You're washing your bedding wrong! Microbiologist reveals how often you should really clean your sheets - and the item you should refresh every three days

With our hectic daily lifestyles, cleaning the bed linen is surely one of the household chores that gets put off the most. 

And with the mammoth effort involved in putting on a double duvet cover, it's little surprise some of us go for months before getting around to it. 

But if you rarely change your bedding, you may want to start making it one of your regular jobs, according to a microbiologist. 

Dr Primrose Freestone, professor of clinical microbiology at the University of Leicester, says we should wash our sheets and pillowcases one a week at least. 

However, for those who sweat heavily, have been ill, or share their bed with pets, the sheets should be washed even more often. 

Washing linen removes body sweat, oils, microbes, allergens and dead skin cells, which can lead to infections and allergic reactions - not to mention other unsavoury stains. 

'While we often focus on how many hours we’re getting, the quality of our sleep environment matters too,' said Professor Freestone. 

'Regular laundering removes the biological soup of sweat, skin, dust and microbes, which helps to reduce allergic reactions, prevent infections and keep odours at bay.'

Each night, we shed thousands of skin cells, excrete oils from our sebaceous glands, and sweat up to half a pint of fluid – even if we’ve showered just before bed. 

Skin sweat and oils can support the growth of microorganisms, too small to be seen by the naked eye, Professor Freestone explains in a new piece for The Conversation. 

Our skin hosts millions of these microbes such as bacteria and fungi, many of which are transferred onto sheets, pillows and duvets as we move during the night.

Unfortunately, a gradual build-up of bacteria on your sheets can increase the likelihood of acne, eczema, itching and asthma. 

Fresh sweat emitted from our skin may be odourless, but bacteria on our skin break it down into smelly byproducts – which is why we get BO. 

So we should be washing sheets and pillowcases once per week at 140°F/60°C or higher with detergent to kill the bacteria, the academic said. 

Meanwhile, some fungus species, such as aspergillus fumigatus, have been detected in used bed pillows and can cause serious lung infections, particularly in people with weakened immune systems. 

Another fungal species called Candida albicans – which can cause oral thrush, urinary tract infections and genital yeast infections – can survive on fabrics for up to a month. 

What's more, flakes of skin we shed every night become food for dust mites – microscopic, insect-like creatures that thrive in warm, damp bedding and mattresses.

The mites themselves aren’t dangerous, but their faecal droppings are potent allergens that can aggravate eczema, asthma and allergic rhinitis, also known as hay fever. 

Also, during the day, our hair and bodies collect dust and pollen, which can also transfer to our bedding – triggering allergies and affecting breathing. 

However, if you sleep with a pet, you should launder your bed sheets and pillowcases even more often – every three to four days, according to the expert. 

'Animals introduce extra hair, dander, dirt and sometimes faecal traces into your sheets and blankets, increasing the frequency at which you should be washing them,' she said. 

According to Professor Freestone, it's not just sheets and pillowcases that should be cleaned more often. 

Mattresses should be stripped and vacuumed weekly, duvets should be laundered every three to four months, and pillows themselves should be washed and dried every four to six months. 

Pillows should also be frozen in a suitable freezer for at least eight hours to kill the dust mites lurking inside them. 

According to research, some Brits go months without washing their bedding, even though freshly-laundered sheets have been linked with a better night's sleep.  

A 2022 YouGov poll found that just 28 per cent of Brits wash their bed sheets once a week, while 4 per cent wait for two months or more. 

Potential factors for delaying the job include laziness, lack of time, finding it physically difficult and prioritizing use of the washing machine to clean clothes instead.   

According to Professor Freestone, regular washing is 'more than just a question of cleanliness' as a good night's sleep is 'essential for normal brain function and overall health'. 

'A clean, welcoming bed with crisp sheets, soft pillowcases and fresh blankets not only feels good, it also supports better rest,' she added.  

'A hygienic sleep environment is a small but powerful investment in your wellbeing.'