The long days leading up to the summer solstice can also mean late bedtimes and early waking. With so much daylight, short nights and lack of sleep, many feel “wired but tired.” How to stay energized during the day for all that mountain biking and hiking? Take a nap!
The majority of mammals are polyphasic sleepers, meaning they sleep for many short periods throughout the day. Historically, humans have only recently become monophasic sleepers (sleeping only at night), made possible by the invention of the light bulb in the 1879. Many modern cultures have continued to embrace napping however, including China, Italy and Spain.
The duration of a nap can make a crucial difference in whether one feels groggy or invigorated afterward. An Australian study divided nappers into five groups: no nappers, and those who napped for five, ten, twenty and thirty minutes. Each napper was subjected to three hours of post-nap testing to rate alertness, fatigue, energy and cognition upon waking and thereafter. The study found that the nappers who slept for ten minutes benefited from immediate and dramatic improvement across the board compared to the other groups, and those improvements lasted for 2.5 hours. The 20 minute nappers showed delayed minor improvement with benefits lasting two hours; and the 30 minute nappers were impaired in all measures for 50 minutes, at which point the benefits kicked in, lasting for only 90 minutes.
Another small study out of Georgetown University linked napping with increased right brain activity, the hemisphere that is responsible for creative tasks such as big picture thinking and visualization. This surprised the research team as most of the study’s subjects were right handed; they expected an increase in left brain activity. The potential to emerge from a short afternoon nap physically and mentally renewed may produce positive results for a sleep deprived modern workforce.
References:
https://sleep.org/articles/napping-around-the-world/
Brooks A, Lack L. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative?. Sleep. 2006;29(6):831-40.http://explore.georgetown.edu/news/?ID=66294 http://explore.georgetown.edu/news/?ID=66294