28-hour day

The 28-hour day is a concept of time management used by a limited number of students and other people with jobs that allow very flexible work hours. It derives from two principles:
# A sleep period of eight to nine hours is enough to fully recover from more than 16 hours awake for most healthy people.
# The number of hours per week (168) is evenly divisible into six 28-hour days.

People living by the 28-hour day stay awake for 19 to 20 hours and then sleep eight to nine hours, depending on need. The effect is a six day week. [cite web |url= http://www.dbeat.com/28/benefit2.htm |title= 28 Hour Day |accessdate= 2008-02-19 |author= Digital Beat Productions |year= 1997 |format= |work= |publisher= |quote= ] [cite web |url= http://xkcd.com/320/ |title= 28-Hour Day |accessdate= 2008-09-01 |author= |date= |year= |month= |format= |work= A webcomic of romance, sarcasm, math, and language |publisher= xkcd.com |pages= |doi= |quote= ] This time plan requires staying awake in the dark (implying the availability of artificial light) and sleeping during daylight, which may have negative impact on one's personal chronobiology. Most regular schedules and opening hours do not match this weekly cycle, so special arrangements and compromises may have to be made.

Early research into circadian rhythms suggested that most people preferred a day closer to 25 hours when isolated from external stimuli like daylight and timekeeping. Researchers allowed subjects to keep electric lighting on in the evening, as it was thought at that time that a couple of 60W bulbs would not have a re-setting effect on the circadian rhythms of humans. More recent research has shown that adults have a built-in day which averages just over 24 hours, that indoor lighting does affect circadian rhythms, and that most healthy, normal people cannot reset their clocks to 28 hours. [cite web |url= http://www.hno.harvard.edu/gazette/1999/07.15/bioclock24.html |title= Human Biological Clock Set Back an Hour |accessdate= 2008-02-19 |author= |last= Cromie |first= William J. |date= 1999-07-15 |format= |work= |publisher= The Harvard University Gazette |quote= ]

See also

* Shift work

References