新的研究表明 肌肉衰减并非不可避免

NEW RESEARCH SHOWS: MUSCLE LOSS IS NOT INEVITABLE

　

“70多岁和80多岁的运动员的大腿肌肉量几乎和40多岁的运动员一样多”

 

随着年龄的增长，身体虚弱是不可避免的吗? 这个问题困扰着科学家和中年人，尤其是当他们到达同样的年龄的时候。

 

直到最近，证据都令人沮丧。过去几年的大量研究表明，在40岁以后，人们通常每十年会失去8%或更多的肌肉量，这一过程在70岁之后显著加速。更少的肌肉量通常意味着更少的力量，活动能力的下降和老年人独立生活能力的下降。它也与过早死亡有关。

 

但是，越来越多的新兴科学表明，这种肌肉衰减并非不可阻挡。通过锻炼，这种观点认为，你也许可以为你的肌肉重写未来。看看上个月发表在《内科医生和运动医学》杂志上的一项激动人心的研究结果吧。为此，匹兹堡大学的研究人员招募了40名竞技运动员、自行车手和游泳运动员。他们年龄从40岁到81岁不等，每一组有5名男性和5名女性，分别代表4个年龄组:40岁至49岁、50岁至59岁、60岁至69岁、70岁以上。所有人都很健康，每周训练四到五次，经常参加比赛。一些人在最近的比赛中赢得了他们的年龄组比赛。

　

　

　

 

他们完成了详细的调查问卷，详细记录了他们的健康状况和每周的体育活动。然后，研究人员测量了他们的肌肉质量、腿部力量和身体组成，确定了他们身体，更确切地说，他们的肌肉组织中的脂肪占比。其他研究发现，随着人们年龄的增长，他们不仅会失去肌肉，还会使残留的组织变成脂肪，降低其质量并降低其强度。

 

然而，几乎没有证据表明老运动员的肌肉状况恶化。70多岁和80多岁的运动员的大腿肌肉量几乎和40多岁的运动员一样多，如果有任何脂肪的渗透，他们的大腿肌肉就会很小。运动员们也保持着强壮。正如科学家所指出的，在男性和女性中，60岁左右的腿部肌肉强度下降。他们不像50岁的人那样强壮，但差别不大，随之而来的是额外的下降。70岁和80岁的运动员和60岁的运动员一样强壮。

　

　

　

 

“我们认为这些都是非常令人鼓舞的结果，”整形外科医生、匹兹堡大学医学中心(University of Pittsburgh Medical Center)的硕士运动员研究项目的创始人Vonda Wright博士说。他们强烈建议人们在变老的过程中不必失去肌肉和功能。我们假设的变化是由于老化，因此不可阻挡似乎是由于不活动造成的。这是可以改变的。

　

　

　

 

其他近期的研究也得出了类似的结论。例如，去年加拿大活动和老龄化中心的研究人员检查了年龄较大的竞技跑步者的肌肉组织，检查他们的运动单位的密度，测量肌肉的健康状况。一个运动单位本质上是一个功能肌肉的控制机制，由一个神经元和那个神经元激活的特定的肌肉纤维组成。肌肉中的运动单位越多，它通常越强壮。

 

在许多早期的研究中，超过50岁的人被发现拥有比年轻人少得多的肌肉运动单位。但对于六十岁以上的跑步者来说，这并不是事实，他们的腿部肌肉几乎和另一组活跃的25岁的人一样多。科学家们写道，跑步似乎能够“减缓老化到生命的第七个十年的运动单位的损失。”

　

　

　

 

当然，莱特博士和加拿大研究的志愿者大部分都是终身运动员。赖特博士说:“在中年或年老时进行锻炼的人是否能获得类似的好处还不清楚，尽管我们没有理由认为，无论何时开始，你都不会得到类似的结果。

 

”在去年的一项令人鼓舞的动物研究中，那些在成年后一直久坐不动的老鼠会被列入跑步计划。13周后，他们的腿部肌肉组织充满了新的肌卫星细胞，这是一种特殊的干细胞，已知可以构建和修复肌肉。不过，在老年人身上进行的类似实验尚未完成。

 

关于运动对老化肌肉的影响的其他问题也没有答案。“我们不知道哪种运动是最好的，”赖特博士说，特别是，耐力锻炼是否对肌肉的锻炼是必要的，或者举重训练是否同样有效。科学家们还没有确定到底需要多少活动才能维持肌肉的质量，或者需要多大的运动量。“我们可以肯定地说，任何活动都比不活动好，”赖特博士说，“而更多的可能比更少更好。”但更重要的信息是，我们的衰老似乎是可以控制的。通过运动，你可以保持肌肉的质量和力量，避免从活力到虚弱的衰退。

 

来源:《纽约时报》。

　

https://s.click.taobao.com/alC3ZMw

https://s.click.taobao.com/31F3ZMw

　

 

NEW RESEARCH SHOWS: MUSCLE LOSS IS NOT INEVITABLE

Source: Reynolds, Gretchen. “Aging Well Through Exercise,” The New York Times. http://well.blogs.nytimes.com/2011/11/09/aging-well-through-exercise/?utm_source=twitterfeed&utm_medium=twitter&utm_campaign=NYT+Wellness 9 November 2011Read New York Times writer Gretchen Reynolds’ article, which describes a new study that reveals how exercise is not an inevitable part of aging:Aging Well Through Exercise

Is physical frailty inevitable as we grow older? That question preoccupies scientists and the middle-aged, particularly when they become the same people. Until recently, the evidence was disheartening. A large number of studies in the past few years showed that after age 40, people typically lose 8 percent or more of their muscle mass each decade, a process that accelerates significantly after age 70. Less muscle mass generally means less strength, mobility and among the elderly, independence. It also has been linked with premature mortality.But a growing body of newer science suggests that such decline may not be inexorable. Exercise, the thinking goes, and you might be able to rewrite the future for your muscles.Consider the results of a stirring study published last month in the journal The Physician and Sportsmedicine. For it, researchers at the University of Pittsburgh recruited 40 competitive runners, cyclists and swimmers. They ranged in age from 40 to 81, with five men and five women representing each of four age groups: 40 to 49, 50 to 59, 60 to 69, and 70-plus. All were enviably fit, training four or five times a week and competing frequently. Several had won their age groups in recent races.They completed questionnaires detailing their health and weekly physical activities. Then the researchers measured their muscle mass, leg strength and body composition, determining how much of their body and, more specifically, their muscle tissue was composed of fat. Other studies have found that as people age, they not only lose muscle, but the tissue that remains can become infiltrated with fat, degrading its quality and reducing its strength.There was little evidence of deterioration in the older athletes’ musculature, however. The athletes in their 70s and 80s had almost as much thigh muscle mass as the athletes in their 40s, with minor if any fat infiltration. The athletes also remained strong. There was, as scientists noted, a drop-off in leg muscle strength around age 60 in both men and women. They weren’t as strong as the 50-year-olds, but the differential was not huge, and little additional decline followed. The 70- and 80-year-old athletes were about as strong as those in their 60s.“We think these are very encouraging results,” said Dr. Vonda Wright, an orthopedic surgeon and founder of the Performance and Research Initiative for Masters Athletes at the University of Pittsburgh Medical Center, who oversaw the study. “They suggest strongly that people don’t have to lose muscle mass and function as they grow older. The changes that we’ve assumed were due to aging and therefore were unstoppable seem actually to be caused by inactivity. And that can be changed.”Other recent studies have produced similar findings. Last year, researchers at the Canadian Centre for Activity and Aging, for instance, examined muscle tissue from older competitive runners, checking for the density of their motor units, a measure of muscle health. A motor unit is, essentially, the control mechanism of a functioning muscle, composed of a neuron and the particular muscle fibers that that neuron activates. The more motor units in a muscle, the stronger it generally is.In multiple earlier studies, people over 50 have been found to possess far fewer muscle motor units than young adults. But that wasn’t true for the sexagenarian runners, whose leg muscles teemed with almost as many motor units as a separate group of active 25-year-olds. Running, the scientists wrote, seemed able to “mitigate the loss of motor units with aging well into the seventh decade of life.”Of course, the volunteers in both Dr. Wright’s and the Canadian study were, for the most part, lifelong athletes. Whether similar benefits are attainable by people who take up exercise when they are middle-aged or older “isn’t yet clear,” Dr. Wright says, “although there’s no reason to think that you wouldn’t get similar results no matter when you start.”In an encouraging animal study from last year, elderly rats that had been sedentary throughout their adult lives were put on a running program. After 13 weeks, their leg muscle tissues had filled with new satellite cells, a specialized type of stem cell that is known to build and repair muscle. Comparable experiments in older people have yet to be done, though.Other questions about the impacts of exercise on aging muscle also remain unanswered. “We don’t know what kinds of exercise are best,” Dr. Wright says and, in particular, whether endurance exercise is necessary for muscle sparing or whether weight training might be as good or better. Scientists also haven’t determined just how much activity is required to maintain muscle mass, or how intense it needs to be.“What we can say with certainty is that any activity is better than none,” Dr. Wright says, “and more is probably better than less. But the bigger message is that it looks as if how we age can be under our control. Through exercise, you can preserve muscle mass and strength and avoid the decline from vitality to frailty.”Source: The New York Times

 

http://aginginmotion.org/news/new-research-shows-muscle-loss-is-not-inevitable/