步行速度越快的人寿命越长?

In an analysis that included data from 9 studies, having higher measures of walking speed among older adults was associated with increased length of survival, according to a study in the January 5 issue of JAMA.

刊登在1月5日的美国医学会杂志(JAMA)上的一篇研究报告称，步行速度较快的老人寿命较长。

"Remaining years of life vary widely in older adults, and physicians should consider life expectancy when assessing goals of care and treatment plans. However, life expectancy based on age and sex alone provides limited information because survival is also influenced by health and functional abilities," according to background information in the article. There are currently no well-established approaches to predicting life expectancy that incorporate health and function. Gait speed, or walking speed, has been recommended as a potentially useful clinical indicator of well-being among older adults.

背景资料：老年人的寿命长短差异很大，医生在评估保健及治疗方案的目标时应该将预期寿命纳入考虑范围，但仅建立在年龄与性别基础上的预期寿命并不十分准确，因为健康与身体机能也会影响寿命的长短。但是，目前的预期寿命预测方法全都没有将健康与身体机能涵盖其中。

Stephanie Studenski, M.D., M.P.H., of the University of Pittsburgh, and colleagues conducted a study to assess the association of gait speed with survival in older adults and to determine the degree to which gait speed explains variability in survival after accounting for age and sex. The study included a pooled analysis of 9 participating studies (collected between 1986 and 2000), using individual data from 34,485community-dwelling adults age 65 years or older with walking speed data available at the beginning of the study, followed up for 6 to 21 years. Participants had an average age of 73.5 years; 59.6 percent were women; and 79.8 percent were white. Gait speed wascalculated for each participant using distance in meters and time in seconds. All studies used instructions to walk at usual pace and from a standing start. The walk distance varied from 8 feet to 6 meters. The average gait speed of the participants was 0.92 meters (3 feet) per second.

进行该项研究的是匹兹堡大学的公共卫生学硕士及医学博士斯蒂芬妮和她的同事们，该研究旨在揭示老年人步速与寿命之间的关联，并借此确定步速对寿命的影响程度。研究的原始资料包括来自9个研究项目的数据分析，这些数据是在1986年到2000年间收集得来的，而研究对象为34485名65岁或以上的老年人。研究人员对这些老年人的步速进行长达数年的跟踪记录，所有记录均遵循两个原则：1.测量的是日常步行速度;2.从站立状态开始步行。数据显示，研究对象的平均寿命为73.5岁，平均步速则为0.92米/秒。

During the course of the study, there were 17,528 deaths. The overall 5-year survivalrate was 84.8 percent; the 10-year survival rate was 59.7 percent. The researchers found that gait speed was associated with differences in the probability of survival at all ages in both sexes, but was especially informative after age 75 years. At this age,predicted 10-year survival across the range of gait speeds ranged from 19 percent to 87 percent in men and from 35 percent to 91 percent in women.

在研究进行期间，有17528名老人去世。其中，从研究开始时算起，有5年或以上剩余寿命的老人约占84.8%，而有10年或以上剩余寿命的则占59.7%。研究人员发现，年龄相同、性别一致的老年人，其剩余寿命与步行速度有关，这在75岁以上的老年人群体里尤为明显。

"Predicted years of remaining life for each sex and age increased as gait speed increased, with a gait speed of about 0.8 meters [2.6 feet]/second at the median [midpoint] life expectancy at most ages for both sexes. Gait speeds of 1.0 meter [3.3 feet]/second or higher consistently demonstrated survival that was longer than expected by age and sex alone. In this older adult population the relationship of gait speed with remaining years of life was consistent across age groups, but the absolute number of expected remaining years of life was larger at younger ages," the authors write.

在大多数年龄段中，寿命为预期寿命中值的老年人，其步速约为0.8米/秒，男女皆是如此;而在性别与年龄一致的前提下，步行速度越快，其预期寿命越长。步速达1米/秒以上的老年人，其预期寿命会比只考虑年龄与性别时的预期要长。在多个年龄组别中，老年人的步速与剩余寿命均成正比关系，而且年纪越小，其预期剩余寿命的绝对值越大。

The authors suggest there are several reasons why gait speed may predict survival. "Walking requires energy, movement control, and support and places demands on multiple organ systems, including the heart, lungs, circulatory, nervous, and musculoskeletal systems. Slowing gait may reflect both damaged systems and a high energy cost of walking."

为什么步速能预测寿命呢?这是由于步行需要耗费身体能量并对肢体动作进行有效的控制，同时还需要包括心肺系统、循环系统、神经系统以及肌肉骨骼系统在内的多个器官系统的支持与配合。步行速度慢一方面反映出老人的身体系统已经受损，另一方面也表明他/她步行时需要耗费较多的能量，所以步速能对老人的寿命起到预示的作用。

The researchers write that there are a number of ways gait speed might be used clinically, including helping to identify older adults with a high probability of living for 5 or 10 more years, who may be appropriate targets for preventive interventions that require years for benefit. Gait speed might be used to identify older adults with increased risk of early mortality, perhaps those with gait speeds slower than 0.6 meter (2 feet)/second. "In these patients, further examination is targeted at potentially modifiable risks to health and survival." Also, gait speed might be monitored over time, with a decline indicating a new health problem that requires evaluation.

研究人员表示，步速在临床上具有很广泛的作用，包括有助于确定哪些人群会有5年或10年以上的剩余寿命，哪些人群早逝的风险更大。针对早逝风险大的人群，我们可以对他们进行进一步的体检以确定其健康问题，从而有针对性地对其进行治疗。另外，对步速进行长期监控有助于发现身体出现的新问题。

"The data in this article can be used to help interpret the results. Gait speed may be a simple and accessible indicator of the health of the older person," the authors conclude.

总而言之，步速是老年人健康的一个简单而且易得的指标，有助于医生、研究人员以及医疗体系决策者确定老年人的健康状况以及寿命。