Dr Karl: This is how often you need to wash your sheets and exactly why your bedding is dirty

Popular Aussie scientist Dr Karl Kruszelnicki has lifted the lid on how often you need to wash your sheets – and why they get so disgustingly dirty in the first place.

In a TikTok video, the 76-year-old explained that on average, you should be washing your bed sheets every two weeks, but you might need to be doing it more often if you live in a hot place or sweat often during the day.

‘Why do you have to change your sheets? Well, every day you generate from your skin about one and a half grams of skin cells, which both attract and are enough food for a million dust mites,’ Dr Karl said in the clip.

‘And then on the other hand, while you’re lying in bed you might have a little fart,’ he said.

This all contributes to people needing to wash their sheets much more often than they might think.

When it comes to how often, the scientist said if you’re in a ‘very sweaty environment and you sweat during the day and came home all sweaty and didn’t shower before bed or wear pajamas’, you would need to be washing them twice a week.

Meanwhile, in a cold environment where you’re not sweating in bed, you’re wearing pajamas and you’ve had a shower before going to bed, it’s closer to every couple of weeks.

‘The average is every two weeks,’ Dr Karl said. 

He highlighted a British study that found some four per cent of people wash their sheets once a year.

Meanwhile, men who are in relationships wash their sheets once a month, while those who are single only do it every six weeks.

While some were grateful for Dr Karl sharing the information about washing cycles, others said once a fortnight simply isn’t enough.

‘Once a week… that nice fresh smell and feeling, if I was rich and didn’t care, I’d have fresh sheets every day,’ one commenter wrote.

‘Weekly. My husband has very oily skin so must be done weekly at a minimum!’ another added.

A third wrote: ‘Every Friday is a bedsheet changing day. In my country this is normal’.

While a fourth added ‘Once a week, it’s my Monday schedule. Strip the bed and let mattress get some sun/air for a few hours’. 

In a TikTok video, the 76-year-old explained that on average, you should be washing your bed sheets every two weeks, but you might need to be doing it more often if you live in a hot place or sweat often during the day (Dr Karl pictured)

According to the Sleep Foundation, you should be washing your sheets once a week if you sleep on your mattress every night.

This is because we spend 49 to 60 plus hours sleeping in our beds at night, which is ‘ample time to build up dirt, sweat, oil, and other gunk on our sheets and bedding’.

If you have pets, and particularly if you let them sleep in your bed, a wash every 3-4 days is recommended. 

If you experience allergies or asthma, it may be worth it to try cleaning your bedding more frequently to see if your symptoms improve.

The Sleep Foundation also said it’s also recommended to wash sheets more often in the warm summer months, as you will likely get more sweat on your bedding.