More people are living longer these days, but the good news comes shadowed by the possible increase in cases of age-related mental decline. By some estimates, the global incidence of dementia will more than triple in the next 35 years. That grim prospect is what makes a study published in March in The Journal of Alzheimer's Disease so encouraging: It turns out that regular walking, cycling, swimming, dancing and even gardening may substantially reduce the risk of Alzheimer's.
如今，長壽的人越來越多，但年齡相關性心智衰退病例的增加卻給原本的好消息蒙上了一層陰影。據估計，在未來35年內，全球癡呆症發病率將達到現在的3倍以上。如此可怕的前景當前，今年3月發表在《阿爾茨海默氏症雜誌》(The Journal of Alzheimer's Disease)上的一項研究就顯得格外鼓舞人心了：事實證明，經常散步、騎自行車、游泳、跳舞，甚至是從事園藝工作，都會明顯降低患阿爾茨海默氏症的風險。
Exercise has long been linked to better mental capacity in older people. Little research, however, has tracked individuals over years, while also including actual brain scans. So for the new study, researchers at the University of California, Los Angeles, and other institutions analyzed data produced by the Cardiovascular Health Study, begun in 1989, which has evaluated almost 6,000 older men and women. The subjects complete medical and cognitive tests, fill out questionnaires about their lives and physical activities and receive MRI scans of their brains. Looking at 10 years of data from nearly 900 participants who were at least 65 upon entering the study, the researchers first determined who was cognitively impaired, based on their cognitive assessments. Next they estimated the number of calories burned through weekly exercise, based on the participants' questionnaires.
人們早已發現，在老年人身上，運動與較好的心智功能有關。然而，很少有研究採用腦部掃描等手段對老年人進行長達數年的跟踪。在這項新研究中，加州大學洛杉磯分校(University of California, Los Angeles, UCLA)等機構的研究人員分析了《心血管健康研究》(Cardiovascular Health Study)中產生的數據。該研究始於1989年，評估了近6000名老年男性和女性。受試者們完成了體檢和認知水平測試，填寫了關於他們生活和體育活動的調查問卷，並接受了腦部MRI（磁共振成像）掃描。研究人員查看了近900名在入組時至少年滿65歲的參與者在10年期間的數據，並根據認知評估的結果判定了哪些參與者存在認知障礙。接下來，他們又根據參與者填寫的問卷估算了他們每週運動消耗的卡路里數。
The scans showed that the top quartile of active individuals proved to have substantially more gray matter, compared with their peers, in those parts of the brain related to memory and higher-level thinking. More gray matter, which consists mostly of neurons, is generally equated with greater brain health. At the same time, those whose physical activity increased over a five-year period — though these cases were few — showed notable increases in gray-matter volume in those same parts of their brains. And, perhaps most meaningful , people who had more gray matter correlated with physical activity also had 50 percent less risk five years later of having experienced memory decline or of having developed Alzheimer's.
“For the purposes of brain health, it looks like it's a very good idea to stay as physically active as possible,” says Cyrus Raji, a senior radiology resident at UCLA, who led the study. He points out that “physical activity” is an elastic term in this study: It includes walking, jogging and moderate cycling as well as gardening, ballroom dancing and other calorie-burning recreational pursuits. Dr. Raji said he hopes that further research might show whether this caloric expenditure is remodeling the brain, perhaps by reducing inflammation or vascular diseases.
這項新研究的負責人、加州大學洛杉磯分校放射科住院醫師培訓項目的高年級醫師賽勒斯·拉吉(Cyrus Raji)說：“為了促進大腦的健康，盡可能地積極運動是個好主意。 ”他指出，在這項研究中，“體育活動”一詞的含義相當寬泛：包括散步、慢跑、中速騎自行車、從事園藝工作以及跳交誼舞等多種可以燃燒卡路里的娛樂活動。拉吉博士說，他希望進一步的研究可以揭示出這種熱量消耗是否在通過減少炎症或血管疾病等機制重塑大腦。
The ideal amount and type of activity for staving off memory loss is unknown, he says, although even the most avid exercisers in this group were generally cycling or dancing only a few times a week. Still, the takeaway is that physical activity might change aging's arc. “If we want to live a long time but also keep our memories, our basic selves, intact, keep moving,” Dr. Raji says.
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