What is the approximate alertness restoration from a 15-20 minute nap?

A 15-20 minute nap is effective for a brief restoration of alertness and cognitive performance. Research indicates that this duration of napping is ideal for reducing sleep inertia and enhancing immediate alertness without leading to grogginess that can sometimes follow longer periods of sleep.

The sleep cycle typically includes multiple stages, and a short nap allows a person to rest without entering deeper stages of sleep. This limited sleep isn’t enough to allow for extensive regeneration and recovery found in longer naps, which could last into the deeper sleep stages and consequently bring longer alertness restoration.

Although a short nap can help improve alertness, it is typically closer to 1-2 hours of improved alertness rather than 3-4, 5-6, or even 7-8 hours, which would imply a level of rest typically associated with a full night's sleep rather than a quick power nap. Thus, while a longer nap may provide extended periods of alertness, the specific time frame from a 15-20 minute nap aligns more accurately with a restoration of about 1-2 hours.