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Less than 6 hours sleep makes people four times more likely to catch cold

People who sleep six hours a night or less are four times more likely to catch a cold when exposed to the virus, compared to those who spend more than seven hours a night sleeping, a new study suggests.

The study, led by UC San Francisco and including Carnegie Mellon University, found that people who had slept less than six hours a night the week before were 4.2 times more likely to catch the cold compared to those who got more than seven hours of sleep. Those who slept less than five hours were 4.5 times more likely.

Sleep was more important than any other factor in predicting subjects' likelihood of catching a cold, including stress, age and race, Aric Prather, PhD, assistant professor of psychiatry at UCSF and lead author of the study said.

"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," he said.

The study used 164 volunteers who underwent two months of health screenings, interviews and questionnaires to establish their stress, temperament, and alcohol and cigarette use.

The researchers also measured participants' normal sleep habits a week before administering the cold virus. They then administered the cold virus via nasal drops and monitored them for a week, collecting daily mucus samples to see if the virus had taken hold.

Prather added: "In our busy culture, there's still a fair amount of pride about not having to sleep and getting a lot of work done. We need more studies like this to begin to drive home that sleep is a critical piece to our wellbeing."