Department of Physical Activity and Health, The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden.
Department of Neurobiology, Care Sciences and Society, Division of Nursing, Health promotion among children and youth, Karolinska Insitutet, Stockholm, Sweden.
BMC Public Health. 2024 Aug 2;24(1):2090. doi: 10.1186/s12889-024-19306-y.
Physical activity (PA) breaks during school lessons have been suggested as a promising strategy to improve working memory performance in children and adolescents. There is a lack of studies investigating the underlying physiological mechanisms of PA on cognition, especially among adolescents. This study aimed to investigate the effects of different types of short frequent PA on adolescents' cognitive task-related changes in cerebral blood flow in the prefrontal cortex (PFC) and working memory performance compared to prolonged sitting.
In this randomized crossover study, adolescents visited the laboratory on three different occasions for 80-minute sessions of prolonged sitting interrupted by four breaks for three minutes of simple resistance training (SRA), step-up at a pre-determined pace (STEP), or remaining seated (SOCIAL). Before and after each session, cognitive task-related changes in cerebral blood flow (oxygenated-hemoglobin, Oxy-Hb) during working memory tasks (1-, 2-, 3-back tests) were measured using functional near-infrared spectroscopy in the PFC. Accuracy and reaction time were derived from the working memory tasks. Linear mixed-effect models were used to analyze the data.
A total of 17 students participated (mean age 13.6 years, 11 girls). Significant time x condition interactions were noted for Oxy-Hb in the most demanding working memory task (3-back), with a decrease following prolonged sitting in the SOCIAL condition compared to both the SRA (β 0.18, 95% CI 0.12, 0.24) and the STEP (β 0.11, 95% CI 0.05, 0.17). This was observed in parallel with improvements in reaction time following SRA (β -30.11, 95% CI -59.08, -1.13) and STEP (β -34.29, 95% CI -69.22, 0.63) although this was only significant for the SRA and no improvements in the SOCIAL condition.
We found that short frequent PA breaks during prolonged sitting among adolescents can prevent the decrease in cognitive task-related changes in cerebral blood flow that occur following prolonged sitting. This was observed simultaneously with improvements in working memory, indicating that changes in cerebral blood flow could be one factor explaining the effects on working memory. Future studies should investigate the efficacy of implementing these PA breaks in schools.
Retrospectively registered on 21/09/2020, ClinicalTrial (NCT04552626).
在学校课程期间进行体育活动（PA）休息已被提议作为一种改善儿童和青少年工作记忆表现的有前途的策略。目前缺乏研究调查 PA 对认知的潜在生理机制，尤其是在青少年中。本研究旨在调查与长时间坐着相比，不同类型的短而频繁的 PA 对青少年前额叶皮层（PFC）认知任务相关的脑血流变化和工作记忆表现的影响。
在这项随机交叉研究中，青少年在三个不同的场合前往实验室，进行 80 分钟的长时间坐姿，其间穿插 4 次 3 分钟的简单阻力训练（SRA）、预定速度的踏步（STEP）或保持坐姿（SOCIAL）的休息。在每次会议前后，使用功能近红外光谱技术在 PFC 测量工作记忆任务（1-、2-、3-回测试）期间大脑血液流动（氧合血红蛋白，Oxy-Hb）的认知任务相关变化。从工作记忆任务中得出准确性和反应时间。使用线性混合效应模型分析数据。
共有 17 名学生参加（平均年龄 13.6 岁，11 名女孩）。在最具挑战性的工作记忆任务（3-回）中，注意到 Oxy-Hb 存在显著的时间 x 条件交互作用，与 SRA 相比，SOCIAL 条件下长时间坐着后 Oxy-Hb 减少（β 0.18，95%CI 0.12，0.24），与 STEP 相比减少（β 0.11，95%CI 0.05，0.17）。这与 SRA（β -30.11，95%CI -59.08，-1.13）和 STEP（β -34.29，95%CI -69.22，0.63）后反应时间的改善同时发生，尽管这仅在 SRA 中显著，SOCIAL 条件下没有改善。
我们发现，青少年在长时间坐着期间进行短暂而频繁的 PA 休息可以防止长时间坐着后认知任务相关的脑血流变化减少。这与工作记忆的改善同时发生，表明脑血流的变化可能是解释工作记忆影响的因素之一。未来的研究应调查在学校实施这些 PA 休息的效果。
2020 年 9 月 21 日回顾性注册，ClinicalTrial（NCT04552626）。
