一项研究发现，有氧运动能改善老年人的记忆丧失，并且可能阻止衰老过程中的认知衰退。此前的研究已经证明了大脑的海马区在成年期的后期自然地缩小，这削弱了记忆并增加了痴呆的风险。Arthur F. Kramer及其同事研究了对60位55岁到80岁的健康成年人在为期一年的有氧锻炼项目之前、之中和之后的大脑扫描。这组作者报告说，在该研究期间，每周进行3次每次40分钟的行走的受试者的前海马的体积增加了大约2%。参与伸展运动的对照组成员的海马区体积减少了1.4%，这符合正常衰老。
这组科研人员推测，有氧运动提升了来源于脑的神经营养因子在血清中的浓度，神经营养因子是一种天然产生的化合物，它帮助产生新的脑组织并在形成新记忆方面起到关键作用。这组作者说，该研究证明了到成年期的晚期前海马区仍然保持相对活跃状态，而且有氧运动——即便在老年才开始做有氧运动——能够帮助避免与年龄有关的认知衰退。（生物谷Bioon.com）
生物谷推荐英文摘要：
PNAS doi: 10.1073/pnas.1015950108
Exercise training increases size of hippocampus and improves memory
Kirk I. Ericksona, Michelle W. Vossb,c, Ruchika Shaurya Prakashd, Chandramallika Basake, Amanda Szabof, Laura Chaddockb,c, Jennifer S. Kimb, Susie Heob,c, Heloisa Alvesb,c, Siobhan M. Whitef, Thomas R. Wojcickif, Emily Maileyf, Victoria J. Vieiraf, Stephen A. Martinf, Brandt D. Pencef, Jeffrey A. Woodsf, Edward McAuleyb,f, and Arthur F. Kramerb,c,1
The hippocampus shrinks in late adulthood, leading to impaired memory and increased risk for dementia. Hippocampal and medial temporal lobe volumes are larger in higher-fit adults, and physical activity training increases hippocampal perfusion, but the extent to which aerobic exercise training can modify hippocampal volume in late adulthood remains unknown. Here we show, in a randomized controlled trial with 120 older adults, that aerobic exercise training increases the size of the anterior hippocampus, leading to improvements in spatial memory. Exercise training increased hippocampal volume by 2%, effectively reversing age-related loss in volume by 1 to 2 y. We also demonstrate that increased hippocampal volume is associated with greater serum levels of BDNF, a mediator of neurogenesis in the dentate gyrus. Hippocampal volume declined in the control group, but higher preintervention fitness partially attenuated the decline, suggesting that fitness protects against volume loss. Caudate nucleus and thalamus volumes were unaffected by the intervention. These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.
