Editing Sleep inertia (section)

=== Napping ===
When a person is [[Sleep deprivation|sleep deprived]], re-entering sleep may provide a viable route to reduce mental and physical fatigue, but it can also induce sleep inertia. In order to limit sleep inertia, one should avoid waking from the deeper stages of [[slow-wave sleep]]. The onset of slow-wave sleep occurs approximately 30 minutes after falling asleep, therefore a nap should be limited to under 30 minutes to prevent waking during slow-wave sleep and enhancing sleep inertia. Furthermore, self-awakening from a short nap was shown to relieve disorientation of sleep inertia as opposed to a forced awakening, but these results may warrant more research into the nature of arousal after sleep periods.<ref name=":02"/>