How long of a nap can significantly help reduce drowsiness while driving?

A short nap of 10 to 20 minutes is most effective in reducing drowsiness while driving because it allows you to experience light sleep without entering deeper sleep stages, which can leave you feeling groggy and more fatigued upon waking. This duration is sufficient to improve alertness, focus, and reaction times without resulting in sleep inertia, the groggy feeling that can occur when waking from longer naps.

Extending the nap to durations longer than 20 minutes may lead you into deeper sleep stages, which can be counterproductive when trying to combat drowsiness. While longer naps, such as 30 to 60 minutes or even up to 1 to 2 hours, may provide more restorative benefits, they significantly increase the risk of waking up feeling disoriented and sluggish, making it harder to resume alertness needed for driving safely. Thus, the 10 to 20-minute nap strikes the right balance for immediate drowsiness reduction while ensuring you remain sharp and ready to drive.