The CDC have previously referred to insufficient sleep as a "public health epidemic."
The team reports that people who only get 6 hours sleep a night or less are four times more likely to catch a cold after exposure to the virus than people that get 7 or more hours sleep a night.
"Short sleep was more important than any other factor in predicting subjects' likelihood of catching cold," says lead author Aric Prather, assistant professor of Psychiatry at the University of California-San Francisco (UCSF).
"It didn't matter how old people were, their stress levels, their race, education or income. It didn't matter if they were a smoker. With all those things taken into account, statistically sleep still carried the day."
The Centers for Disease Control and Prevention (CDC) have previously referred to insufficient sleep as a "public health epidemic," linking it with motor vehicle crashes, industrial disasters and occupational errors.
Unfortunately, insufficient sleep is prevalent in the US. According to the National Sleep Foundation, 1 in 5 Americans obtain less than 6 hours sleep on an average work night.
While Dr. Prather had previously found that people who get insufficient sleep are less protected from illness after vaccination than people who get adequate sleep, the aim of his team's new study was to learn how sleep affects how the body responds to real infection.
Less than 5 hours sleep, 4.5 times the risk of catching a cold
A total of 164 participants were recruited and given the common cold virus via nasal drops so that the researchers could analyze how various factors affected the body's capacity to fight the virus off. The participants were monitored for a week and had mucus samples taken each day so the progress of the virus could be assessed.
Prior to being given the virus, each participant underwent 2 months of health screening. Their normal sleep habits were also recorded during the week leading up to the administering of the virus, using a watch-like sensor that was worn overnight.
The researchers found that the participants who had slept less than 6 hours a night during the preceding week were 4.2 times more likely to catch a cold than participants who managed to get 7 hours or more a night. Participants who slept less than 5 hours were 4.5 times more likely.
One of the strengths of the study, according to the authors, is that it is based on the participant's usual sleep cycles rather than artificially depriving the volunteers of sleep. "This could be a typical week for someone during cold season," Dr. Prather states.
While the study provides further evidence for the importance of sleep in keeping physically healthy, the researchers believe it will take a lot more work before widespread attitudes toward sleep are changed.
"In our busy culture, there's still a fair amount of pride about not having to sleep and getting a lot of work done," Dr. Prather concludes. "We need more studies like this to begin to drive home that sleep is a critical piece to our wellbeing."
Recently, MNT reported on new research revealing the mechanism behind how an animal's biological clock wakes it up and puts it to sleep. The study's findings could eventually lead to new drug targets for treating disorders related to body clock problems, such as jet lag.