多運動也許真的可以令你老得慢大綱
Almost any amount and type of physical activity may slow aging deep within our cells, a new study finds. And middle age may be a critical time to get the process rolling, at least by one common measure of cell aging.
一項新研究發現，不論運動量如何，幾乎所有種類的體育活動都能延緩深藏於我們細胞內部的衰老過程。而中年可能是讓這一機制繼續運行下去的關鍵時段，至少，就衡量細胞衰老的一個常用指標而言確是如此。
Dating a cell’s age is tricky, because its biological and chronological ages rarely match. A cell could be relatively young in terms of how long it has existed but function slowly or erratically, as if elderly.
確定細胞的年齡可是個棘手差事，因爲它們的生物學年齡（表明其組織結構和生理功能的狀態）和實際年齡基本上對不上號。有些細胞論其存在時間可能還算年輕，但它們執行起生理機能來卻十分緩慢或者不穩定，就如同衰老的細胞一樣。
Today, many scientists have begun determining a cell’s biological age — meaning how well it functions and not how old it literally is — by measuring the length of its telomeres.
如今，許多科學家開始通過測量細胞的端粒長度來確定它的生物學年齡。
For those of us who don’t know every portion of our cells’ interiors, telomeres are tiny caps found on the end of DNA strands, like plastic aglets on shoelaces. They are believed to protect the DNA from damage during cell division and replication.
我們中的一些人對細胞內部的各個結構並不都那麼瞭如指掌，那麼，打個比方來解釋一下，端粒是DNA鏈末端的小帽子，就像鞋帶上的塑料箍一樣。科學家們認爲，它們可以防止DNA在細胞分裂和DNA複製過程中受到損傷。
As a cell ages, its telomeres naturally shorten and fray. But the process can be accelerated by obesity, smoking, insomnia, diabetes and other aspects of health and lifestyle.
隨着細胞的衰老，其端粒自然也會磨損和縮短。但這一過程可能會因肥胖、吸菸、失眠、糖尿病等健康和生活方式問題而加快。
In those cases, the affected cells age prematurely.
在這種情況下，受影響的細胞就會過早衰老。
However, recent science suggests that exercise may slow the fraying of telomeres. Past studies have found, for instance, that master athletes typically have longer telomeres than sedentary people of the same age, as do older women who frequently walk or engage in other fairly moderate exercise.
然而，最近的科學研究表明，鍛鍊身體可以減緩端粒的磨損。例如，既往的研究發現，運動健將們的端粒通常比同齡的久坐者更長，在經常步行或從事其他適度運動的老年婦女中也有同樣的現象。
But those studies were relatively narrow, focusing mostly on elderly people who ran or walked. It remained unclear whether people of different ages who engaged in a variety of exercises would likewise show effects on their telomeres.
但是，這些研究的面相對較窄，主要集中在經常跑步或步行的老年人身上。目前尚不清楚在不同年齡段的人羣當中，從事多種運動是否也會對他們的端粒造成影響。
So for the new study, which was published this month in Medicine & Science in Sports & Exercise, researchers from the University of Mississippi and University of California, San Francisco, decided to look more broadly at the interactions of exercise and telomeres among a wide swath of Americans.
於是，在這項10月發表在《運動與鍛鍊中的醫學與科學》雜誌(Medicine & Science in Sports & Exercise)上的新研究中，來自密西西比大學(University of Mississippi)和加州大學舊金山分校(University of California, San Francisco)的研究人員們決定在廣大的美國人羣中更廣泛地探討一下運動與端粒之間的相互作用。
To do so, they turned to the immense trove of data generated by the ongoing National Health and Nutrition Examination Survey, for which tens of thousands of adults answer questions annually about their health, including their exercise habits, and complete an in-person health exam, providing a blood sample.
爲此，他們把目光轉向了正在進行的美國健康與營養調查(National Health and Nutrition Examination Survey)所產生的巨大的數據寶庫。在這項調查中，成千上萬的成年人每年都會回答有關他們自己的健康狀況（包括運動習慣）的問題，接受體檢，並提供血液樣本。
In recent years, those blood samples have been tested for, among other markers of health, telomere length in the participants’ white blood cells.
近年來，研究人員對這些血樣進行了化驗，檢測了參與者白細胞的端粒長度等多種健康標誌物。
The researchers gathered the data for about 6,500 of the participants, ranging in age from 20 to 84, and then categorized them into four groups, based on how they had responded to questions about exercise.
研究人員收集了約6500名年齡在20歲到84歲的參與者的數據，然後根據他們對運動相關問題的回答，把他們分爲四組。
Those questions in this survey tended to be broad, asking people only if, at any time during the past month, they had engaged in weight training, moderate exercise like walking, more vigorous exercise like running, or have walked or ridden a bike to work or school.
這項調查只是籠統地詢問了受訪者在過去的一個月裏是否曾進行過任何負荷訓練、或步行等中等強度的運動、或跑步等較爲劇烈的運動，又或者曾步行或騎自行車上班或上學。
If a participant answered yes to any of those four questions, he or she earned a point from the researchers. So, someone who reported walking received a point. If he also ran, he earned another, and so on, for a maximum of four points.
在上述四個問題中，參與者的每一個肯定回答都會被研究人員計一分。因此，報告曾經步行過的人可以得一分。如果他還跑步了，就能再得一分，依此類推，最多可以得四分。
The researchers then compared those tallies to each person’s telomere length.
然後，研究人員比較了這些人的端粒長度及其得分。
And there were clear associations. For every point someone gained from any type of exercise, his or her risks of having unusually short telomeres declined significantly.
結果發現其間存在明顯的相關性。無論受訪者從事了何種類型的運動，他每得一分，端粒長度異常縮短的風險都會顯著下降。
Specifically, someone who participated in a single activity, earning them a 1, was about 3 percent less likely to have very short telomeres than someone who didn’t exercise at all.
具體而言，如果某人因爲參加某一運動而贏得1分，他的端粒特別短的可能性就會比不鍛鍊的人低3%左右。
That risk declined more substantially if someone exercised more. People who reported two types of exercise were 24 percent less likely to have short telomeres; three types of exercise were 29 percent less likely; and those who had participated in all four types of activities were 59 percent less likely to have very short telomeres.
一個人鍛鍊得越多，這種風險下降的幅度就越大。報告從事兩種運動的人端粒特別短的可能性要降低24%；從事三種運動的人風險降低29%；參與了所有四種運動的人風險降低59%。
Interestingly, these associations were strongest among people between the ages of 40 and 65, the researchers found, suggesting that middle age may be a key time to begin or maintain an exercise program if you wish to keep telomeres from shrinking, says Paul Loprinzi, an assistant professor of health and exercise science at the University of Mississippi. He was a co-author of the study with Jeremy Loenneke, also of the University of Mississippi, and Elizabeth Blackburn, a professor at the University of California, San Francisco, who shared a Nobel Prize in 2009 for the discovery of the molecular nature of telomeres.
有趣的是，研究人員發現，這種相關性在40歲至65歲人羣中最強。密西西比大學的健康與運動科學助理教授保羅·羅普林茨(Paul Loprinzi)認爲，這表明，要是你不想讓端粒縮短，中年可能是開始或者堅持鍛鍊計劃的關鍵時段。他與密西西比大學的傑里米·倫內克(Jeremy Loenneke)、加州大學舊金山分校(University of California, San Francisco)的伊麗莎白·布萊克本(Elizabeth Blackburn)教授同爲本研究的共同作者，而布萊克本教授曾因發現了端粒的分子性質而與其他人分享了2009年的諾貝爾獎。
However, as Dr. Loprinzi points out, this study is purely associational, so cannot show whether exercise actually causes changes in telomere length, only that people who exercise have longer telomeres.
然而，正如羅普林茨博士指出的那樣，這項研究只是個純粹的相關性研究，所以它只表示鍛鍊的人端粒較長，卻無法說明運動是否確實會導致端粒長度的變化。
The study also couldn’t tease out the ideal amount of exercise for telomere maintenance, Dr. Loprinzi say, because the survey asked only whether someone exercised at all, not how frequently.
羅普林茨博士還說，由於調查只詢問了受訪者是否進行過鍛鍊，並沒有問及鍛鍊的頻率，所以這項研究無法確定要維持端粒長度所需的理想運動量。
Perhaps most important, the results don’t tell us whether longer telomeres translate into better health. But, Dr. Loprinzi says, other studies, including from his lab, “have shown that telomeres are predictive of mortality,” with shorter telomeres equating to shorter lives.
也許最重要的是，研究結果並沒能告訴我們，端粒較長是否就代表着更加健康。但是，羅普林茨博士表示，包括他自己實驗室的在內的其他研究“顯示，端粒對死亡有預測意義”，較短的端粒就等同於較短的壽命。
So the message seems clear, he says. “Exercise is good” for your cells, and “more exercise in greater variety” is likely to be even better.
因此，箇中啓示很明確，他說，“運動對你的細胞有益”，且“越多地進行多種鍛鍊”效果可能就越好。
