That all-nighter may cost you your health

Staying up late to finish that term paper may cause more than just a need for coffee the next morning.

According to a study released by Carnegie Mellon University, people who sleep fewer than seven hours per night are almost three times more susceptible to the common cold than people who get adequate rest.

Led by Carnegie Mellon psychology professor Sheldon Cohen and published in the Archives of Internal Medicine earlier this month, the study closely followed 153 volunteers, including 78 men and 75 women, ranging from 18 to 55 years old.

"There has been quite a bit of research showing that people who lose sleep show suppression of immune system," Cohen said in an interview posted on the Carnegie Mellon Web site. "We thought, given that the immune system is the central physiological system in responding to virus, that people who didn't sleep as well may be more susceptible to cold when they are exposed to virus."

Participants reported their sleep duration and sleep efficiency for 14 days.

They were "quarantined, administered nasal drops containing a rhinovirus and monitored for the development of a clinical cold . on the day before and for 5 days after exposure," according to the study.

Quality of sleep is also crucial for lessening susceptibility to colds.

In order to measure the quality of sleep, the study used a method called "sleep efficiency," which measures how much one's sleep was disturbed.

The study said that participants with less than 92-percent efficiency were five times more vulnerable to a cold than those with 98-percent or more efficiency. Other factors such as demographics, body mass or health practices cannot explain these relationships.

Penn has not yet identified whether students are similarly affected by sleep deprivation, however.

"Typically, there is an increase in flu and cold in winter," said Evelyn Wiener, the director of Student Health Services. "However, it is impossible to know whether lack of sleep increases illness at Penn."

Still, she suggests students get adequate rest, eat well and wash their hands.

Wharton sophomore Dillon Forrest agreed.

"Little decisions such as washing hands and eat fruits can also go a long way to preserving for health," he said. "Sleep is good."

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