Microbiologist Reveals How Often You Should Wash Your Bedding to Combat Bacteria and Mites

A microbiologist has highlighted the crucial importance of regular bedding washing to keep bacteria, fungi, and allergens at bay. Primrose Freestone, senior lecturer in clinical microbiology at the University of Leicester, explains that each night we shed hundreds of thousands of skin cells and secrete oils and sweat—even if we’ve showered beforehand—creating an ideal environment for microbes in our beds.

“Our skin hosts millions of bacteria and fungi, which transfer onto sheets, pillows, and duvets during sleep,” Freestone explains. “While fresh sweat is often odorless, bacteria like staphylococci break it down into unpleasant smells, which is why you might wake up with body odor despite going to bed clean.”

Additionally, outdoor pollutants like dust, pollen, and allergens latch onto our hair and skin before we even get into bed, contributing to poor bedroom air quality and potentially triggering allergies and breathing issues. The shed skin also nourishes microscopic dust mites that thrive in the warm, moist environment of bedding and mattresses.

“Though dust mites themselves aren’t harmful, their fecal droppings are powerful allergens that can worsen eczema, asthma, and allergic rhinitis,” Freestone warns. Fungi such as Aspergillus fumigatus have also been found in used pillows and can cause severe lung infections, especially for individuals with weakened immune systems.

Freestone offers specific recommendations for washing your bedding regularly:

Sheets and pillowcases: Wash weekly to remove sweat, skin cells, and bacteria.
Mattress covers: Clean every one to two months to minimize mite and allergen build-up.
Pillow interiors: Wash or replace every six months due to dust mite accumulation.
Blankets and duvet covers: Wash every one to two weeks depending on usage.
Duvets: Clean every six months to maintain freshness and hygiene.

“Your bed might look clean, but it’s a hotspot for microbes, allergens, and irritants that accumulate rapidly,” she notes. “Frequent washing isn’t only about freshness—it’s essential for health. Removing sweat, skin, dust, and microbes reduces allergic reactions, prevents infections, and controls odors. Since quality sleep impacts heart health and mental clarity, maintaining a hygienic sleep environment is a small investment with big benefits for your wellbeing.”