Complex sentence: Typically, sleep inertia lasts between 15 and 20 minutes for a night wake up and 5-10 minutes for a day wake up though if the person was awakened due to a perceived danger it is reduced to only a few seconds.
Split into simpler sentences: Typically, sleep inertia lasts between 15 and 20 minutes for a night wake up and 5-10 minutes for a day wake up. If the subject is awakened due to a perceived danger, however, the duration of sleep inertia is reduced to only a few seconds.