INDIANAPOLIS, Ind. (Feb. 9, 2016) -- If you've always wondered about claims that your mattress doubles in weight and should be replaced "every eight," CBS4 went to work to see what's really happening the longer you keep your mattress.
We've all heard countless times that we spend a third of our life sleeping, so it's no stretch to think about what happens during all of that time on your bed.
Commercials will tell you about germs, dead skin cells, dust mites, and other gross bed-mates. Some even say you should replace your mattress after eight years.
In order to test that theory, we went to the experts and did some work of our own. We set out to swab mattresses, new and old, then compare the test results to see what's hanging out.
First, CBS4's Jill Glavan talked to Lauren Taylor, the third-generation owner of local company Holder Mattress.
"Some kids went to daycare, I went to a mattress shop," Taylor said.
She hears all the time from customers about the replace-every-eight theory.
"We hear it every day. ... People will ask, 'I’ve had mine X number of years, should I replace it?'" Taylor said.
Taylor let us use a brand new mattress, straight out of the bag. We swabbed it as a control, to test the other mattresses against it.
Who better to offer up their mattresses for testing than reporter Jill Glavan's co-workers, and her own family?
First, we tested a mattress that has been in the Glavan family since the 1930's, used mostly as a kids' bed.
"My dad actually used this mattress originally, he was born in 1925," mattress test subject Bob Glavan said. "I'm not sure what to expect. I'm hoping you don't find anything."
Next up, Meghann Miller, a newlywed with a familiar problem: her husband Chris' mattress, which has been laying out, uncovered, while the two try to get rid of it.
"(It's) at least 10 years old, maybe more. Who knows?" Miller said.
Finally, the newest mattress we tested belonged to Allison Herman, who bought it six years ago. In the meantime, though, her cat was sick and went to the bathroom on the bed multiple times.
Herman said she cleaned the mattress, and that it is still comfortable, but she was worried about what her pet might have contributed.
"I’m a little bit afraid of how the mattress is going to come out on the test, to be honest," Herman said.
With all of the samples ready, we packaged them up and took them to HML, Inc. in Muncie, where they tested the swabs.
Director of Microbiology Jaima Ballentine laid out the results, which even shocked her in some ways.
The most surprising: Glavan's 80-year-old mattress was the cleanest of them all, coming closest to the control mattress with just a minimal amount of bacteria. It is likely due to the mattress pad protecting the mattress over that amount of time.
"That tells me then ... that (it's) going to put a protective layer," Ballentine said.
It was a similar result in the case of Herman's mattress, which showed low amounts of bacteria, but she had a little extra lurking there. Hers was the only mattress to test positive for staphylococcus, the bacteria that leads to staph infection.
"Chances are she's probably a carrier for it," Ballentine said.
Ballentine said about a third of people carry that bacteria, so it shouldn't be a problem, but it can lead to illness or infection.
Finally, the dirtiest mattress was the Millers', with some major bacteria hanging out. Ballentine found more than 2,000 bacteria colonies, most likely because the mattress was sitting out with no cover.
In order to reach conclusions about our test results, we talked to Indiana University Professor Dr. Marc Lame, an entomologist. Though our test could not pick dust mites or skin cells, Lame said there is no proof that they are weighing down your mattress at all.
"I have not found any credible research that shows that," Lame said.
He said dust mites could be a problem if you have allergies, but vacuuming regularly, using a de-humidifier, and getting an allergen-specific cover should get rid of them. Plus he said the mites live among us, anyways.
"I know it’s kind of yucky but the fact is that this is part of our environment," Lame said.
If it's any consolation, Lame himself didn't see any issue with keeping a mattress for a long period of time.
"I bought my current mattress probably 25 years ago, so I’m a big believer in keeping mattresses around," Lame said.
Taylor told us the same, saying she did not advise anyone to get rid of a mattress because they worry about skin cells or dust mites. Instead, she suggested that it is whether you are sleeping well that should advise your choice.
"There is no magic number. You can re-evaluate at (eight years) if that works for you, but at the end of the day it’s whether or not that mattress is still comfortable and still does what you need it to do," Taylor said.
We also talked to Mary Helen Rogers, VP of Marketing and Communications for the Better Sleep Council. The council is part of a trade association that represents sleep products around the country and educates consumers about the "direct relationship between sleep and health."
You can see Rogers' expert take on your mattress in this bonus video below: