Students might think twice about pulling all-nighters for final exams with the news that sleeping for five hours or less per night could cause weight gain, according to a psychiatry and behavioral sciences professor from Stanford University.
Emmanuel Mignot, who conducted the study in connection with the Wisconsin Sleep Cohort Study, said the study included about 1,500 subjects divided equally by gender. Ages varied from 30-70 years old, and habits included smoking and drinking alcohol.
"It's possible the college student population is more vulnerable to this bad combination of limited sleep and unhealthy food," Mignot said.
According to the 2004 National College Health Assessment, 64 percent of students reported difficulty sleeping. Of that number, 24 percent reported a lack of sleep impacted their school work.
Mignot said the diversity of the subjects' background made it representative of the general population.
But Olin Health Center Health Education Services Coordinator Dennis Martell said a single study cannot be entirely conclusive.
Martell said the study could simply indicate that when people remain awake, they have more time to eat.
Mignot said this is a valid idea and that part of the problem is that food is so readily available to people.
His hypothesis states that years ago people increased their activity when they cut back on sleep, so their body needed more calories to function. As a result, the body created a reaction to a lack of sleep.
When people sleep fewer than five hours per night, the study showed an average increase of 14.9 percent in the hormone ghrelin, which spurs appetite.
"When you don't sleep enough you have more time for eating, you increase your appetite and food is readily available to indulge," he said.
Ronda Bokram, a nutritionist at Olin Health Center, said the increase in food intake is a logical reaction to stimulate blood sugar when students stay up late.
Starchy foods will increase blood sugar, whereas healthier alternatives, such as vegetables, will not, she said.
"Eating late at night or eating if students are not sleeping doesn't necessarily cause a problem, especially if that's part of their daily intake," Bokram said.
The study also showed the levels of the hormone leptin, which tells the brain the body has enough food, decreased by 15.5 percent if sleep was limited to five hours or less.
Martell said a number of factors prevent students from getting enough sleep, which should be 6-8 hours per night.
These include stress from school and jobs, a desire to socialize and adjusting to a new environment.
Setting boundaries of when to sleep is important at college, where there are no parents, Martell said.
"What students want and the body needs are two different things," he said. "The body needs to regain its energy sources, and it does that by refueling with sleep."
