The prevalence of cognitive impairment and dementia is expected to increase dramatically as the population ages, creating burdens on families and health care systems.

To assess the effectiveness of physical activity interventions in slowing cognitive decline and delaying the onset of cognitive impairment and dementia in adults without diagnosed cognitive impairments.

Several electronic databases from January 2009 to July 2017 and bibliographies of systematic reviews.

Trials published in English that lasted 6 months or longer, enrolled adults without clinically diagnosed cognitive impairments, and compared cognitive and dementia outcomes between physical activity interventions and inactive controls.

Extraction by 1 reviewer and confirmed by a second; dual-reviewer assessment of risk of bias; consensus determination of strength of evidence.

Of 32 eligible trials, 16 with low to moderate risk of bias compared a physical activity intervention with an inactive control. Most trials had 6-month follow-up; a few had 1- or 2-year follow-up. Evidence was insufficient to draw conclusions about the effectiveness of aerobic training, resistance training, or tai chi for improving cognition. Low-strength evidence showed that multicomponent physical activity interventions had no effect on cognitive function. Low-strength evidence showed that a multidomain intervention comprising physical activity, diet, and cognitive training improved several cognitive outcomes. Evidence regarding effects on dementia prevention was insufficient for all physical activity interventions.

Heterogeneous interventions and cognitive test measures, small and underpowered studies, and inability to assess the clinical significance of cognitive test outcomes.

Evidence that short-term, single-component physical activity interventions promote cognitive function and prevent cognitive decline or dementia in older adults is largely insufficient. A multidomain intervention showed a delay in cognitive decline (low-strength evidence).

Agency for Healthcare Research and Quality.

随着人口的老龄化，认知障碍和痴呆症的患病率预计将急剧上升，给家庭和医疗保健系统造成负担。

评估体育活动干预措施在未诊断为认知功能障碍的成年人中减缓认知能力下降和延迟认知功能障碍和痴呆症发作的有效性。

从2009年1月到2017年7月的几个电子数据库，以及系统评价的书目。

以英语发表的为期6个月或更长时间的试验，招募了没有临床诊断为认知障碍的成年人，并比较了体育锻炼与非活动性对照之间的认知和痴呆结局。

由1位审稿人提取并经第二次确认；双重审查者对偏见风险的评估；共识确定证据的力量。

在32项符合条件的试验中，有16项具有低至中度偏倚风险的试验将体育锻炼与无活动对照进行了比较。大多数试验进行了6个月的随访。一些人进行了1年或2年的随访。证据不足以得出关于有氧训练，阻力训练或太极拳对提高认知能力的有效性的结论。低强度的证据表明，多成分的体育锻炼干预对认知功能没有影响。低强度证据表明，包括体育锻炼，饮食和认知训练在内的多领域干预措施可以改善一些认知结果。关于预防痴呆症的作用的证据不足以用于所有体育锻炼干预措施。

异构干预措施和认知测试方法，规模较小且研究不足的研究以及无法评估认知测试结果的临床意义。

短期，单一成分的体育锻炼干预措施可促进老年人的认知功能并防止认知能力下降或痴呆的证据在很大程度上是不足的。多领域干预显示出认知能力下降的延迟（低强度证据）。

医疗保健研究与质量局。