少坐多運動 一定會更長壽嗎大綱

If people need motivation to get up from their office chairs or couches and become less sedentary, two useful new studies could provide the impetus. One found that sitting less can slow the aging process within cells, and the other helpfully underscores that standing up — even if you are standing still — can be good for you as well.

如果人們需要一些動力才願意從辦公椅和沙發上站起來，少坐一會兒，那麼兩項有用的新研究能提供這種動力。其中一項研究發現，少坐能減緩細胞衰老速度；另一項研究強調站立——哪怕只是靜靜地站着——也對健康有益。

For most of us nowadays, sitting is our most common waking activity, with many of us sitting for eight hours or more every day. Even people who exercise for an hour or so tend to spend most of the remaining hours of the day in a chair.

靜坐是我們大部分人清醒時最常見的狀態，很多人每天坐八小時以上。甚至連那些每天鍛鍊一小時左右的人其他大部分時間也都是坐着。

The health consequences of this sedentariness are well-documented. Past studies have found that the more hours that people spend sitting, the more likely they are to develop diabetes, heart disease and other conditions, and potentially to die prematurely — even if they exercise regularly.

久坐會帶來健康隱患，這一點證據確鑿。過去的研究發現，人們坐的時間越長，越有可能患上糖尿病和心臟病等疾病，甚至可能早死——即使進行有規律地鍛鍊。

But most of these studies were associational, meaning that they found a link between sitting and illness, but could not prove whether or how sitting actually causes ill health.

但是這些研究大多得出的是關聯性結論，也就是說，它們發現久坐與患病有關，但是不能證明久坐是否的確或者如何導致健康問題。

So for the most groundbreaking of the new studies, which was published this month in the British Journal of Sports Medicine, scientists in Sweden decided to mount an actual experiment, in which they would alter the amount of time that people spent exercising and sitting, and track certain physiological results. In particular, with this experiment, the scientists were interested in whether changes in sedentary time would affect people’s telomeres.

到目前爲止，新研究中最具突破性的是本月在《英國運動醫學雜誌》(British Journal of Sports Medicine)上發表的研究——瑞典科學家們決定進行一項實際實驗，他們在實驗中改變人們鍛鍊和靜坐的時間長度，然後追蹤某些生理後果。科學家們對這個實驗最感興趣的是，這些改變是否會影響人們的染色體端粒。

If you are unfamiliar with the componentry of your genes, telomeres are the tiny caps on the ends of DNA strands. They shorten and fray as a cell ages, although the process is not strictly chronological. Obesity, illness and other conditions can accelerate the shortening, causing cells to age prematurely, while some evidence suggests that healthy lifestyles may preserve telomere length, delaying cell aging.

你可能對基因的組成部分不太瞭解，所以我簡單介紹一下，染色體端粒是DNA鏈條末端的小帽子。隨着細胞老化，它們會縮短、磨損，不過這一過程不完全由時間決定。肥胖、疾病和其他健康問題會加速端粒縮短，導致細胞提前老化，而有些證據表明健康的生活方式能維持端粒長度，延緩細胞衰老。

For the new experiment, the Swedish scientists recruited a group of sedentary, overweight men and women, all aged 68, and drew blood, in order to measure the length of telomeres in the volunteers’ white blood cells. Then half of the volunteers began an individualized, moderate exercise program, designed to improve their general health. They also were advised to sit less.

爲了這個新實驗，瑞典科學家招募了一羣習慣久坐的68歲超重男女，採血測量他們白細胞中端粒的長度。然後，其中一半志願者開始個性化的適度鍛鍊計劃，旨在提高總體健康狀況。同時建議他們少坐。

The other volunteers were told to continue with their normal lives, although the scientists urged them to try to lose weight and be healthy, without offering any specific methods.

科學家們讓其他志願者繼續像往常那樣生活，但是鼓勵他們儘量減肥，保持健康，不過沒有提供具體方法。

After six months, the volunteers all returned for a second blood draw and to complete questionnaires about their daily activities. These showed that those in the exercise group were, not surprisingly, exercising more than they had been previously. But they were also, for the most part, sitting substantially less than before.

六個月後，志願者們第二次抽血，完成關於日常活動的問卷。結果表明，鍛鍊組的人不出所料比從前鍛鍊得更多。但是他們大部分人坐的時間也比從前少了很多。

And when the scientists compared telomeres, they found that the telomeres in the volunteers who were sitting the least had lengthened. Their cells seemed to be growing physiologically younger.

科學家們在比較端粒時發現，坐得最少的志願者的端粒延長了。從生理上講，他們的細胞似乎更年輕了。

Meanwhile, in the control group telomeres generally were shorter than they had been six months before.

與此同時，控制組志願者的端粒總體來說比六個月前更短了。

But perhaps most interesting, there was little correlation between exercise and telomere length. In fact, the volunteers in the exercise group who had worked out the most during the past six months tended now to have slightly less lengthening and even some shortening, compared to those who had exercised less but stood up more.

但是也許最有趣的是，鍛鍊與端粒長度之間幾乎沒有聯繫。實際上，在鍛鍊組中，在這六個月裏鍛鍊最多的人與鍛鍊得不多但是站立時間更長的人相比，端粒增長得略微少一些，有些甚至縮短了。

Reducing sedentary time had lengthened telomeres, the scientists concluded, while exercising had played little role.

科學家們得出結論，減少靜坐時間延長了端粒長度，而鍛鍊對此幾乎毫無作用。

Exactly what the volunteers did in lieu of sitting is impossible to say with precision, said Per Sjögren, a professor of public health at Uppsala University in Sweden, who led the study, because the researchers did not track their volunteers’ movement patterns with monitors. But “it’s most likely,” he said, that “sitting time was predominantly replaced with low-intensity activities,” and in particular with time spent standing up.

這項研究的領導者、瑞典烏普薩拉大學的公共健康教授佩爾·肖格倫(Per Sjögren)說，志願者們用什麼活動來代替靜坐無從準確得知，因爲研究者們沒用監測器追蹤志願者們的活動模式。但是他說，“最可能的情況是，靜坐時間主要是被低強度的活動代替”，尤其是站立。

Which makes the second new study of sedentary behavior particularly relevant. Standing is not, after all, physically demanding for most people, and some scientists have questioned whether merely standing up — without also moving about and walking — is sufficiently healthy or if standing merely replaces one type of sedentariness with another.

這讓另一項關於靜坐行爲的新研究顯得格外重要。畢竟，對大多數人來說，站立不是生理需求。有些科學家質疑，只是站立——不動，也不行走——是否足夠健康；站立是否只是另一種形式的久坐。

If so, standing could be expected to increase health problems and premature death, as sitting has been shown to do.

如果是這樣的話，站立可能會和靜坐一樣增加健康問題，導致早逝。

To find out whether that situation held true, Peter Katzmarzyk, a professor of public health at the Pennington Biomedical Research Center in Baton Rouge, La., and an expert on sedentary behavior, turned to a large database of self-reported information about physical activity among Canadian adults. He noted the amount of time that the men and women had reported standing on most days over the course of a decade or more and crosschecked that data with death records, to see whether people who stood more died younger.

爲了弄清那種情況是否屬實，路易斯安那州巴吞魯日彭寧頓生物醫學研究中心的公共健康教授、靜坐行爲研究專家彼得·卡茲馬茲克(Peter Katzmarzyk)開始研究一個巨大的數據庫，裏面是加拿大成年人自我陳述的身體活動信息。他記下那些人在十年或更長時間內大部分日子裏站立的時間，與死亡檔案裏的數據交叉檢查，看看那些站得更多的人是否死得更早。

The results, published in May in Medicine & Science in Sports & Exercise, are soothing if predictable. Dr. Katzmarzyk found no link between standing and premature death. Rather, as he writes in the study, “mortality rates declined at higher levels of standing,” suggesting that standing is not sedentary or hazardous, a conclusion with which our telomeres would likely concur.

今年5月，他的研究結果在《運動鍛鍊醫學科學》(Medicine & Science in Sports & Exercise)上發表。結果不出意料，令人安慰。卡茲馬茲克發現站立和早逝之間沒有關係。相反，他在研究報告中寫道，“站立時間越長，死亡率越低”，稱站立不同於久坐，沒有危害——我們的端粒很可能會贊同這一結論。