The Sleep Council – funded by the trade association for British bed manufacturers – is proudly proclaiming this month as ‘sleepanuary’ and they are also raising awareness of ‘the seven year hitch’. This recommends you ‘start to think about replacing your bed after seven years’. Why? According to the Sleep Council, after seven years your bed ‘may look okay but it may not be giving you the support of comfort you need for a healthy, refreshing night’s sleep’. Georgina decided to dig into the science behind this.
"I asked for evidence behind the claim that we should be buying new beds every seven years, and I was sent quite a bit of information. These included:
• A study conducted by The Furniture Industry Research Association (FIRA) which doesn’t seem to be available online.
• An E-release from the Sleep Council based on a survey by “those who suffer from bad backs and the experts who treat them”.
• A review on dust mites in mattresses.
• A study in French on Actimuscle.
• A published and peer reviewed paper about back pain relating to sleep quality.
• And finally a study conducted on sleep quality on new versus old beds.
That’s quite a lot of information to sift through. For me, the two take home points here are that much of the information supplied doesn’t seem to be peer reviewed, and that not much of it is related to the specific claim that seven is somehow a magic number when it comes to replacing your bed.
The final study on quality of sleep in new versus old beds sounded the most promising, but the Sleep Council were unable to send me a copy. The study was conducted by Dr Chris Idzikowski so I decided to get in touch with him. Dr Idzikowski said “[t]he study wasn't reported further as it had taken two years to get 28 subjects out of the planned 100. The subjects were a convenience sample recruited via bed shops. The claims relied on a post hoc analysis of why the subjects had bought new beds and hinged on whether the beds were bought as the old bed was uncomfortable -versus- replacement.”
Dr Idzikowski also clarified that his study was on beds, not mattresses (I would like to mention this point since the Sleep Council website flits between talking about beds and mattresses in reference to ‘the seven year hitch’). Dr Idzikowski said that there is some objective evidence that buying a new bed will do something. It’s worth pointing out here that the people in the study were choosing to buy a new bed, presumably because they weren’t happy with their old one. Dr Idzikowski was pretty clear, too, that “my study on its own doesn’t support the suggestion that people will have a better night's sleep if they bought a new mattress every seven years, only that a new mattress may confer benefit”."
Is comfort the only reason for changing your mattress? There seems to be evidence that the older a mattress is, the higher the build-up of house dust-mite allergens. Having spoken to Asthma UK and Professor Deborah Jarvis, a professor in public health, there are some caveats with using this argument to encourage people to regularly replace their mattresses.
Professor Jarvis indicated that this build-up of allergens is perhaps more relevant to those who are sensitised to house dust-mites and have asthma, and therefore an imposed time limit on replacing mattresses is presumably only relevant to a proportion of the population. Professor Jarvis suggested that there is only limited evidence that even for those who are sensitive, replacing your mattress would help, a point echoed by Asthma UK. Although there’s little evidence that it helps, some people and some doctors believe it works for them and their patients.
So what does the evidence tell us? Sleeping on an uncomfortable bed isn’t as comfortable as sleeping on a comfortable bed. Does your bed suddenly become uncomfortable or ‘not fit for purpose’ after seven years? There is no evidence to support a ‘one size fits all’ figure of seven years. It’s probably best to just buy a new bed when your old one is no good anymore – and that’s down to you.
Image by Masahiko OHKUBO - (CC BY 2.0)