We spend around a third of our lives in bed, and at the end of a long day, the last thing we want to think about is what may be hiding in our bedsheets. On average, fewer than half of all Americans wash their sheets once or twice a month, resulting in an accumulation of sweat, skin cells, and dust that allow for bacteria and mold to thrive, providing a less than restful experience. This makes the washing of sheets essential, so let’s take a closer look at how often bedspreads should be changed.
Throughout the day, hairs collect a buildup of oils and dirt, which are transferred to our pillowcases when we sleep. It was found that the average pillowcase gains nearly 3 million bacterial colony forming units (CFU) per square inch for every week it is not washed, which is almost 10 times more bacteria than a standard pet food bowl. This includes gram-negative and gram-positive rods which can cause skin infections. This accumulation of dirt and oils can also contribute to skin blemishes including blackheads and acne.
Like pillowcases, after one week of use, bedsheets soon become home to 5 million CFU, which is 238x more than the average kitchen sink.
In addition to bacteria, bedsheets are often covered in dead skin cells. The average adult sheds 500 million skin cells each day, which are then consumed by dust mites. The longer we go without washing our sheets, the more time these mites have to grow, multiply and produce waste which many people are . Dust mite allergies may cause symptoms similar to seasonal allergies, including sneezing, runny nose, itchy eyes, and congestion, while more serious allergies can result in respiratory issues including asthma.
Mattresses are also home to millions of bacteria. Mattresses that are one year old were found to have 3 million CFU, the same as a one-week-old pillowcase, while a seven-year-old mattresses has a wider variety of bacteria and over 16 million CFU. Thankfully, since mattresses are touched less frequently than pillows and sheets, they accumulate microbes much more slowly. Mattresses can be very difficult to clean, so frequent washing of sheets and the use of mattress protectors may slow this process down further.