Susceptibility to Colds Linked to a Lack of Sleep
The New York Times
Published: Jan 14, 2009
People who got less than seven hours of sleep a night were almost three times more likely than those who slept eight hours or more to get sick after exposure to a cold virus, a new study has found.
Adults who spent a lot of time in bed tossing and turning were even more vulnerable, the researchers reported.
“The poorer your sleep, the worse off you are,” said Sheldon Cohen, a professor of psychology at Carnegie Mellon University in Pittsburgh and first author of the study, which was published on Monday in The Archives of Internal Medicine. “That was the surprise.”
Dr. Cohen and his colleagues followed 153 healthy men and women ages 21 to 55 for two weeks, asking each day how they had slept the night before and assessing their sleep efficiency, the amount of time a person actually slumbers between going to bed and rising the next morning.
Then researchers quarantined the participants in one floor of a hotel and exposed them to a rhinovirus, the infectious agent responsible for most common colds, by dropping a controlled amount of viral particles in their noses, Dr. Cohen said.
The vast majority of the participants, 88.2 percent, became infected, meaning the virus started replicating in their nasal passages. But only 35 percent went on to develop a full-fledged cold, including symptoms like congestion, the scientists found.
Participants who slept less before exposure to the virus were more susceptible to developing a cold than those who got more sleep. But low sleep efficiency was even more strongly associated with developing a full-fledged cold, the researchers found.
People who were awake 8 percent or more of the time they were in bed were 5.5 times more likely to develop a cold than those who laid awake only 2 percent of the time or less, researchers said.
Sleep disturbances may influence the regulation of pro-inflammatory cytokines and histamines, which are released in response to infection and play a role in inflammation and allergic reactions, said the researchers.
Diana Lauderdale, author of a recent study that found people who don’t get much sleep are more likely to develop calcium deposits in their coronary arteries, a risk factor for heart disease, said the new study indicates that quality of sleep may be at least as important to health as quantity of sleep.
Unfortunately, she said, people don’t have much control over their sleep efficiency.
“It’s consistent with anecdotal impressions many people have that when they get a bad night’s sleep, when they worked as students through the night or had small children that hadn’t slept at night, that 36 hours later, they have a cold,” said Dr. Lauderdale, an associate professor of health studies at the University of Chicago Medical Center.
“There is a lot that is not yet understood about sleep and the inflammatory response," she added. "Lots of pieces of evidence are pointing to there being something there.”
© The New York Times. All rights reserved. This article originally appeared in The New York Times.
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