Getting a lot of exercise may help slow brain shrinkage in people with early Alzheimer's disease, a preliminary study suggests. Analysis found that participants who were more physically fit had less brain shrinkage than less-fit participants. However, they didn't do significantly better on tests for mental performance.

That was a surprise, but maybe the study had too few patients to make an effect show up in the statistical analysis, said Dr. Jeffrey Burns, one of the study's authors.

He also stressed that the work is only a starting point for exploring whether exercise and physical fitness can slow the progression of Alzheimer's. The study can't prove an effect because the participants were evaluated only once rather than repeatedly over time, he said.

While brains shrink with normal aging, the rate is doubled in people with Alzheimer's, he said.

Burns, who directs the Alzheimer and Memory Program at the University of Kansas School of Medicine in Kansas City, reports the work with colleagues in Tuesday's issue of the journal Neurology.

The study included 57 people with early Alzheimer's. Their physical fitness was assessed by measuring their peak oxygen demand while on a treadmill, and brain shrinkage was estimated by MRI scans.

Dr. Sam Gandy, who chairs the medical and scientific advisory council of the Alzheimer's Association, said the result fits in with previous indications that things people do to protect heart health can also pay off for the brain.

初步的研究建议，多锻炼可以帮助早期阿尔茨海默氏症的患者延缓脑萎缩。分析发现身体更健康的参与者的脑萎缩量比其他参与者的脑萎缩量要小。然而，他们在精神方面的测试上并不突出。

那令人惊奇，可也许这个研究的参与者太少以致不能在统计分析上显出效果来，此次研究的发起人之一，杰弗瑞·伯恩斯博士说。

他还强调这只是探究锻炼和健康的身体是否能延缓阿尔茨海默氏症进程的起点。这次研究并不能证明什么疗效，因为参与者们只被评估了一次而不是多次反复地被评估，他说到。

当大脑因为正常的老化而萎缩时，阿尔茨海默氏症患者的幅度是正常人的两倍，他接着说。

在堪萨斯市堪萨斯大学医学院领导“阿尔茨海默氏症与记忆”项目的伯恩斯在周二的神经病学期刊发布会上与同事一起报告了这项工作。

这项研究包括了57名早期阿尔茨海默氏症患者。他们的身体健康程度通过对他们踏车训练时需氧峰值的测量来评估，脑萎缩通过MRI扫描来评估。

阿尔茨海默氏症协会咨询委员会的医学和科学方面的负责人萨姆·格兰迪博士认为，结果表明之前人们保护心脏的措施也适用于大脑。