Lack of sleep can lead to the common cold

By Nadia Kounang, CNN

A new study published in this week's journal SLEEP, finds that people who sleep less than six hours are more likely to catch a cold. Researchers tracked 164 healthy men and women for a week at a time, monitoring how much they slept and exposing them to the rhinovirus, also known as, the common cold.

Sleep at least six hours a night

Aric Prather, lead author of the study, and his colleagues found that those who slept less than five hours were 4.5 times more likely to have a cold than those who slept seven hours.

Only 18% of those who slept six or more hours got a cold, while 39% of those slept less than six hours got the virus.

According to the Centers for Disease Control and Prevention, most adults average two to three colds a year and kids have even more.

Prather pointed out that when we don't sleep enough, it may impact our immune systems in a variety of ways -- from how the cells act to enabling our inflammation pathways.

"We don't know conclusively what happens, but there are a variety of pathways and they all work together and ultimately put people at risk," Prather said.

Related: Do you have allergies or just a cold?

Shalini Paruthi, director of the Pediatric Sleep and Research Center at Saint Louis University, put it simply: "It looks like an adequate amount of sleep allows our body to mount a better immune response."

Americans sleep less and less

We spend a third of our lives asleep -- that's about 25 years. But, sleeping is becoming a challenge in the United States. Americans are simply sleeping less and less. In 1985, the average amount of sleep was close to 7.5 hours, and according to the American Academy of Sleep Medicine has dropped to 7.18.

Aside from catching more colds, lack of sleep has also been associated with mental alertness and driving ability, as well as increased risk of heart attack, stroke, diabetes and obesity.

"I think this study provides further evidence the important for adequate sleep," Nathan Watson, president of the American Academy of Sleep Medicine said. "People need to consider sleep an important tool to healthy life, as opposed as an impediment to staying awake."

Before you turn off your alarm off -- keep in mind that there have been studies that have found that those who sleep nine or more hours could increase their risk of death. But, according to James Gangwisch, a sleep researcher at Columbia University, said those studies didn't explore whether those people had underlying illnesses.

How to sleep better

So what can you do to get a better night's sleep? In addition to setting an alarm in the morning, try setting one at night to remind you that it's bedtime. Keep your bedroom as dark as possible. And when you wake in the morning, get out and get some sun. The light wakes up your brain and tells it to be alert, and later on, that helps you ease into sleeping better at night.

Prather said we need to raise the profile of sleep.

"Sleep usually takes a back seat to everything else we're doing, and it's a disservice," Prather said. "There's a real health cost to doing that."