We all have our own cold-avoiding rituals: sipping soup, sucking zinc, mainlining OJ—but it turns out the most powerful way to ward off the rhinovirus costs nothing and is equally available to all: sleep. A new study has found that people who sleep fewer than six hours per night are four times as likely to catch a cold than those who rack up more than seven hours. So far, science has established an associative relationship, not a causative one, meaning it’s not clear whether healthy people are healthy because they sleep more, or getting more sleep increases health. One thing is for certain, though: When it comes to triumphing over cold season, a little extra rest can’t hurt. Have you noticed a connection between the quantity of sleep and your vulnerability to colds or other illnesses? Sound off in the comments.