ABSTRACT

Objectives: Because African Americans are at elevated risk for cognitive decline and Alzheimer’s disease, it is important to understand which health and lifestyle factors are most important for reducing this risk. Obesity and poor sleep quality are common in lower-income, urban African Americans and have been linked to cognitive decline in older age. Fortunately, increasing aerobic fitness via regular exercise can improve cognitive function. This study sought to (1) examine the cross-sectional relationship between aerobic fitness and cognitive function in older African Americans, and (2) determine whether body mass index and sleep quality moderated the relationship between aerobic fitness and cognition.

Design: 402 older African Americans, ages 60–90 (84% female, mean education level = 14 years) completed neuropsychological testing, computerized behavioral tasks, physical performance measures, and health and lifestyle questionnaires. Hierarchical linear regressions were performed to determine associations between aerobic fitness and cognition and whether body mass index and sleep quality moderate the fitness-cognition relationship while controlling for age, sex, education, depressive symptoms, and literacy.

Results: Higher aerobic fitness levels were significantly associated with better executive function. The relationships between fitness and hippocampal-dependent cognitive functions (learning and memory, generalization) were attenuated in those who are obese (body mass index $\ge$ 30 kg/m²) or rated their sleep quality as poor, ps < .05.

Conclusion: Our results suggest that while exercise and associated improvements in aerobic fitness are key for improved cognition, these benefits are maximized in those who maintain low body weight and get sufficient, high quality sleep. Exercise programs for older African Americans will be most effective if they are integrated with education programs that emphasize healthy eating, weight control, and sleep hygiene and conceptualize individuals as part of their broader social and environmental context.

摘要

目标：由于非裔美国人患认知能力下降和阿尔茨海默病的风险较高，因此了解哪些健康和生活方式因素对于降低这种风险最为重要非常重要。肥胖和睡眠质量差在低收入的城市非洲裔美国人中很常见，并且与老年人的认知能力下降有关。幸运的是，通过定期锻炼增加有氧健身可以改善认知功能。本研究旨在 (1) 检查老年非裔美国人的有氧适能与认知功能之间的横断面关系，以及 (2) 确定体重指数和睡眠质量是否调节有氧适能与认知之间的关系。

设计： 402 名年龄在 60-90 岁之间的年长非裔美国人（84% 为女性，平均教育水平 = 14 岁）完成了神经心理学测试、计算机化行为任务、身体表现测量以及健康和生活方式问卷调查。在控制年龄、性别、教育、抑郁症状和识字率的同时，进行了分层线性回归以确定有氧健身与认知之间的关联，以及体重指数和睡眠质量是否调节健身与认知之间的关系。

结果：更高的有氧健身水平与更好的执行功能显着相关。健康与海马依赖性认知功能（学习和记忆、泛化）之间的关系在肥胖者（体重指数 $\ge$ 30 kg/m ² ) 或认为他们的睡眠质量差，p s < .05。

结论：我们的结果表明，虽然运动和相关的有氧健身改善是提高认知能力的关键，但对于那些保持低体重并获得充足、高质量睡眠的人来说，这些好处会最大化。如果将针对年长非裔美国人的锻炼计划与强调健康饮食、体重控制和睡眠卫生的教育计划相结合，并将个人概念化为更广泛的社会和环境背景的一部分，那么这些计划将是最有效的。