Choosing a Mattress for Side Sleepers

On your side, two narrow points — the shoulder and the hip — carry your whole body weight. A mattress for a side sleeper has to let those two points sink in while holding the waist up. Everything else is detail.

How to tell your mattress is too firm

These are the signals, in the order people usually notice them:

• A sore or dead arm on the side you slept on.
• Waking up and rolling onto your back within a few minutes, every night.
• Aching at the hip joint rather than in the muscle.
• A gap you can slide a hand into under your waist when you lie on your side.

That last one is the test. Lie on your side on the bed and have someone look along your spine. It should run roughly straight, following the line it has when you stand. If the hips and shoulders are held up and the waist dips, the mattress is too firm. If the hips sink below the line, it is too soft.

The firmness range

Most side sleepers land between 4 and 6 out of 10. Adjust for weight: under about 60 kg, aim at 4; over about 95 kg, aim at 6 or 7, because you will compress more of the comfort layer than the rating assumes.

Every product page here carries the firmness number, and the medium range is one click away.

Depth of the comfort layer matters more than the total depth

A 38 cm mattress with 3 cm of comfort layer will feel firmer to a side sleeper than a 27 cm mattress with 6 cm. The shoulder needs somewhere to go, and the only part it can go into is the comfort layer. Look at the layer breakdown on the product page, not the headline depth.

As a rough guide, a side sleeper wants at least 4 cm of memory foam or 5 cm of latex above the support core.

Memory foam or latex or micro springs

Memory foam

The most contour per centimetre. It softens where your body heat concentrates — the shoulder and hip — which is exactly where you want give. The cost is heat and slow response. Four centimetres over a spring unit is the sensible middle: Supreme Memory.

Latex

Contours less, recovers instantly, runs cooler. If you turn from one side to the other several times a night, latex makes that easier. Copper Latex 7-Zone is zoned along its length — softer under the shoulder, firmer under the hip — which is a genuine advantage for side sleeping.

Micro springs

Small springs above the main unit, under the comfort layer. They follow the body more closely than foam of the same depth because each one moves independently. MicroPocket Memory is built this way.

The pillow is half the problem

Side sleepers need more pillow height than back sleepers, because the gap between the head and the mattress is the width of your shoulder. Too flat and the neck bends downward all night. A firm, high pillow that holds its loft is the right answer — latex holds height better than any fibre fill. See the pillows.

Getting the mattress right and the pillow wrong produces almost exactly the same neck ache as getting both wrong.

Common questions

Should I put a knee pillow between my legs?

It stops the upper leg dragging the pelvis forward and rotating the lower spine. Many side sleepers find it makes more difference than they expect, and it costs nothing to try with a spare pillow.

Is a soft mattress bad for my back?

Not if it supports you. Soft and unsupportive is bad. Soft with a firm core under it is exactly what side sleeping wants — see firm vs medium vs soft.

How long until my shoulder stops aching on a new mattress?

Give it three to four weeks. If it is worse at week four than week one, the mattress is wrong, and that is what the 100-night trial is for.