Power Napping. Benefits of Power napping: effects on your alertness, productivity and personal effectiveness.
Generally, people can only lap in the daytime when they have a sufficiently large sleep debt and the brain is not strongly alerted by the biological brain. Naps are generally defined as periods of sleep ranging from five minutes to four hours; any less would be considered a microsleep, any more would be too long to be considered a nap.
As Dement notes, there are different types of naps for different purposes: the emergency nap used to cope with drowsiness in dangerous situations; the preventative nap when taken in anticipation of having to stay up late; the habitual nap.
Famous people who napped a lot
Lyndon Johnson would put on his pajamas in the middle of the day and nap for half an hour in order to work longer hours, while Winston Churchill would nap during the day so he could work late into the night.
Benefits of Napping
Midday Dip in Alertness
Naps are an excellent way to counteract the midday dip in alertness, which is the lull between the morning period of clock dependent alerting and the evening period of clock dependent alerting. Hence, naps are most efficient during the midday nap in alertness; napping at other times would likely be inefficient.
Research has proven that strategic naps can improve performance and measurably increase subsequent alertness. In general, the longer the nap, the greater the benefit. These benefits are usually long-lasting. In fact, the researchers at Stanford found that merely a 45-minute nap would improve alertness for 6 hours after a nap; other research suggests that a 1-hour nap would improve alertness for 10 hours after the nap.
Napping improves performance and productivity
Interestingly, Dement found that napping improves objective performance more than subjective performance. That essentially means that while you might not any different after a nap, objective measurements would prove that your performance did improve. He suggests that this might be because of the sleep inertia that lasts for approximately 15 minutes after a nap, when you might feel groggy and experience lower performance; performance generally increases after you pass this initial period.