高強度運動或可減緩肌肉衰老

The toll that aging takes on a body extends all the way down to the cellular level. But the damage accrued by cells in older muscles is especially severe, because they do not regenerate easily and they become weaker as their mitochondria, which produce energy, diminish in vigor and number.

衰老對身體造成的損害一直延伸到細胞層面。但在衰老的肌肉中，細胞累積的損傷尤為嚴重，因為它們不易再生。而當細胞內產生能量的線粒體活力和數量減少，這些細胞會更加衰弱。

A study published this month in Cell Metabolism, however, suggests that certain sorts of workouts may undo some of what the years can do to our mitochondria.

《細胞-代謝》(Cell Metabolism)雜志本月發(fā)表的一項研究卻表明，某些類型的鍛煉或許能消除歲月對我們的線粒體造成的影響。

Exercise is good for people, as everyone knows. But scientists have surprisingly little understanding of its cellular impacts and how those might vary by activity and the age of the exerciser.

眾所周知，鍛煉對人有益。但關于運動對細胞的影響，以及這些影響因活動和鍛煉者的年紀不同會如何變化，科學家的了解出奇地少。

So researchers at the Mayo Clinic in Rochester, Minn., recently conducted an experiment on the cells of 72 healthy but sedentary men and women who were 30 or younger or older than 64. After baseline measures were established for their aerobic fitness, their blood-sugar levels and the gene activity and mitochondrial health in their muscle cells, the volunteers were randomly assigned to a particular exercise regimen.

因此，明尼蘇達州羅切斯特梅奧診所(Mayo Clinic)的研究人員近期對72名30歲及以下或64歲以上、身體健康但習慣久坐不動的男性和女性進行了實驗。在確立志愿者的有氧體能、血糖指數以及肌肉細胞中基因活性和線粒體健康的基準后，他們會被隨機分配到一個特定的鍛煉方案。

Some of them did vigorous weight training several times a week; some did brief interval training three times a week on stationary bicycles (pedaling hard for four minutes, resting for three and then repeating that sequence three more times); some rode stationary bikes at a moderate pace for 30 minutes a few times a week and lifted weights lightly on other days. A fourth group, the control, did not exercise.

志愿者中的一部分人每周需進行多次高強度的舉重訓練;一部分每周需進行三次短時間的健身腳踏車間歇訓練(用力蹬車4分鐘，休息3分鐘，再如此重復3次);還有一部分人每周以適中的速度蹬車數次，每次30分鐘，并在其他時候做低強度舉重訓練。第四組為對照組，不做運動。

After 12 weeks, the lab tests were repeated. In general, everyone experienced improvements in fitness and an ability to regulate blood sugar.

實驗室測驗在12周以后再次重復?？偟膩碚f，每個人的健康狀況和血糖調節(jié)能力都有所改善。

There were some unsurprising differences: The gains in muscle mass and strength were greater for those who exercised only with weights, while interval training had the strongest influence on endurance.

有些差別是預料之中的：僅做了舉重訓練的志愿者在肌肉量和力量方面有更顯著的增加，而間歇訓練對耐力的作用最大。

But more unexpected results were found in the biopsied muscle cells. Among the younger subjects who went through interval training, the activity levels had changed in 274 genes, compared with 170 genes for those who exercised more moderately and 74 for the weight lifters. Among the older cohort, almost 400 genes were working differently now, compared with 33 for the weight lifters and only 19 for the moderate exercisers.

但在肌肉細胞活檢中出現(xiàn)了更多出人意料的結果。在較年輕的試驗對象中，進行了間歇訓練的志愿者有274個基因出現(xiàn)了活性水平變化，相比之下，運動適中的志愿者出現(xiàn)變化的基因有170個，做舉重運動的有74個。在年紀較大的組別內，有將近400個基因現(xiàn)已有活性的改變，相比之下，舉重運動者有33個，運動適中者僅有19個。

Many of these affected genes, especially in the cells of the interval trainers, are believed to influence the ability of mitochondria to produce energy for muscle cells; the subjects who did the interval workouts showed increases in the number and health of their mitochondria — an impact that was particularly pronounced among the older cyclists.

大多數受到影響的基因——尤其是進行間歇訓練的志愿者細胞中的基因——都被認為影響了線粒體為肌肉細胞制造能量的能力;進行了間歇運動的實驗對象表現(xiàn)出了線粒體數量和健康狀況的提高——這個影響在年紀較大的腳踏車運動者中尤其顯著。

It seems as if the decline in the cellular health of muscles associated with aging was “corrected” with exercise, especially if it was intense, says Dr. Sreekumaran Nair, a professor of medicine and an endocrinologist at the Mayo Clinic and the study’s senior author. In fact, older people’s cells responded in some ways more robustly to intense exercise than the cells of the young did — suggesting, he says, that it is never too late to benefit from exercise.

該項研究的資深作者、梅奧診所醫(yī)學教授、內分泌學家斯利庫馬蘭·奈爾博士(Dr. Sreekumaran Nair)說，與衰老有關的肌肉細胞健康程度下降似乎可以通過運動來“修正”，尤其是高強度的運動。事實上，年長者的細胞對高強度運動的反應比年輕人的更加強烈——他表示，意思就是，從運動中受益是不存在“太晚”這一說的。