Sleep and the Common Cold
Intuition suggests that you're more likely to succumb to a cold if you're tired. But direct evidence of a relationship between cold-catching and sleep has been elusive. A new study published in the January 12 issue of the Archives of Internal Medicine helps to pin down that link.
Researchers led by Sheldon Cohen at Carnegie Mellon University in Pittsburgh tracked the self-reported sleep experiences of 153 healthy men and women ages 21 to 55 (the average age was 37) for 14 days. They then gave each participant a snort of nasal drops containing a cold-causing rhinovirus. For five days after the nose-drops were administered, participants were quarantined and checked for cold symptoms, and their nasal mucus was tested for the presence of the virus. Later, their blood was tested for antibodies their immune systems might have developed to fight that specific viral infection. (I'll spare you the sticky details about weighing used tissues to measure nasal discharge.)
Though 88 percent of the participants were found to have been infected, not everyone actually developed a cold. Those who slept, on average, less than 7 hours per night were nearly 3 times more likely to develop a cold than those who slept 8 or more hours nightly. When researchers looked at "sleep efficiency" -- the ratio of time spent in bed to time actually sleeping -- an even more striking pattern emerged: Those with less than 92 percent efficiency were 5.5 times more likely to develop a cold than those with 98 percent efficiency or better. (Hard to imagine a sleep efficiency better than 98 percent!)
The research team controlled for other variables that could have confounded the study's findings, such as smoking, alcohol consumption, perceived stress level, and psychological factors that earlier research has linked to colds. As to a potential explanation for the apparent link, the study suggests that interrupted sleep -- as hinted at by those low sleep efficiencies -- might monkey with the release of histamines and other substances the body uses to mediate symptoms when responding to infection.
Researchers found no association between feeling well rested -- or the opposite -- and cold susceptibility. But the other findings certainly support the notion that getting enough sleep, particularly during cold season, boosts our resistance.
What about you? Do you find you get sick more easily when you don't get enough sleep?
Posted by: chowx417 | January 13, 2009 6:07 PM | Report abuse
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