Quick answer: yes, memory foam works for heavy sleepers, but only at the right density. Standard-density memory foam (roughly 30-32 kg/m3) can sag under sustained heavier load, which is where the "heavy people need coil or latex" advice comes from. That does not apply to high-density open-cell foam: the Mr Mattress Ultra 200 uses 60-density open-cell memory foam over a 65-density Chip foam foundation core, specifically engineered to resist compression at higher body weights, and is rated to 200kg per sleeper.
Where the myth comes from
It is common advice, including from some SA retailers, that heavy sleepers should avoid memory foam entirely and choose a coil or latex mattress instead. The advice exists because it is grounded in something real: standard, budget-grade memory foam is usually made at a lower density (around 30-32 kg/m3) to keep costs down, and that density genuinely does compress and sag faster under sustained heavier weight. If your only experience of memory foam is a low-density budget mattress that developed a dip, the advice to avoid the category makes intuitive sense.
Myth vs verdict, one belief at a time
Myth: memory foam always sags under heavy sleepers. Verdict: low-density memory foam does. Density, not the foam-versus-coil choice, is the variable that determines whether a mattress holds up.
Myth: a coil or spring core is automatically more durable for a heavy sleeper than foam. Verdict: not automatically, it depends on the coil gauge and the quality of the support structure just as much as foam depends on density. A poorly specified coil unit can fail just as a low-density foam layer can; a well-specified one, like our own Hybrid Foam Mattress with its 2.4mm oven-tempered Bonnell coil, independently tested to EN 1957 at a 140kg rolling load with 96% height retention, is a genuinely strong option too. The point is not that foam beats coil or coil beats foam; it's that the underlying spec, not the category label, decides durability.
Myth: a higher weight rating always means better quality. Verdict: only if a density number backs it up. Several SA sellers publish 150-200kg weight claims without publishing any foam density behind the number, which makes the claim unverifiable. We publish the Ultra 200's density (60, open-cell, SABS certified) specifically so this claim can be checked rather than taken on trust.
What actually makes memory foam hold up under heavier weight
Two things: the density of the comfort layer itself, and what sits beneath it. The Ultra 200 pairs 60-density open-cell memory foam (roughly double a typical budget mattress's density) with a 65-density Chip foam foundation core, a bonded, structural foam whose job is purely to resist compression at the centre of the mattress rather than provide pressure relief. The softer comfort layers handle contouring; the dense core stops the whole structure from bottoming out. That two-part design, not the fact that it's memory foam at all, is what earns the 200kg rating. Full layer-by-layer detail is on the Ultra 200 spec sheet.
Frequently asked questions
Is memory foam bad for heavy people?
Only at low density. Standard-density memory foam (around 30-32 kg/m3) can sag under sustained heavier weight. High-density open-cell memory foam, like the Ultra 200's 60-density core, is engineered specifically to resist that.
Should a heavy sleeper choose coil, latex, or memory foam?
Whichever is built to the right specification for their weight, with a published number behind the claim, a foam density figure for foam mattresses, or a coil gauge and independent durability test result for coil mattresses. The category label alone does not determine durability.
What density memory foam is recommended for a heavy sleeper?
There is no single universal number, but the Ultra 200 uses 60-density open-cell foam over a 65-density structural core specifically for sleepers up to 200kg. Its mid-tier Revive (50 kg/m3) is rated to 140kg.
Does the Ultra 200 use the same memory foam as budget mattresses, just more of it?
No. It is a different, higher density (60 vs the roughly 30-32 kg/m3 typical of budget memory foam), plus a separate dense structural core beneath it, not simply a thicker layer of the same foam.
Related: Ultra 200 product page · Full spec sheet and proof · Best mattress for heavy people in South Africa (200kg rated)
Reviewed by Andries Taljaard, Founder of Mr Mattress.