Staying Up All Night

Risk Rating: 2
Whether you’re working on deadline or you just want to finish that page-turner, pulling an all-nighter once in a while may make you feel like a zombie, but it has little affect on your health, says Matthew Ebben, Ph.D., an assistant professor of psychology and neurology at the Center for Sleep Medicine at the Weill/Cornell Medical College, in New York City.

But you won’t be at your sharpest the next day. Since some studies have shown that a person can’t learn as well after a sleepless night, you may want to postpone any important classes or meetings for another day.

And think before you drive. The effect of not sleeping is similar to being drunk, says Ebben. If your eyelids feel heavy before your commute, consider having someone else drive you to work or take public transportation.

Grabbing a catnap may help you regain a little bit of footing, but Ebben cautions that taking naps during the day on a consistent basis can throw off your nighttime sleep patterns.

Sleeping on the Same Sheets More Than a Week

Risk Rating: 1
If you blow off doing the laundry for a few weeks, your sheets might not smell fresh and they’ll be plenty wrinkled, but in most cases they won’t cause you any harm. Your one concern: microscopic dust mites. “These tiny bugs live in all mattresses, bedding, and sheets — no matter how clean you or your bedclothes are,” says Kelly M. Cordoro, a clinical instructor of dermatology at the University of California, San Francisco. Washing your bedding in hot water will kill the tiny pests, but they can accumulate again quickly. If the mite count becomes too high, people with skin sensitivity and allergies can have attacks of eczema, rhinitis, or asthma. If frequent laundry days don’t help, they might want to try hypoallergenic dust covers for their mattresses and pillows.