Power nap

A power-nap (sometimes called a catnap) is a short sleep, usually 15-20 minutes, intended to revitalize the subject from drowsiness while working, coined by Cornell University social psychologist James Maas.

Characteristics
Power napping is thought by many to maximize the benefits of sleep versus time. This type of sleep pattern may be associated with polyphasic sleep; however, it is more often used to supplement normal sleep, especially when the sleeper has accumulated a sleep deficit.

Advocates of this sleep pattern recommend various durations for a power-nap. Many have a precise time which they say is optimal - usually around 20-35 minutes. People who regularly take power-naps usually have a good idea of what duration works best for them, as well what environment, position, and associated factors help induce the best results. Some people take power naps out of necessity. For example, someone who doesn't get enough sleep at night and is drowsy at work may sleep during his or her lunch break. Others may prefer to regularly take power naps even if their schedule allows a full night's sleep. Importantly, napping skills are trainable and have been shown to become more efficient in more experienced nappers.

Normally, the short duration of a power-nap prevents nappers from entering Slow-wave sleep. Anecdotally, some say that waking up after a person has entered this deeper state of sleep can result in a phenomenon known as sleep inertia, perhaps causing the person to feel groggy. Research has shown, however, that splashing water on one's face, brief exercise or a shot of caffeine can help decrease the ill effects of sleep inertia. Other people have said that careful training, or with use of assistive audio products can allow them to experience a well-rested, rejuvenating experience from a power-nap.

Difference between a power-nap and a catnap
While a power-nap and a catnap can be considered to be synonymous in terms of duration and effect, the vernacular usage often makes a behavioral distinction where a power-nap involves a break from activity, while a catnap is of a more leisurely nature. Thus, one may take a power-nap in the middle of a busy work day, and a catnap on the couch during a lazy afternoon, but not vice versa.

Benefits
Scientists have recently begun investigating the benefits of napping for performance across a wide range of cognitive processes. Since these seminal studies demonstrated that naps were as good as a night of sleep on some memory tasks, more sleep laboratories have reported similar results. A NASA study has found, however, that while naps improve memory functions, they do not aid basic alertness.

Power-naps in different cultures
Many cultures have recognized and promoted the benefits of daily naps, including the tradition of the siesta in Spain and Latin America. In the Australian state of Victoria, the Transport Accident Commission has invested in advertising campaigns, advising drivers to take a "15 minute power-nap" to help reduce the risk of fatigue when operating a motor vehicle. Some commercial enterprises are also catering to customers by offering "power-nap solutions":

Caffeine nap
A caffeine nap is a power-nap that was preceded by the intake of a caffeinated beverage such as coffee or an energy drink. A caffeine pill can be used as well.

To be most effective you must take the source of energy quickly and be able to fall asleep within minutes afterwards. Otherwise the energy source will begin to work and will prevent you from falling asleep. With this in mind, the energy pills will get absorbed slower than the energy drink and might be the best choice.

Once asleep the energy source will begin to enter your system and will wake you up in the normal time frame of a power-nap (20-30 minutes). Once woke you will have the energy from the nap and a boost from the energy source as well.