But what's inside your bed may be making you sick, not safe.
There's a multitude of contaminants -- bacteria, fungi and allergens -- that you can't see but studies show are there. When you move around as you sleep, you kick them up until the air and breathe them in.
Here's what's lurking in your bed.
Four out of five homes in the United States have at least one bed with dust mites, according to the American Lung Association. Believe it or not, the pests themselves aren't the big problem. It's their feces.
"Dust mite droppings are highly allergenic," said Dr. William Berger, a fellow with the American Academy of Allergy, Asthma & Immunology.
Even if you aren't allergic to dust mite feces -- and only an allergy test can tell you for sure -- they might still irritate you, the way pepper would if it blows into your nose and eyes.
The American Lung Association has several recommends for limiting dust mites
, including getting rid of carpets and damp mopping your floors.
Mold and fungi
Brendan Boor, an assistant professor of civil engineering at the Purdue University College of Engineering, studies beds for a living. He said research shows that beds have mold, fungi and bacteria, contaminants smaller than the diameter of your hair.
The fungus facts alone will make you shudder. One study
looked at 10 pillows in regular use and found that they collectively had 47 species of fungi.
Solution: Boor recommends placing an air purifier with a HEPA filter next to your bed.
Gallons of sweat
Think about it: You spend a third of your life in bed, so you're going to sweat there -- up to 26 gallons a year, according to some studies.
"You can have strep or staph on your skin, and that could infect you or your partner," Berger said.
Solution: The American Lung Association recommends that you wash your bedding in hot water at least once a week.
Your pet's bodily waste
No matter how much you love your pet, you might be allergic to their dander, urine and saliva.
Solution: If you have a pet, Boor recommends vacuuming your mattress and pillows at least once a week. Even if you don't have one, he says, vacuuming is useful to get rid of other contaminants.