Daytime napping enhances impulse control

An improvement in impulse control is one of the beneficial effects of nocturnal sleep. Here, we aimed at evaluating whether also napping leads to similar positive effects. Eleven young adults (mean age=25+5 yrs) participated in the study. They underwent a validated Go/NoGo task (Garavan et al. 1999), preceding and following either a NREM nap or its duration-matched control. Each block was preceded by a Psychomotor Vigilance Task (PVT) trial. During the napping session, subjects went to bed around 3 pm and were allowed to sleep for a maximum of one hour. The same subjects underwent also a control session, repeating the two PVT and Go/NoGo blocks, but spending the same time between blocks in quiet waking, rather than sleeping (Control No-Nap Session). During both sessions all subjects were monitored by a 64-Ch EEG system. The performance at the PVT testing was not significantly different in the napping session as compared to the control, indicating that the two conditions were not affected by different degrees of sleep inertia. During the post-nap block subjects showed a significant improvement in the proportion of correct responses when no go stimuli were presented (“correct withholds”, Post-nap mean=0.518+0.267 versus Pre-nap mean=0.383+0.255, p= 0.002) while after the control session no significant improvement was recorded. Our findings reveal a specific positive effect of mid-afternoon NREM napping on impulse control as measured by a standard Go/NoGo task