Relax - it's the safest way to sit  Times Online, UK -

The Times November 28, 2006

Slouch - it's the safest way to sit
David Rose

Relaxing eases pressure on spine

Back pain is part of human nature

Leading article: Backtrack: the medical benefits of slouching on the couch

Your mother probably told you, as her mother told her: sit up straight. Whether at table, in class or at work we have always been told that sitting stiff-backed and upright is good for our bones, our posture, our digestion, our alertness and our general air of looking as if we are plugged into the world.

Now research suggests that we would be far better off slouching and slumping. Today’s advice is to let go and recline. Using a new form of magnetic resonance imaging (MRI), a team of radiologists have found that sitting up straight puts unneccesary strain on the spine and could cause chronic back pain because of trapped nerves or slipped discs.

The ideal angle for office workers who sit for long periods is about 135 degrees. It might make working at a computer impractical but it will put less pressure on the spine than a hunched or upright position, the researchers say.

The study at Woodend Hospital in Aberdeen involved 22 healthy volunteers who had no history of back pain or surgery. They adjusted their posture while being scanned by a movable MRI machine, assuming three sitting positions: a slouch, with the body hunched forward over a desk or video game console; an upright 90-degree sitting position; and a relaxed position where the patient reclined at 135 degrees but kept their feet on the floor.

By measuring the spinal angles and the arrangement and height of spinal discs and movement across the positions, the radiologists found that the relaxed posture best preserved the spine’s natural shape.

Waseem Amir Bashir, from Edinburgh, lead author of the study, said: “When pressure is put on the spine it becomes squashed and misaligned. A 135-degree body-thigh sitting posture was demonstrated to be the best biomechanical sitting position, as opposed to a 90-degree posture, which most people consider normal.

“Sitting in a sound anatomic position is essential, since the strain put on the spine and its associated muscles and ligaments over time can lead to pain, deformity and chronic illness.” Dr Bashir, who now works at the University of Alberta Hospital in Canada, presented the research yesterday at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.

The study was the first of its kind because MRI scan- ning has previously required patients to lie flat.

Back pain is the cause of one in six days off work and about 80 per cent of Britons are expected to suffer from it at some point. Office workers and school children may stave off future back problems by correcting their sitting posture and finding a chair that allows them to recline, Dr Bashir said.

He added: “We were not created to sit down for long hours, but somehow modern life requires the vast majority of the global population to work in a seated position, The best position for our backs is arguably lying down, but this is hardly practical.”

However, Gordon Waddell, an orthopaedic surgeon at the Glasgow Nuffield Hospital, said that the link between biomechanics as shown in MRI scans and preventing back pain was still very theoretical.

It was “human nature” to develop back pain, he said. “Like a headache or a cold, it seems we all get back pain and most of the evidence suggests that sitting position does not make a difference.”

Sick leave

Non-specific back pain accounts for about 5 million lost working days per year, one in six of the reported total, costing the economy at least £5.7 billion

In 2004-05, 452,000 people reported suffering back pain caused by, or made worse by, work

About a sixth of the total were new cases

Back-pain sufferers took an average of 19 days off per person last year and 11 per cent of the 2.8 million claimants of incapacity benefit said they had a musculoskeletal disorder

40 per cent of adults have suffered from back pain lasting for more than a day in the previous 12 months
Source: Health and Safety Executive, ONS

 

最健康坐姿 身體後傾135度

蘋果日報 2006年11月29日 星期三

【劉怡女╱綜合外電報導】英國與加拿大科學家昨天發表一項推翻傳統理論的研究，指出「坐直」並非最健康的姿勢。身體後傾、與大腿約呈135度、並且雙腳觸地的放鬆坐姿，才最能減少脊椎所承受壓力。

挺直最傷脊椎
英國亞伯丁伍登醫院、以及加拿大亞伯達大學醫院的研究人員，將坐姿分為脊椎與大腿呈90度的「挺直」、低於90度的「前俯」、以及高於90度的「後仰」，並針對22名背部健康的實驗對象，透過新型可移動式核磁共振造影機，測量他們的脊椎角度及椎間盤活動。
測量結果發現，挺直坐姿造成最多脊椎壓力，前俯坐姿次之，壓力最輕的是後仰坐姿。
研究人員巴榭爾（Waseem Amir Bashir）解釋：「壓力會擠歪脊椎，久而久之造成肌肉與韌帶疼痛、變形、甚至慢性病。後傾135度是最符合生物力學的坐姿。」

胖老鼠們注意了

Nature (01 Nov 2006) Article

美研究：紅酒抗氧化物　讓肥老鼠仍能延年益壽
東森新聞報 更新日期: 2006/11/02 13:37 記者:記者管淑平／編譯

早有醫學研究指出紅酒的好處，1日一份美國研究報告更指出，紅酒中的一種抗氧化萃取物讓實驗老鼠即使吃下高油脂食物，吃的胖胖的仍然活得健康又長壽。
哈佛大學醫學院和美國國家老化研究中心共同進行的動物研究顯示，從紅酒中萃取高量的抗氧化物白藜蘆醇(Resveratrol)能夠降低糖尿病機率，肝臟問題或者其他與肥胖相關的疾病，而且也能讓肥胖老鼠壽命比沒接受這種物質的胖老鼠長，死亡率也降低31%。
研究負責人哈佛大學醫學院分子生物學博士辛克萊爾說，令人驚訝的是，白藜蘆醇讓原本應該受肥胖影響出現問題的老鼠器官意外地運作正常，他們還在進行中的實驗則顯示出，這種物質也可望延長一般體型老鼠的壽命。
多年來的醫學研究已經提出紅酒對健康的益處，但是哈佛的這份研究則首次發現能讓哺乳動物即使肥胖還保持健康的物質。辛克萊爾認為，關鍵可能在於抗老化基因 SIRT1，白藜蘆醇活化了這類基因的活動。他說，他們的研究有可能達到人類長期以來尋找的目標，活得長壽又健康，「10萬年來我們都在尋找這種物質，或許它就在眼前了，只要一顆藥丸就能延緩老化的疾病，讓你保持健康。」他形容這項成果的重要性就如「老化研究的聖杯。」
白藜蘆醇是植物對抗病蟲害時釋放出的多酚物質，存於葡萄這類漿果類的果皮或者花生中，有益於抗氧化，防心血管疾病和癌症。過去研究發現白藜蘆醇能延長果蠅和魚類的壽命，這次哈佛的研究在哺乳動物老鼠身上實驗是否同樣有效。
研究人員將一群一歲的實驗老鼠分成三組，1/3採標準飲食，1/3吃如速食店的高脂肪飲食，牠們的60%熱量來源是脂肪，另外1/3採同樣高脂肪飲食但是同時吸收高劑量白藜蘆醇，每1公斤體重餵24毫克。觀察一年後發現，高量的白藜蘆醇讓55隻胖老鼠即使肥胖，健康和活動力仍然如正常老鼠，死亡率也減少 31%，壽命平均延長10%到20%﹔另一組高脂肪飲食但沒接受白藜蘆醇的老鼠也變胖，並有肝臟肥大，和早期的糖尿病和心臟病。
1歲的老鼠相當於人類的中年年紀，老鼠壽命延長15%，相當於人類壽命延長約10年。辛克萊爾說，「這的確很讓人驚訝，這些老鼠還是很胖，但是他們就像瘦老鼠一樣健康」，活動能力測驗的表現與年輕瘦老鼠一樣好﹔實驗老鼠有關健康的幾項重要指數唯一未見改善的就是膽固醇值，不過辛克萊爾認為，這並不影響實驗老鼠的整體健康。
不過研究人員提醒，同樣的效果是否也會出現在人類身上目前還言之過早，杜克大學飲食與健康研究中心主任艾森松也要大家別高興的太早，因為科學研究最忌諱從實驗室研究，特別是動物實驗成果就妄下斷論認為也對人體有用。此外，要達到實驗中採用的高劑量白藜蘆醇，必須喝下一天上千杯的紅酒，對人體是否安全仍有待證實，國家老化研究中心主任赫德斯呼籲民眾，不要自行亂服用白藜蘆醇補充品。
這份研究報告1日在「自然」期刊發表，辛克萊爾正就白藜蘆醇對肥胖者的保健效果進行初步人體實驗，此外，也考慮對物種演化上與人類相近的恆河猴做實驗。
哈佛研究紅酒抗氧化物白藜蘆醇的延年益壽效果。圖為15個月大的實驗老鼠，上圖左到右分採A：標準飲食，B：高脂肪飲食，C：高脂肪飲食加白藜蘆醇。下圖左到右為B，A，C。（圖／美聯社）