Walk, Jog or Dance: It’s All Good for the Aging Brain
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，长寿的人越来越多，但年龄相关性心智衰退病例的增加却给原本的好消息蒙上了一层阴影。据估计，在未来35年内，全球痴呆症发病率将达到现在的3倍以上。如此可怕的前景当前，今年3月发表在《阿尔茨海默氏症杂志》(The Journal of Alzheimer’s Disease)上的一项研究就显得格外鼓舞人心了：事实证明，经常散步、骑自行车、游泳、跳舞，甚至是从事园艺工作，都会明显降低患阿尔茨海默氏症的风险。
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 M.R.I. 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.
人们早已发现，在老年人身上，运动与较好的心智功能有关。然而，很少有研究采用脑部扫描等手段对老年人进行长达数年的跟踪。在这项新研究中，加州大学洛杉矶分校(University of California, Los Angeles, U.C.L.A.)等机构的研究人员分析了《心血管健康研究》(Cardiovascular Health Study)中产生的数据。该研究始于1989年，评估了近6000名老年男性和女性。受试者们完成了体检和认知水平测试，填写了关于他们生活和体育活动的调查问卷，并接受了脑部M.R.I.（磁共振成像）扫描。研究人员查看了近900名在入组时至少年满65岁的参与者在10年期间的数据，并根据认知评估的结果判定了哪些参与者存在认知障碍。接下来，他们又根据参与者填写的问卷估算了他们每周运动消耗的卡路里数。
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 U.C.L.A., 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.
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.