Are You Getting Enough Sleep to Fend Off the Common Cold?

Cold season is officially here and for the next several months many people will be loading up on vitamin C in hopes of keeping the common, but physically draining, illness at bay. However, gorging on oranges is not necessarily the answer to making it through without the sniffles — but extra sleep might be.

Researchers found a strong correlation between sleep duration and the likelihood of developing a cold. The equation seems fairly simple — less sleep means a higher risk of developing a cold. But how many hours is enough?

“In our busy culture, there’s still a fair amount of pride about not having to sleep and getting a lot of work done,” lead author Aric Prather, PhD, of the University of California, San Francisco, said in a news release.

To find out the specifics on a healthy night’s sleep, the team assessed 164 men and women ages 18 to 55. This is not the first study to look at the relationship between sleep and the common cold; however, previous research came to conclusions based solely off of participants’ sleep diaries, which could be bias. In addition to patient reporting, this new analysis also included data from wrist actigraphy to detect sleep duration and continuity. The observation period lasted for seven consecutive days followed by administration of nasal drops containing the rhinovirus. The patients were then monitored for five days.

According to the results published in SLEEP, shorter sleep duration increased the likelihood of catching the clinical cold. Compared to the subjects who had more than seven hours of sleep, those who slept less than five hours were 4.5 times more likely to become sick and those who rested between five and six hours had a 4.2 times greater chance. The authors noted that subjects who slept between six and seven did not have a greater risk. Multiple other factors were considered, however, they did not demonstrate to have relevance to developing a cold like sleep did.

“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,” Prather confirmed. “With all those things taken into account, statistically sleep still carried the day and was an overwhelmingly strong predictor for susceptibility to the cold virus.”

The findings add to the growing evidence that sleep affects your physical health beyond the scope of what an extra cup of coffee can do.