Humans age dramatically at two key points in their life, study finds
研究发现，人类在人生的两个关键阶段会急剧衰老
Scientists have found that human beings age at a molecular level in two accelerated bursts – first at the age of 44, and then again at 60.
科学家们发现，人类会在分子层面上经历两次显著的衰老过程——首先是44岁，然后是60岁。
In a study published in the journal Nature Aging, scientists at Stanford University and Nanyang Technological University in Singapore followed 108 participants over several years to observe aging changes in their molecules — RNA, proteins and participants' microbiomes.
在《自然·衰老》期刊上发表的一项研究中，斯坦福大学和新加坡南洋理工大学的科学家团队对108名参与者进行了多年的跟踪调查，以深入探究他们体内分子的老化过程如RNA、蛋白质和参与者的微生物组。
The scientists found that human aging does not happen in a gradual, linear way. Rather, the majority of the molecules they studied showed accelerated, non-linear changes at the ages of 44 and 60.
科学家们发现，人类衰老并非以渐进、线性的方式逐步进行。相反，他们所研究的大多数分子在44岁和60岁时都经历了加速、非线性的转变。
Xiaotao Shen, an assistant professor in microbiome medicine at Nanyang Technological University and first author of the study, says that the results show "we are not becoming old gradually." Some points in time are particularly important for our aging and health, he added.
南洋理工大学微生物组医学助理教授、该研究的第一作者沈小涛表示，研究结果显示“我们的衰老过程并非平稳渐进”。他进一步指出，生命过程中的某些关键时点对我们的衰老进程及健康状况有显著影响。
For example, the ability to metabolize caffeine notably decreases – first around the age of 40 and once more around 60. Components involved in metabolizing alcohol also diminish, particularly around the age of 40, Michael Snyder, chair of the department of genetics at Stanford and an author of the study, told CNN, referring to the two waves of aging.
例如，人体代谢咖啡因的能力会显著下降——第一次大约是在40岁左右，然后是在60岁左右。斯坦福大学遗传学系主任兼该研究作者迈克尔·斯奈德在谈到这两波衰老期时告诉美国有线电视新闻网，参与酒精代谢的组分也会减少，尤其是大约40岁左右的时候。
Snyder added that, "people often get muscle injuries and see their fat accumulation hit in their 40s (related to lipid metabolism), and definitely sarcopenia (muscle loss) hit people in their 60s — this is a very big deal."
斯奈德补充道：“人们经常在40多岁时出现肌肉损伤和脂肪堆积（与脂质代谢有关），60多岁时肌肉流失（肌少症）的情况也更为严重——这是一个非常严重的问题。”
Both age groups experienced changes in proteins which hold tissues together, which likely helps explain skin, muscle and cardiovascular changes, he added. Disease risks also rise faster, particularly after the age of 60. The study found that people age 60 or older are more susceptible to cardiovascular disorders, kidney issues and type 2 diabetes.
他补充说，这两个年龄段的人群都经历了结合蛋白质的变化，这有助于解释皮肤、肌肉和心血管的变化。特别是60岁之后，患病几率大大增加。研究发现，60岁及以上的人更容易得心血管疾病、肾脏疾病以及2型糖尿病。
Finding patterns like these can help with the diagnosis and prevention of diseases, according to the study, which said it had also identified "clinically actionable markers" that can be used to improve health-care management and the well-being of aging populations.
根据这项研究，发现这些模式有助于疾病的诊断和治疗，该研究还指出，已经确定了“可临床操作的标志物”，这些标志物可用于改善医疗保健管理和老年人口的生活质量。
The study focused on participants between the ages of 25 and 75 for nearly two years, on average. Participants all lived in California, were healthy and came from diverse ethnic backgrounds. Samples of blood, stool, skin and nasal and oral swabs were taken from them every three to six months.
近两年来，该研究大致追踪了25至75岁的参与者。所有实验参与者都住在加利福尼亚州，身体健康，来自不同的种族。每三到六个月对他们进行血液、粪便、皮肤以及鼻拭子和口腔拭子样本取样。
Since accelerated aging in women could have been attributed to menopause (which is typically between ages 45 and 55), the researchers performed analysis on separate male and female datasets. To their surprise, they found the results were similar –suggesting a transition point around 55 could be a common phenomenon for both sexes.
由于女性的加速衰老可能与更年期（通常发生在45至55岁之间）有关，因此，研究人员分别对男性和女性的数据进行了分析。令人惊讶的是，他们发现结果相似——这表明大约55岁左右的过渡期可能是男性和女性的共同现象。
A previous study by researchers in Germany and the United States had found that there is another "wave" of aging around 75, but the latest research was not able to confirm those findings because of the limited age range of the cohort in the trial, Shen says.
德国和美国研究人员在之前的一项研究中发现，大概75岁时会出现另一波衰老，沈博士表示，由于试验中受试者的年龄范围受限，最新研究无法证实这些结论。
As for what to take away from their findings, the researchers advise making lifestyle changes such as drinking less alcohol and exercising more when nearing these pivotal years in your 40s and 60s.
关于如何从这些发现中获益，研究人员建议，在接近40岁和60岁这些关键年龄时，要改变生活方式，比如少喝酒、多运动。
Snyder advised people approaching their 60s to watch their carb intake and drink plenty of water to aid kidney function. "Take care of yourself more closely at specific time points during your life span," advised Shen.
斯奈德建议快60岁的人要控制碳水化合物的摄入量，多喝水增强肾功能。沈博士建议道：“在你生命的特定时间点要更加关注自己的健康。”
苏格拉底有一句名言：我知我无知。说的是，当你认识到的东西越多就越发现自己无知。苏格拉底认为，人对于客观世界的认识是有限的，且不可能完全认识客观世界，并且不应对客观世界刨根究底。神对于世界的规划自有安排，若人一意孤行地探索世界和自然的奥秘，则最终将亵渎甚至触怒神明。正因为人对神所构建的世界不可能实现完全认知，因此那些宣称自己能够认识和改造世界的人，本身便是无知的代言。尽管苏格拉底的关于“ 我知我无知”的观念的解读，在现在看来有失客观科学。但至少苏格拉底告诫人们，人的认知是有限的，现有的知识甚至可能存在错误和疏漏。因此，无论任何时代，我们都必须对自己的无知加以认识并通过不懈的开拓，去更新甚至颠覆固有的知识结构。我们在求学之路上也要报以我知我不知的心态，才能走得更远、终有所成。最后，祝愿每一位考研学子都能顺利上岸！
