Why hearty women outlive men

The age-old riddle of why many women live longer than men has been solved. It's their pumping power, British researchers have found.

On average, women live five years longer than men and women over the age of 60 are now the fastest-growing section of the British population.

The average male heart becomes weaker with age, and by the age of 70 its power to pump blood around the body could have decreased by up to a quarter of its youthful strength.

David Goldspink, Professor of Cell and Molecular Sports Science at Liverpool John Moores University, said yesterday that women's longevity is linked to the strength of their hearts. Unlike men, they pump just as strongly at 70 as they do at 20.

"We have found that the power of the male heart falls by 20-25 per cent between 18 and 70 years of age," Professor Goldspink said. "In stark contrast, over the same period there was no age-related decline in the power of the female heart, meaning that the heart of a healthy 70-year-old woman could perform almost as well as a 20-year-old's."

The dramatic difference between the sexes might explain why women live longer. The good news is that men of any age can improve the health of their heart simply by taking more regular exercise.

The results are based on the findings of a two-year study of a cross-section of the British population, which examined the effects of ageing on the cardiovascular system.

Professor Goldspink and a team of scientists at the university's Research Unit for Human Development and Ageing examined more than 250 men and women between 18 and 80.

None of the volunteers had a weekly exercise routine and all were considered to have low fitness levels, but were otherwise healthy. Each volunteer underwent five hours of tests to measure their blood pressure and the performance of their heart while at rest and while they exercised on a treadmill.

The researchers found that the large arteries in the body became stiffer and less elastic with age, causing increased blood pressure. Blood flow to the muscles and skin of the limbs was also found progressively to decrease. These changes were found to occur earlier in men, but women caught up soon after the menopause.

长期以来困惑人类的难解之谜——为何多数女性比男性长寿——已经找到了答案。英国研究者们发现，原因在于心脏的供血动力。

女性的平均寿命要比男性多5岁。而目前英国增长速度最快的人群正是60岁以上的女性群体。

一般情况下男性的心脏随着年龄增长而衰老。男性到了70岁时，心脏向全身供血的能力最多可能减少为年轻时的3/4。

昨天（1月10日），利物浦约翰摩尔大学的细胞及分子运动学教授大卫·葛兹平克说，女性的长寿与她们的心脏活力有关。和男性所不同的是，70岁女性的心脏和20岁时一样强健有力。

葛兹平克教授说：“我们已经发现男性在18到70岁之间心脏活力会衰减20%至25%。与之形成鲜明对比的是同年龄范围的女性——没有（任何证据）显示老龄化可导致女性心脏衰弱，这意味着一名健康的70岁老妇和一位20岁女性的心脏几乎可以一样地工作。”

这一巨大的性别差异可能就是女性为何更长寿的答案。所幸的是，任何年龄段的男性都可以改善自己的心脏健康状况，只要他们能更经常地锻炼。

这些结果来源于一项为期两年的研究。该研究对英国人口进行横断面分析，旨在调查年龄增长对心血管系统产生的影响。

葛兹平克教授和一队科学家在（约翰摩尔）大学的人类发展及老龄化研究中心调查了250多名18到80岁的男性和女性。

这些志愿者中无人进行每周固定的体育锻炼，健康状况一般。每位志愿者都进行了5小时的测试，期间检查他们在休息或在跑步机上时的血压和心脏状况。

研究者们发现人体内的大动脉血管随着年龄增长而逐渐僵硬缺少弹性，从而导致血压上升。人体肌肉和四肢皮肤的血液循环也日益减少。这些情况首先出现在男性身上，但女性在绝经后不久也会发生。

Vocabulary:

cross-section: 横断面。研究疾病有一种横断面分析法，主要分析同一时间各年龄组的发病率、患病率和死亡率。

cardiovascular : of, relating to, or involving the heart and the blood vessels（心血管的，侵袭心血管的）

treadmill: an exercise device consisting of an endless moving belt on which a person can walk or jog while remaining in one place（踏车，一种由一根不断运动的皮带组成的锻炼装置，人可以在上面行走，但仍停留在原地）

menopause: the period marked by the natural and permanent cessation of menstruation, occurring usually between the ages of 45 and 55（绝经期，更年期）