英語聽力文摘 人類何以長壽？

Long Live Us

About a century ago, the average life-span for Americans was about 50 years. Today, the typical American lives for around seventy-eight years.

According to a German aging study, the maximum life span in industrialized countries has increased by two years every decade since the mid 19th century. What accounts for such increased longevity?

Between 1900 and 1950, inventions such as refrigeration and sewage treatment meant that young people were able to survive longer. Moreover, medical breakthroughs helped contain diseases such as polio, which killed many children. These advances helped increase the average life span.

Medical discoveries after World War II tended to benefit older people. Treatments for heart disease, for example, have allowed the elderly to live longer on average. So does this mean that future medical breakthroughs will result in even longer average life spans, or have we reached our limit? Scientists disagree.

Some argue that if science is one day able to eradicate disease and old-age infirmity, there will be virtually no limit on how long humans can live. Some even predict that by the year 2150, the average life span will have increased to around 120 years.

Other life-expectancy researchers find that scenario highly unlikely. Our bodies’ cells can keep reproducing for only so long before they peter out. Only when science finds a way to keep our cells dividing longer will we see another significant leap in life expectancy.

Still, with plenty of exercise and a healthy diet, those so inclined can always hope that they’ll live long enough to break the record held by Jeanne Louise Calment of France, who lived to be 122.

人類萬歲

約一個世紀以前，美國的人均壽命是50歲左右。如今，美國一般都能活到78歲左右。

德國一項關于壽命的研究指出，19世紀中葉以來工業(yè)化國家人口的最高壽命增長迅速——每十年人們的最高壽命就會增長兩歲。是什么讓人們的壽命增長的如此之快呢?

1900年至1950年期間，制冷技術及污水處理的發(fā)明便意味著年輕的一代能活得更久。再者，醫(yī)療水平的重大突破對一些疾病起到了很好的控制作用，例如奪去許多兒童生命的小兒麻痹癥。社會的這些進步都有助于提高人類的平均年齡。

二戰(zhàn)后的科學研究都傾向于“造福”老年群體。就拿對心臟病的治療來說，就大大提高了老年人的平均壽命。那我們是不是就可以由此推出——日后的醫(yī)學突破將會使人類的平均壽命再得到延長，或是，人類已經(jīng)達到了生命的極限?科學家對此持否定看法。

有人認為，如果科學能夠消除一切疾病以及年老體衰，那么人類的壽命就沒有了限度。更有甚者，有人預測到2150年，人類的平均壽命將會達到驚人的120歲。

其他的壽命研究人員認為這樣的假設是不可能的。人體細胞只能在細胞數(shù)量逐漸減少前不斷進行復制。除非科學家們找到方法延長細胞分裂時間，人類的平均壽命才可能再有一次突飛猛進。

當然，那些贊成此種觀點的人也可以懷抱這樣的一份希望——堅持鍛煉，養(yǎng)成健康的飲食習慣，打破法國Jeanne Louise Calment老人122歲的長壽記錄。