Department of Aerospace Medicine, Air Force Medical University, Xi'an, China.
Department of Medical Genetics and Developmental Biology, Air Force Medical University, Xi'an, China.
Front Public Health. 2022 Oct 10;10:922716. doi: 10.3389/fpubh.2022.922716. eCollection 2022.
Night shifts have adverse cognitive outcomes that might be attenuated by daytime napping. The neurovisceral integration model suggests that resting vagally mediated heart rate variability (vmHRV) is linked with cognitive function. This study investigated the relationship between resting vmHRV and cognitive function after different nap durations in interns after shift work.
A total of 105 interns were randomly allocated to one of three groups (non-nap, = 35; 15-min nap, = 35; 45-min nap, = 35) to perform cognitive tests and resting vmHRV at 12:00, 15:00 and 18:00. Information processing (digit symbol substitution test; DSST), motor speed (finger tapping test; FTT), response selection (choice reaction time; CRT), and attention shifts (shifting attention test; SAT) were assessed. Resting vmHRV was assessed at baseline and during each cognitive task across groups.
Compared with the non-nap control, the 15-min and 45-min naps improved all outcome measures (including subjective sleepiness and cognitive performance) at 15:00, with some benefits maintained at 18:00. The 15-min nap produced significantly greater benefits on the FTT at 15:00 after napping than did the 45-min nap. Resting vmHRV was significantly correlated with DSST and SAT performance. In addition, FTT performance was the only significant predictor of DSST performance across different nap durations.
Our results demonstrate links between daytime napping (in particular, a 15-min nap) and improved cognitive control in relation to autonomic activity after shift work in interns. These results indicated that autonomic activity when awake plays a crucial role in DSST and SAT performance and facilitated the understanding of differences in neurocognitive mechanisms underlying information processing after different nap durations.
夜班对认知有不良影响，白天小睡可能会减轻这种影响。神经内脏整合模型表明，静息时迷走神经介导的心率变异性（vmHRV）与认知功能有关。本研究调查了轮班后内科住院医师在不同小睡时间后静息 vmHRV 与认知功能之间的关系。
共有 105 名住院医师被随机分配到三组之一（无小睡组，n = 35；15 分钟小睡组，n = 35；45 分钟小睡组，n = 35），以在 12:00、15:00 和 18:00 时进行认知测试和静息 vmHRV。评估信息处理（数字符号替代测试；DSST）、运动速度（手指敲击测试；FTT）、反应选择（选择反应时；CRT）和注意力转移（转移注意力测试；SAT）。在各组中，在基线和每次认知任务期间评估静息 vmHRV。
与无小睡对照组相比，15 分钟和 45 分钟小睡在 15:00 时改善了所有结果指标（包括主观困倦和认知表现），并在 18:00 时保持了一些益处。与 45 分钟小睡相比，15 分钟小睡在小睡后 15:00 时显著提高了 FTT 的表现。静息 vmHRV 与 DSST 和 SAT 表现显著相关。此外，FTT 表现是不同小睡时间下 DSST 表现的唯一显著预测因素。
我们的结果表明，在轮班后，白天小睡（特别是 15 分钟小睡）与认知控制的改善有关，与自主活动有关。这些结果表明，清醒时的自主活动在 DSST 和 SAT 表现中起着至关重要的作用，并有助于理解不同小睡时间后信息处理的神经认知机制的差异。
