Sitting

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"Sit" redirects here. For other uses, see Sit (disambiguation).
Sitzender Junge ("Sitting boy") by Werner Stötzer, 1956

Sitting is a rest position supported by the buttocks or thighs where the torso is more or less upright. Large-scale studies show that people who regularly sit for hours at a time have higher mortality rates due to heart disease, diabetes and cancer.

Role and evolution of sitting[edit]

Women reclining in chairs. Painting by Jean-François de Troy.

According to the British Chiropractic Association, 32% of the British population spends more than ten hours per day sitting down.[1] However, chairs with backrests have only been common in Europe since the 16th century and office workers sitting at work was uncommon even in the early 20th century.[2]

Sitting positions[edit]

Sitting on the floor[edit]

The most common ways of sitting on the floor involve bending the knees. One can also sit with the legs unbent, using something solid as support for the back or leaning on one's arms. Sitting with bent legs can be done with the legs mostly parallel or by crossing them over each other.

A common cross-legged position is with the lower part of both legs folded towards the body, crossing each other at the ankle or calf, with both ankles on the floor, sometimes with the feet tucked under the knees or thighs. The position is known in several European languages as tailor style, from the traditional working posture of tailors;[3] compare tailor's bunion. It is also named after various plains-dwelling nomads: in English Indian style, in many European languages "Turkish style", and in Japanese agura (胡座 The sitting style of non-Han ethnics (particularly Turks, Mongols and other Central Asians.)?). In yoga it is known as sukhasana.

Sitting on a raised seat[edit]

Girl sitting on a chair.

Most raised surfaces at the appropriate height can be used as seats for humans, whether they are made for the purpose, such as chairs, stools and benches, or not. While the buttocks are nearly always rested on the raised surface, there are many differences in how one can hold one's legs and back.

There are two major styles of sitting on a raised surface. The first has one or two of the legs in front of the sitting person; in the second, sitting astride something, the legs incline outwards on either side of the body.

The feet can rest on the floor, or on a footrest, which can keep them vertical, horizontal, or at an angle in between. They can also dangle if the seat is sufficiently high. Legs can be kept right to the front of the body, spread apart, or one crossed over the other.

The upper body can be held upright, recline to either side or backwards, or one can lean forward.

Yoga, traditions, and spirituality[edit]

The Japanese tea ceremony is performed sitting in seiza.

There are many, many seated positions in various traditions and rituals. Four examples are:

  • Seiza (正座?) "correct sitting" is a Japanese word which describes the traditional formal way of sitting in Japan. Sitting in seiza is kneeling on one's own lower legs, with the feet under the buttocks, toes pointed backwards. To sit in seiza for any length of time requires careful positioning of the heels under the sit bones of the hip, to minimize circulation loss. A related position is kiza (跪座?), which differs in the tops of the feet being raised off the ground.
  • Vajrasana (Diamond Pose) is a yoga posture (asana) similar to seiza.
  • The lotus position involves resting each foot on the opposite thigh so that the soles face upwards. If only one foot is brought into this position, it is called a half-lotus position. This position is common in yoga and meditation.
  • The Burmese position, named so because of its use in Buddhist sculptures in Burma, places both feet in front of the pelvis with knees bent and touching the floor to the sides. The heels are pointing toward pelvis or upward, and toes are pointed so that the tops of the feet lie on the ground. This looks similar to the cross legged position, but the feet are not placed underneath the thigh of the next leg, therefore the legs do not cross. Instead, one foot is placed in front of the other. This is a popular sitting alternative for those less comfortable with the use of the Lotus or half Lotus positions in meditation and yoga.

In various mythologies and folk magic, sitting is a magical act that connects the person who sits, with other persons, states or places where he/she sat.[4]

Health risks[edit]

Heart disease, diabetes and cancer[edit]

Since 2010, (based on research beginning as early as the mid-90s) dozens of studies have been published showing greatly increased mortality among those who regularly spend prolonged periods sitting, including among those who exercise regularly.

Large-scale studies[edit]

A paper[5] examining 123,000 people over a 14-year period, published in 2010 by the American Cancer Society, showed that "Women who sit for more than six hours daily are around 40 per cent more likely to die than those sitting for less than three hours a day".

A paper[6] published in 2012, studying 240,000 adults in the USA over 8.5 years similarly found increased risks of "all-cause mortality" among those who spent a lot of time sitting, including those who exercised regularly.

Research published[7] in 2013, lead by Emma George at the University of Western Sydney, studying 60,000 middle-age men found "those who sit more than four hours a day" were at risk, and this was "independent of other health factors such as age, body-mass index and level of physical activity".

A study of 62,000 post-menopausal women over a 12-year period found that, after controlling for age, race, body mass index, physical activity, physical function, and chronic disease, there was a 12% higher death rate among those who spent eleven or more waking hours per day in a sitting or lying position compared to those who spent fewer than four hours sitting or lying.[8] A large part of this increased death rate was due to death by heart disease and by cancer being 27% and 21% higher, respectively.

Research and meta-analysis[edit]

In 2013, researchers at Leicester University reported that "time spent sitting is strongly associated with an increased risk of developing type 2 diabetes".[9]

Meta-research by the Toronto Rehabilitation Institute, looking at the data used in 41[10] scientific articles, published[11] in Annals of Internal Medicine in 2015 have shown significantly higher mortality rates among people who regularly sit for prolonged periods, and that these risks are not negated by regular exercise. The causes include heart disease, diabetes and cancer.

It has been shown that prolonged sitting has been linked to high blood pressure and raised cholesterol, and people with the most inactive time are more than twice as likely to have cardiovascular disease than others with the least.[12]

Inflammatory and metabolic risk factors partly explain this relationship.[13]

Some physical effects that seated people (for computer use or other activities) can experience are restricted blood flow to their muscles, such as neck, shoulders, upper limbs, and lower back.[14]

Reducing the health damage[edit]

Research is currently focussed on whether getting up one or more times per hour to walk or exercise can counteract the damage of prolonged sitting.[15] Research is still at an early stage[16] and, because of the inconvenience for test subjects, neither large-scale nor long duration studies have been attempted. However, short-term and small-group studies have shown that indeed, short bouts of light exercise prevent certain indicators which are seen during prolonged sitting (such as insulin spikes or hardening of arteries) and which are associated with heart disease, diabetes and cancer.

One Australian study[17] looking at insulin and glucose levels in the blood of 19 obese adults showed that, during a 5-hour period of sitting down, by getting up and performing light or moderate exercise every 20 minutes, it was possible to avoid the insulin and glucose spikes seen in the control group which sat without exercising.[18] The results were not influenced by the intensity of effort, light (walking) or moderate (jogging).

A similar study published[19] in 2014 by the UK's University of Bedfordshire looked at blood glucose levels and returned similar findings in a test group of ten non-obese men regarding exercise-breaks but also noted that a group who simply stood up during the breaks from sitting did not experience any of the benefits of those who did light exercise.

A study of femeral artery wall hardening, involving twelve non-obese men, found that three hours of sitting caused reduced flow-mediated dilation (widening of the artery in response to blood flow). But this reduction did not happen when the subjects performed the same test but got up and walked for five minutes three times during the three hours.[20]

Other suggestions from various bloggers and experts include sitting on an exercise ball instead of a chair, shifting about in your chair, fidgeting, or occasionally tensing the muscles in your body while sitting. However, there are no studies to suggest if these have any effect.

Posture[edit]

Back of a sitting nude by school of Rembrandt.

Sitting upright for hours causes increased stress on the back, and may be a cause of chronic back pain.[citation needed]

A 2006 study compared three sitting positions and found that the reclined position (135°) put less strain on the participants' backs compared to a straight position (90°) or a slouched forward position (less than 70°).[21] The study suggests a reclined seated position is best for office workers.

Optimal posture while sitting is now referred to as neutral spine.[22]

Some physical effects that seated people (for computer use or other activities) can experience are restricted blood flow to their muscles, such as neck, shoulders, upper limbs, and lower back.[23]

Muscle wasting is also a risk with prolonged sitting. Without regular use the hip flexors, the muscles become shorter and tighter. Decreased hip mobility is one of the main reasons elderly people fall.[12]

Kneeling chairs[edit]

The Kneeling chair (often just referred to as "ergonomic chairs"), was designed to encourage better posture than the conventional chair. To sit in a kneeling chair one rests one's buttocks on the upper sloping pad and rests the front of the lower legs atop the lower pad, i.e., the human position as both sitting and kneeling at the same time.

See also[edit]

References[edit]

  1. ^ "Sitting straight 'bad for backs'". Data from the British Chiropractic Association says 32% of the population spends more than 10 hours a day seated. Half do not leave their desks, even to have lunch. Two thirds of people also sit down at home when they get home from work. 
  2. ^ "Sitting down can send you to an early grave: Why sofas (and your office chair) should carry a health warning...". dailymail.co.uk. Chairs with backs only became available to the affluent in Europe around the 13th century, and it was not until the 16th century that they became common. Until then, the chest, bench or stool were the everyday seats. Sitting at work is a recent fad, as well. In the 19th and early 20th centuries, office workers such as clerks, accountants and managers mostly stood. Sitting was equated with slacking. 
  3. ^ "The Art of the Cut". History.org. Retrieved 2012-03-16. 
  4. ^ Čajkanović, Veselin; Živković, Marko (translator) (1996). "Magical Sitting". Anthropology of East Europe Review 14 (1). Retrieved 2007-07-09. It is obvious from all the above that sitting, seen from the viewpoint of the history of religion, could be a magical act which, within the framework of analogic magic, will establish a certain relationship, a covenant. 
  5. ^
  6. ^ "Amount of time spent in sedentary behaviors and cause-specific mortality in US adults.". National Cancer Institute. Overall sitting was associated with all-cause mortality. Even among adults reporting high levels of MVPA [moderate-vigorous physical activity] 
  7. ^ Report published in the International Journal of Behavioural Nutrition and Physical Activity, as quoted by UK Daily Mail: "Sitting down can send you to an early grave: Why sofas (and your office chair) should carry a health warning...". dailymail.co.uk. (...) sit more than four hours a day are more likely to experience chronic ailments, such as cancer, heart disease and high blood pressure (...) independent of other health factors such as age, body-mass index and level of physical activity 
  8. ^
    • "(abstract) Sedentary Behaviour and Mortality in Older Women". American Journal of Preventive Medicine. There was a linear relationship between greater amounts of sedentary time and mortality risk after controlling for multiple potential confounders. 
    • "Women who spend too long sitting may die earlier". UK National Health Service (article by Bazian). Overall there was a general trend for increasing sedentary time to be associated with increasing all-cause mortality, and mortality from cardiovascular disease (such as stroke and heart disease), heart disease specifically, and cancer. 
  9. ^ "Sitting down can send you to an early grave: Why sofas (and your office chair) should carry a health warning...". dailymail.co.uk. spending hours sitting down causes the body to accumulate dangerously high levels of sugars and fats in your bloodstream — significantly raising the risk of type 2 diabetes 
  10. ^ The study abstract states "Forty-seven articles", but then breaks them into three groups 14+14+13, which is only 41. The LA Times article uses the number 47, the CBC article uses 41.
  11. ^
  12. ^ a b Berjowitz, Bonnie; Patterson Clark (January 20, 2014). "The health hazards of sitting". The Washington Post. Retrieved 26 February 2014. 
  13. ^ Emmanuel Stamatakis, PhD, MSc, BSc*,*, Mark Hamer, PhD, MSc, BSc* and David W. Dunstan, PhD, BAppSc, Screen-Based Entertainment Time, All-Cause Mortality, and Cardiovascular Events J Am Coll Cardiol, 2011; 57:292-299
  14. ^ Subratty, Ah; Korumtollee (2005). "Occupational overuse syndrome among keyboard users in Mauritius". Indian Journal of Occupationa and Environmental Medicine 9 (2): 71. 
  15. ^
    • First source: "Regular walking breaks 'protect arteries'". Bazian. Researchers are particularly interested in whether taking breaks from unavoidable periods of sitting could potentially reduce any adverse effects ... 
    • Second source: See list of studies which follow in this section
  16. ^ "Regular walking breaks 'protect arteries'". Bazian. ...this research is still at an early stage. In the interim, it is safe to say that having short breaks from periods of inactivity isn’t harmful, and could turn out to be beneficial. 
  17. ^ In the abstract, Figure.1 clarifies that "obese" means BMI > 25; Figure.2 clarifies that all subjects sat for 2 hours uninterrupted, and then a further 5 hours of either uninterrupted sitting or 5 hours of sitting with 2 mins of exercise every 20 mins.
  18. ^ "Breaking up prolonged sitting reduces postprandial glucose and insulin responses.". Baker IDI Heart and Diabetes Institute. The glucose ... after both activity-break conditions was reduced ... compared with uninterrupted sitting. Insulin ... was also reduced with both activity-break conditions ... compared with uninterrupted sitting. 
  19. ^ "Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not.". Sports Medicine Australia. Glucose area under the curve was lower in the activity-break condition compared to the uninterrupted sitting and standing-break conditions 
  20. ^
    • "Effect of Prolonged Sitting and Breaks in Sitting Time on Endothelial Function.". Medicine & Science in Sports & Exercise. Conclusion: Three hours of sitting resulted in a significant impairment in shear rate and SFA FMD. When light activity breaks were introduced hourly during sitting, the decline in FMD was prevented. 
    • "Regular walking breaks 'protect arteries'". Bazian. The researchers found that the widening of the artery in response to blood flow (called flow-mediated dilation) reduced over three hours spent sitting without moving. However, getting up for five-minute walks in this period stopped this from happening. 
    • Note: The study's abstract's "Results" section says there was a difference in "shear rate" - decline in inactive group, no decline in active group - but the "Conclusion" section doesn't mention the shear rate of the active group, and the Bazian article says the researchers did not find any difference in shear rate. Unless someone can explain this, I suggest just not drawing any conclusions about shear rate in the Wikipedia article.
  21. ^ "Sitting straight 'bad for backs'". BBC News. 2006-11-28. Retrieved 2010-04-07. 
  22. ^ http://www.spineuniverse.com/displayarticle.php/article183.html
  23. ^ Subratty, Ah; Korumtollee (2005). "Occupational overuse syndrome among keyboard users in Mauritius". Indian Journal of Occupationa and Environmental Medicine 9 (2): 71. 

External links[edit]