The student who hates mornings, who won't sign up for an 8 a.m. class, may well be forging a career path and forecasting long-term job performance.
A new study distributed by the American Academy of Sleep Medicine injects a new consideration into the theory that people's internal body clocks influence their "morningness" or "eveningness."
The study authored by Frederick Brown, an associate professor of psychology at Pennsylvania State University, suggests that this "lark" versus "owl" tendency — whether caused by nature or nurture — appears to influence students' choices of college majors.
And that could have long-range job consequences. For instance, if a night owl avoids early-morning classes, and all pre-med chemistry prerequisites are taught at 8 a.m., it's unlikely that student will choose to become a doctor.
Brown had a group of students complete evaluations to rank their "morningness" or "eveningness" tendencies. It then looked at their major fields of study.
"They end up with a declared major that depends on what they're interested in, what they're good at, what they might have fun with, and what they might want to do for the rest of their lives," Brown said in a phone interview. "But they also pay attention to when they'll have to work."
Brown found, for example, that students with high "eveningness" scores, gravitate to such majors as the performance arts, media or information systems, where work hours skew later in the day or even overnight.
A student's "morningness-eveningness influence" involves personality traits and a built-in biological tolerance for early or late or irregular job hours, he said.
The connection between college majors and body clocks needs further investigation with larger samples, and that is beginning, Brown said.
"Some people are what we call 'invulnerables,' " Brown said. "They get by on short sleep or disruptions for long periods. But one of our conclusions is that a mismatch of genetics and job characteristics is important.
"The genetic component is well-established," he said. "About half the population are daytime people, about one-quarter are moderate to extreme morning types, and about one-quarter are moderate to extreme evening types."
Knowing one's own type is important for workers who want to maximize job performance, productivity and personal health. There's also a safety issue. Sleepy workers can't be as aware as they might need to be.
"It's bad for your health and for employee engagement to have night or shift work if you're not set up for it," said Leigh Branham, a consultant with Keeping the People Inc. in Overland Park, Kan. "It's a vicious cycle when sleep problems and stress interfere with job performance."
In the sleep lab at the University of Kansas Hospital, medical director Damien Stevens said the medical community continually debates the "lark" versus "owl" theories about how much of a person's sleep preference is organic and how much is volitional — behavior developed by choice.
What is scientifically known is that an area of the brain, the suprachiasmatic nucleus, sends signals that keep mammals on a 24-hour schedule, influenced mainly by light. But individuals' 24-hour schedules — their circadian rhythms — aren't exact, and they often change with age.
"The problem with sleep research is that it's difficult to sort out what's endogenous (regulated by the internal body clock) and what's exogenous (external input)," Stevens said.
But, he said, researchers do believe that individuals can adjust their body clocks if they're consistent about changing sleep and wake times. That's why changing shifts — alternating between day and night work hours — is a problem. There's no chance for consistency.
Nancy Spangler, a consultant with Partnership for Workplace Mental Health, said failure to get the consistent sleep that an individual needs can lead to more than physical fatigue. It can lead to stress and depression.
"This can be a difficult problem in people who have chronic shift work, such as nurses, who alternate day and night shifts," Spangler said. "It's far better to have a shift and keep it. Fortunately, more employers are aware of that."