Of men aged 18 to 25 who were single, more than half changed their sheets about four times a year. (Kirill Kudryavtsev/AFP/Getty)

Watch out ladies, the man of your dreams may have the bed of your nightmares.

The average single man washes his sheets just four times per year, according to a survey by U.K. mattress company Ergoflex.

The survey asked Britons about their bed sheet hygiene and found a few stomach-churning results.

Among single men aged 18 to 25, 55 per cent changed their sheets every 3.1 months. Of that grubby group, 49 per cent figured that was an acceptable frequency, and another 19 per cent didn't care.

Not surprisingly, 17 per cent of those men also admitted that their soiled sheets had "put off" potential romantic partners.

"Romantic ambitions aside, we were more alarmed by the potential health risks that unhygienic bed sheets could cause, considering in particular two unwelcome night-time companions — dust mites and bed bugs," Ergoflex's Steven Willis wrote in a blog post.

The cleanest demographic were women aged 35 to 50, with 60 per cent of those changing their linens weekly.

Couples were generally clean as well, changing the sheets every 2.3 weeks, although the men could work a little harder; among the couples surveyed — 81 per cent of women said they carry the sheet-changing responsibilities.