosenblum R.
      • Fischer S.
      • Meghani H.
      • Adamic J.
      • Lee K.K.
      Associations between building design, point-of-decision stair prompts, and stair use in urban worksites.
      The potential health benefits for active cities are great. For San Francisco in 2013, the average person’s travel time by foot was 4 min/d. In a leg-based travel-active scenario, average commutes would increase by 18 minutes. The health benefits would be a potential 2404 avoided premature deaths per year. This degree of improved health would rank among the greatest health advances in modern history,
      • Maizlish N.
      • Woodcock J.
      • Co S.
      • Ostro B.
      • Fanai A.
      • Fairley D.
      Health cobenefits and transportation-related reductions in greenhouse gas emissions in the San Francisco Bay area.
      and health care cost savings in San Francisco would approximate $34 billion/y. Tested solutions exist to combat sedentariness and thwart the Chairman.
      Excessive sitting has insidiously swept through society so that chair addiction has become a hallmark of modernity. The 2 articles in this edition of the Mayo Clinic Proceedings, coupled to a wealth of other data, underscore the harmfulness of the chair. Sitting kills more people than smoking because more people sit excessively than smoke, and the health sequelae of sitting are more numerous.
      • Dunstan D.W.
      • Howard B.
      • Healy G.N.
      • Owen N.
      Too much sitting–a health hazard.
      There are solutions that work to prevent sedentariness, but the challenge of remediation is broad and profound. Will we forsake our legs and let the Chairman win; or will we act? Take a stand and get up!

      References

        • Kulinski J.P.
        • Khera A.
        • Ayers C.R.
        • 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 K.
        • Finley C.E.
        • Barlow C.E.
        • 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 D.W.
        • Howard B.
        • Healy G.N.
        • Owen N.
        Too much sitting–a health hazard.
        Diabetes Res Clin Pract. 2012; 97: 368-376
        • Ford E.S.
        • Caspersen C.J.
        Sedentary behaviour and cardiovascular disease: a review of prospective studies.
        Int J Epidemiol. 2012; 41: 1338-1353
        • Wilmot E.G.
        • Edwardson C.L.
        • Achana F.A.
        • 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 D.
        • Ponce de León
        • Margvelashvili A.
        • et al.
        A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo.
        Science. 2013; 342: 326-331
        • Crompton R.H.
        • Vereecke E.E.
        • Thorpe S.K.
        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 D.A.
        • Chapman K.M.
        • Weigelt M.
        • Weiss D.J.
        • van der Wel R.
        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 J.A.
        • McCrady S.K.
        • Boyne S.
        • Smith J.
        • Cargill K.
        • Forrester T.
        Non-exercise physical activity in agricultural and urban people.
        Urban Stud. 2011; 48: 2417-2427
      1. Ergotron Inc. Sitting so much should scare you. http://www.juststand.org/tabid/800/language/en-US/default.aspx. Accessed June 5, 2014.

        • Levine J.A.
        • Schleusner S.J.
        • Jensen M.D.
        Energy expenditure of nonexercise 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 J.A.
        • Lanningham-Foster L.M.
        • McCrady S.K.
        • et al.
        Interindividual variation in posture allocation: possible role in human obesity.
        Science. 2005; 307: 584-586
        • Levine J.A.
        • Eberhardt N.L.
        • Jensen M.D.
        Role of nonexercise activity thermogenesis in resistance to fat gain in humans.
        Science. 1999; 283: 212-214
        • Teske J.A.
        • Billington C.J.
        • Kotz C.M.
        Neuropeptidergic mediators of spontaneous physical activity and non-exercise activity thermogenesis.
        Neuroendocrinology. 2008; 87: 71-90
        • Novak C.M.
        • Levine J.A.
        Central neural and endocrine mechanisms of non-exercise activity thermogenesis and their potential impact on obesity.
        J Neuroendocrinol. 2007; 19: 923-940
        • Hill J.O.
        • Peters J.C.
        Environmental contributions to the obesity epidemic.
        Science. 1998; 280: 1371-1374
        • Levine J.A.
        Poverty and obesity in the U.S.
        Diabetes. 2011; 60: 2667-2668
        • Ben-Ner A.
        • Hamann D.J.
        • Koepp G.
        • Manohar C.U.
        • Levine J.
        Treadmill workstations: the effects of walking while working on physical activity and work performance.
        PLoS One. 2014; 9: e88620
        • Ruff R.R.
        • Rosenblum R.
        • Fischer S.
        • Meghani H.
        • Adamic J.
        • Lee K.K.
        Associations between building design, point-of-decision stair prompts, and stair use in urban worksites.
        Prev Med. 2014; 60: 60-64
        • Maizlish N.
        • Woodcock J.
        • Co S.
        • Ostro B.
        • Fanai A.
        • Fairley D.
        Health cobenefits and transportation-related reductions in greenhouse gas emissions in the San Francisco Bay area.
        Am J Public Health. 2013; 103: 703-709

      Linked Article