Sleep: protective shield against colds

Dr. Andrea Bannert has been with since 2013. The doctor of biology and medicine editor initially carried out research in microbiology and is the team's expert on the tiny things: bacteria, viruses, molecules and genes. She also works as a freelancer for Bayerischer Rundfunk and various science magazines and writes fantasy novels and children's stories.

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As soon as the temperatures fall, many struggle with coughs, runny nose and Co. There is a simple trick that anyone can use to outsmart the cold viruses.

Lack of sleep weakens the immune system - this has been known for a long time. Now Aric Prather and colleagues from the University of California have examined this phenomenon in more detail using the example of the common cold. To do this, they looked for 164 test subjects and kept a close eye on their sleep duration from a week before the start of the experiment. A sensor that resembled a wristwatch helped the researchers. In a questionnaire, the test subjects also provided information about their stress level as well as alcohol and cigarette consumption. The researchers then took these immune system killers into account in the statistical analysis of the data.

After a week of surveillance in this way, the participants entered the laboratory and deliberately exposed themselves to rhinoviruses in the name of research. These typical causes of colds were applied directly to the test subjects' nasal mucosa with the help of nasal drops.

Four times as likely to catch a cold

From there, the viruses invade the body, multiply and trigger the familiar cold symptoms. At least if the immune system fails to fight them off in time. And in fact the ability to put a stop to the pests was very different among the test subjects.

Most often, the viruses successfully made their way through those who had slept an average of less than five hours in the previous week. These short sleepers succumbed to a cold 4.5 times more often than subjects who had allowed themselves more than seven hours of sleep. Sleeping for less than six hours is not enough for the immune system: Anyone who slept between five and six hours still got a sniff 4.2 times more often.

Of all the factors considered in the study, getting enough sleep was by far the best shield against the common cold virus. "Regardless of how old people were, whether they smoked or had a lot of stress, a lack of sleep remains the main driver of susceptibility to colds," says Prather, head of the study.

Sleep as the key to health

Sleep is a cornerstone of public health - just like diet and exercise, the scientists write. But in our society, the night's rest is often of little importance. “Many people are proud that they work a lot and sleep little,” says Prather. "We need more studies like this one that show that sleep is a key factor in wellbeing."

Source: University of California San Francisco: Short Sleepers Are Four Times More Likely to Catch a Cold, Aug 31, 2015.

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