Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA.
Mayo Clin Proc. 2011 Sep;86(9):876-84. doi: 10.4065/mcp.2011.0252.
A rapidly growing literature strongly suggests that exercise, specifically aerobic exercise, may attenuate cognitive impairment and reduce dementia risk. We used PubMed (keywords exercise and cognition) and manuscript bibliographies to examine the published evidence of a cognitive neuroprotective effect of exercise. Meta-analyses of prospective studies documented a significantly reduced risk of dementia associated with midlife exercise; similarly, midlife exercise significantly reduced later risks of mild cognitive impairment in several studies. Among patients with dementia or mild cognitive impairment, randomized controlled trials (RCTs) documented better cognitive scores after 6 to 12 months of exercise compared with sedentary controls. Meta-analyses of RCTs of aerobic exercise in healthy adults were also associated with significantly improved cognitive scores. One year of aerobic exercise in a large RCT of seniors was associated with significantly larger hippocampal volumes and better spatial memory; other RCTs in seniors documented attenuation of age-related gray matter volume loss with aerobic exercise. Cross-sectional studies similarly reported significantly larger hippocampal or gray matter volumes among physically fit seniors compared with unfit seniors. Brain cognitive networks studied with functional magnetic resonance imaging display improved connectivity after 6 to 12 months of exercise. Animal studies indicate that exercise facilitates neuroplasticity via a variety of biomechanisms, with improved learning outcomes. Induction of brain neurotrophic factors by exercise has been confirmed in multiple animal studies, with indirect evidence for this process in humans. Besides a brain neuroprotective effect, physical exercise may also attenuate cognitive decline via mitigation of cerebrovascular risk, including the contribution of small vessel disease to dementia. Exercise should not be overlooked as an important therapeutic strategy.
越来越多的文献表明，运动，特别是有氧运动，可能减缓认知障碍的发展，降低痴呆症的发病风险。我们使用 PubMed（关键词为“运动”和“认知”）和文献的参考文献，来检查运动对认知具有神经保护作用的已发表证据。前瞻性研究的荟萃分析记录到，与中年运动相关的痴呆症风险显著降低；同样，在几项研究中，中年运动也显著降低了轻度认知障碍的后期风险。在痴呆症或轻度认知障碍患者中，随机对照试验（RCT）记录到，与久坐不动的对照组相比，经过 6 至 12 个月的运动后认知评分更好。对健康成年人进行的有氧运动 RCT 的荟萃分析也与认知评分的显著改善相关。在一项针对老年人的大型 RCT 中，进行一年的有氧运动与海马体体积显著增大和空间记忆改善有关；其他针对老年人的 RCT 记录到，有氧运动可以减轻与年龄相关的灰质体积损失。横断面研究同样报告称，与身体不适应的老年人相比，身体状况良好的老年人的海马体或灰质体积更大。进行 6 至 12 个月的运动后，大脑认知网络的功能磁共振成像显示出连接性得到改善。动物研究表明，运动通过多种生物力学机制促进神经可塑性，从而改善学习成果。多项动物研究证实了运动诱导脑源性神经营养因子的作用，而人类也有间接证据支持这一过程。除了对大脑具有神经保护作用外，身体锻炼还可以通过减轻脑血管风险（包括小血管疾病对痴呆的影响）来减缓认知能力下降。作为一种重要的治疗策略，运动不应被忽视。
