My wife and I are in the market for a new mattress and thinking about moving to memory foam after having innerspring mattresses. We’ve like the feel of memory foam mattresses we’ve tried, but I’m curious to know more about how they adapt to a body over the course of a night. I’ve read that they soften with heat and pressure, which enables the foam to compress. We’ve experienced a feeling of slowly “sinking into” the mattress, which seems most pronounced for 20-30 seconds before they stabilize. After continuing to lay on the mattress for 5 or so minutes in a position before switching, it doesn’t appear to be conforming/changing much more, at least not noticeably. But I’m curious about longer term time spent on a memory foam mattress. Does one typically continue to sink significantly noticeable amounts over the span of the night or does the bulk of the settling in typically occur in the first few minutes of laying in a position?
Hi BSON,
Memory foam will soften in response to heat, temperature, and the length of time it is continuously compressed. The changes are more rapid over the course of the first few minutes but there can be smaller changes over time as well so with thicker layers of memory foam there is a greater risk that you may be in good alignment when you first go to sleep at night but may be out of alignment when you wake up in the morning. How much this may affect any specific person on a specific memory foam mattress will depend on the design of the mattress, the thickness of the memory foam layers, and on the specific formulation of the memory foam(s) in the mattress.
When you are testing memory foam mattresses I would tend to spend a little extra time with your testing compared to the normal 15 minutes I would suggest for other types of mattresses to give the memory foam a little more time to warm up.
There is more about the pros and cons of memory foam in general in this article.
There are also hundreds of different formulations of memory foam on the market that have different firmness ranges and different properties (such as slower or faster response times, more or less breathable, more or less temperature sensitive etc) depending on the chemical formulation of the memory foam. There is more about the different properties that can be formulated into of different types of memory foam in post #9 here and in post #8 here.
Phoenix