Physical activity has positive effects on brain health and cognitive function throughout the life span. Thus far, few studies have examined the effects of physical activity on white matter microstructure and psychomotor speed within the same, population-based sample (critical if conclusions are to extend to the wider population). Here, using diffusion tensor imaging and a simple reaction time task within a relatively large population-derived sample (N = 399; 18-87 years) from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN), we demonstrate that physical activity mediates the effect of age on white matter integrity, measured with fractional anisotropy. Higher self-reported daily physical activity was associated with greater preservation of white matter in several frontal tracts, including the genu of corpus callosum, uncinate fasciculus, external capsule, and anterior limb of the internal capsule. We also show that the age-related slowing is mediated by white matter integrity in the genu. Our findings contribute to a growing body of work, suggesting that a physically active lifestyle may protect against age-related structural disconnection and slowing.

中文翻译：

---

体育锻炼可预测额叶白质与人群水平相关的年龄差异。

在整个生命周期中，体育锻炼对大脑健康和认知功能都有积极影响。到目前为止，很少有研究在相同的，以人群为基础的样本中检验体育活动对白质微结构和精神运动速度的影响（如果结论要延伸到更广泛的人群，则至关重要）。在这里，通过使用扩散张量成像和来自剑桥老龄与神经科学中心（Cam-CAN）的相对较大的人群衍生样本（N = 399； 18-87岁）中的简单反应时间任务，我们证明了体育活动可以介导年龄对白质完整性的影响，用分数各向异性来衡量。自我报告的较高的日常体育活动与一些额叶中白质的更好保存相关，包括call体属，束状筋膜，外囊和内囊的前肢。我们还表明，与年龄相关的减慢是由该种属中的白质完整性介导的。我们的发现有助于不断发展的工作，这表明体育锻炼的生活方式可以防止与年龄有关的结构分离和减慢。