Choosing a Mattress for Back Pain

The long-standing advice to buy the firmest mattress you can tolerate is not supported by the research. Controlled trials comparing firmness levels in people with chronic lower back pain have generally favoured medium-firm over firm, and a very firm surface can make things worse by forcing the spine out of neutral alignment and concentrating pressure on the shoulders and hips.

The mechanism is simple. Your spine has natural curves. A surface that is too soft lets the hips sink and the lower back sag; a surface that is too hard holds the hips up and leaves a gap under the lumbar curve, so the muscles work all night to hold you together. A medium-firm mattress is the range that most often keeps the spine level while still yielding at the shoulder and hip.

Be careful with the word "orthopaedic". In the UK it is not a regulated or certified term. Any manufacturer can print it. It usually signals a firmer build, which — per the above — is not automatically the right build for back pain. Judge the mattress on its firmness and construction, not the label.

Firmness is felt, not measured. The same mattress feels softer to a heavier person and firmer to a lighter one, so the starting point shifts:

You are	Start at	Reason
A side sleeper with back pain	Medium	The shoulder and hip need somewhere to go, or the spine bends sideways
A back sleeper with back pain	Medium-firm	Supports the lumbar curve without letting the hips drop
A front sleeper with back pain	Firm	Stops the hips sinking and over-arching the lower back
Over roughly 16 stone	One level firmer than above	More load compresses the comfort layers further
Under roughly 9 stone	One level softer than above	Not enough load to engage a firmer build's pressure relief

If two people share the bed and disagree, the wider sizes matter more than the firmness argument: a King or Super King reduces the movement transfer that wakes a painful back in the first place.

• Pocket sprung — independent springs contour to the body zone by zone rather than as one sheet, which is what produces support and pressure relief at the same time. The most reliable starting point for back pain.
• Memory foam — outstanding at pressure relief and at stopping a partner's movement from waking you. The trade-off is heat and a slow response, which some people with stiffness dislike because turning over takes effort.
• Open coil — a single connected spring unit. Fine for a guest room, but it moves as one piece and offers the least targeted support. Not the first choice if your back is the reason you are shopping.

Depth matters less than people expect. A deeper mattress is not automatically more supportive — the comfort layers and the spring system do the work, not the total height.

We would rather not sell you a mattress that will not help. Consider these first:

• Your base. A sagging divan or a slatted frame with wide or broken slats will undermine any mattress on top of it. Replacing the mattress alone can be money wasted.
• Age. Most mattresses lose meaningful support somewhere around seven to eight years. If yours has a visible dip, the mattress genuinely is the problem.
• Your pillow. Neck alignment and lower-back pain are connected more often than people realise, and a pillow costs a fraction of a mattress.
• New, severe or radiating pain — particularly pain that travels down a leg, or that wakes you every night — is a matter for a GP or physiotherapist, not a mattress purchase. Nothing on this page is medical advice.