Tired Man (IStockphoto 6832296)

The presidencies of Barack Obama and George W. Bush are as different as night and day. President George W. Bush, who famously liked to retire shortly after 9 PM, started his last day in office the way he started most of the preceding days— at his desk before 7 am. President Obama brings late nights and long hours to the White House. The apparent night owl holds conferences with senior staff through 11 PM and urges employees to return to work after dinner.

Scientists agree that a combination of genetics and lifestyle determines whether someone is a morning or night person. The 9-to-5 schedule favors the early riser, whose sleep patterns mesh naturally with the rising and setting sun. Then there are the night people, who fight alarm clocks and only encounter sunrises at the movies. Is one type more likely than the other?

More people consider themselves early birds than night owls. According to the National Sleep Foundation's 2005 Sleep in America™ poll, the odds that an adult is “a morning person” are 1 in 1.82 (55%). And there are definite perks to being an early riser. One small study from the University of Alberta concluded that a morning person's strengths peak at 9 AM and remain constant throughout the day—ideal for a desk job.

The odds that an adult is “a night person” are 1 in 2.44 (41%). They may be less common, but a small study published in April, 2009 in the journal Science found night-owls had more mental stamina than early-risers, besting them on tests of alertness after more than ten hours of being awake. If those results hold true for the general population, it’s good news for students who have enrolled in two new classes being offered at Boston’s Bunker Hill Community College, “College Writing” and “Principles of Psychology.” Both start at a quarter to midnight and end at 2:30 in the morning.

Those students probably remember with horror the high school chemistry class that started shortly after the sun came up. Others can’t imagine being awake after midnight, much less learning the ins and outs of the human psyche. You are likely to do your best work, and enjoy your pursuits more, if your daily schedule doesn’t fight what your body wants to do. Perhaps the “better” sleep/wake cycle is simply the one you naturally prefer.

All living entities come installed with an internal clock that controls our circadian rhythms—essential biological processes, like body temperature and sleep—which operate on a 24-hour cycle. Our clock is found primarily in an area of the brain called the superchiasmatic nucleus. This clump of cells, part of the hypothalamus, uses environmental cues, like the amount of sunlight present, to control the body’s production of melatonin, a hormone that makes you drowsy.

Humans are constantly testing their biological clock. Night employees work double shifts to provide for their families. Students pull all-nighters to cram for tests. And let’s not forget about jet lag and daylight saving time. Most people can handle these changes, but those whose genetics push them toward being more of a morning or night person can’t cope with irregular sleep schedules. For example, scientists have found that those with certain copies of PER3 genes showed far more signs of drowsiness when kept awake for long periods of time. The opposite are those with Afh, the “after-hours” gene, a genetic variant of Fbxl3. Studies with mice show promise that possessing the altered gene may extend the animals’ body clocks from a 24 to a 27-hour day. Probably a good gene for a world leader to have, but for now, even President Obama needs his rest.