Losing sleep? According to several recent studies, a correlation has been found between being overweight and getting fewer hours of sleep at night.

Two new studies showed that people deprived of sleep had hormonal imbalances. Those who slept less had more of the hormone ghrelin, which produces hunger, and less of the hormone leptin, which produces a feeling of fullness.

They also craved more high-calorie foods than they did with adequate sleep.

One study done at the University of Chicago showed that a group of men in their 20s who only slept four hours a night for two nights had a 24 percent increase in appetite.

Another study done at Stanford University analyzed the sleep patterns of more than 1,000 people. Those who slept less than eight hours a night were heavier than those who got enough sleep.

In November, Columbia University researchers found that people who slept less than four hours a night were 73 percent more likely to be obese than people who had seven to nine hours of sleep. There was a 50 percent risk of obesity for those who slept five hours a night, and a 23 percent risk for those who slept six hours

“Most people think that if you’re sleeping less, that means you would actually lose weight because you have more hours of activity,” said Ruth Litchfield, assistant professor of food science and human nutrition.

However, people usually eat more to compensate for sleep loss, Litchfield said.

“Your brain doesn’t recognize that your body’s full,” said Jessica Steinitz, program manager for the National Sleep Foundation.

According to the National Sleep Foundation, more than 37 percent of young adults sleep less than seven hours a night.

“Eight to nine hours is what they really need,” said Marc Shulman, staff physician for the Thielen Student Health Center. “College students tend to vary their sleep depending on the day.”

Having a sleep routine is important to getting enough sleep every night, Shulman said.

“Good sleep habits would include going to bed at the same time and waking up at the same time every day, even on the weekends,” he said.

For college students, this isn’t always possible. But without enough sleep, weight gain isn’t the only potential problem. Difficulty concentrating, memory problems, irritability and fatigue are other problems associated with sleep loss.

“Since the body does not ‘learn’ to function on less sleep, it is important to clear time for sleep even if your schedule is insanely busy,” Steinitz said. “Any studying or learning that occurs during the day will be retained much better if you get a good night’s sleep afterwards.”

Occasional sleep deprivation isn’t a problem, Litchfield said. The problem occurs when students are frequently functioning on little sleep. This could increase their risk for weight gain, she said.

“It comes back to just trying to maintain a healthy lifestyle on a regular basis,” Litchfield said.