Soft Mattresses (Firmness)

A soft mattress compresses more readily under body weight than a medium or firm option, allowing the surface to conform more closely around the contours of the body. That closer conforming is the main functional benefit, and it is most relevant for side sleepers, who experience concentrated pressure at the shoulder and hip where those points make contact with the mattress. A softer surface allows those areas to sink in rather than be pushed against, which reduces pressure and helps keep the spine in a more neutral alignment when lying on your side.

Soft mattresses also suit lighter sleepers more naturally than heavier ones. Body weight determines how deeply you compress a mattress during sleep, so a lighter person will not sink as far into a soft mattress as a heavier person will. For a lighter sleeper, a soft mattress may feel appropriately cushioned and supportive. For a heavier sleeper, the same mattress may compress too deeply, allowing the hips or shoulders to sink through the comfort layers into the support core, which can cause the spine to fall out of alignment and lead to discomfort over time.

Construction affects how a soft mattress performs significantly. A memory foam mattress at the soft end of the range will give a slow, enveloping response that moulds closely around the body and holds that shape while you sleep. This is the construction most associated with a genuinely soft feel. A pocket sprung mattress described as soft will have a faster response and a more lifted feel compared to foam, because the springs push back as they compress. Hybrid mattresses at the softer end combine springs for support and breathability with foam comfort layers above, offering a surface that feels softer than a standard pocket sprung without the full body-enveloping quality of a pure memory foam design. For those who sleep hot, a hybrid soft mattress is worth prioritising over a pure foam option, as the spring base improves airflow through the mattress considerably.

One consideration that is easy to overlook with soft mattresses is edge support. A softer mattress compresses more at the edges when weight is applied there, which can make getting in and out of bed feel less stable and can reduce the usable sleeping area if you sleep near the edge. Better-constructed soft mattresses include a firmer edge support system around the perimeter of the spring unit, which maintains the shape of the mattress and keeps the sleeping surface consistent across its full width.