Abstract
Midafternoon sleepiness frequently occurs independently of lunch or lack of sleep, suggesting an association with biological rhythms. One effective strategy to counteract this sleepiness is taking a nap. However, naps exceeding one hour can increase the risk of various health issues and cause grogginess upon awakening, known as sleep inertia. Additionally, lengthy naps often disrupt nighttime sleep. These adverse effects arise from the occurrence of slow-wave sleep (Sleep Stage N3) during the nap. In contrast, short naps lasting approximately 15 to 20 minutes can avoid slow-wave sleep, thereby minimizing adverse effects and enhancing benefits such as decreased sleepiness and improved performance. Although short naps primarily involve sleep stages N1 and N2, only N2 contributes to the restorative benefits of napping, with N1 providing minimal effectiveness. Nevertheless, sleep inertia can still occur after short naps. Several countermeasures are explored to mitigate this inertia, such as arousal stimuli, caffeine intake, or self-awakening techniques.
