Can napping boost productivity and create more hours in the day?

There is no doubt that napping enhances cognitive performance. Harvard researcher Robert Stickgold found that task performance declines during the day, but performance can be fully restored to morning levels after a 90 minute nap — the approximate length of a full sleep cycle with all the stages of sleep. Naps under 90 minutes partially restore performance to morning levels.

Shorter naps are optimal if your time is limited or if you want to avoid sleep inertia, the feeling of tiredness that sometimes appears after waking…