Investigating the Impact of Long-Term Use on Mattress Firmness and Sleep Quality: Preliminary Results
Study by Zoran Vlaović, Nino Klarić and Danijela Domljan (Faculty of Forestry and Wood Technology, University of Zagreb, Croatia)
Lab Test of 2 Mattresses · Applied Sciences (Vol. 14, Issue 21, Article 10016) · DOI: 10.3390/app142110016
Key Takeaway
In a Lab Wear Test, Two Mattresses Kept Most of Their Firmness
What was tested: Researchers at the University of Zagreb ran a machine wear test on 2 mattresses, one with a polyurethane foam core and one with a pocket spring core. They used a modified version of the European EN 1957 test method (Vlaović et al., 2024).
What the numbers showed: The foam mattress compressed at first and then held steady, ending with a total height loss of 3.79 mm. The pocket spring mattress softened slightly, with hardness falling from 5.86 to 5.21 N/mm and a total height loss of 2.86 mm.
What this means for you: Both mattresses kept most of their firmness in this test. But only 2 mattresses were tested, by machine, so the study cannot tell you how long any mattress you buy will last.
Key Numbers
How the Study Was Done
This short communication, published in Applied Sciences in 2024, tested 2 mattresses of different build: one with a polyurethane foam core and one with a pocket spring core. A machine wore each mattress down in a mechanical durability test, using a modified method based on the European standard EN 1957 (Vlaović et al., 2024).
During the test, the team measured hardness (how much force it takes to press the mattress down, in newtons per millimetre), a firmness rating, and height loss. The title mentions sleep quality, but no one slept on the mattresses. The authors looked at sleep quality only indirectly, through the changes in the mattresses.
What the Study Compared
Polyurethane Foam Core
Compressed at first, then held steady. Hardness settled between 7.53 and 9.03 N/mm and ended at 8.60 N/mm. Height loss 3.79 mm.
Pocket Spring Core
Softened slightly: hardness fell from 5.86 to 5.21 N/mm. Firmness rating stayed between 7.3 and 7.1. Height loss 2.86 mm.
What the Study Found
For the foam mattress, hardness dropped at first and then settled between 7.53 and 9.03 N/mm, ending at 8.60 N/mm. Its firmness rating settled at 4.3, moving only between 4.0 and 4.6, and it lost 3.79 mm of height in total (Vlaović et al., 2024).
For the pocket spring mattress, hardness generally fell as the test went on, from 5.86 to 5.21 N/mm. Its firmness rating stayed between 7.3 and 7.1, and it lost only 2.86 mm of height.
The authors say both samples kept their firmness and support in this test, and that a mattress's firmness can still change with use. They call for more research with a larger number of mattresses. The abstract and publisher record we could read do not state who funded the work.
How to Apply This Study When Choosing a Mattress
What it tells you: Mattresses can change a little with use, but this test found small changes in 2 samples.
The study does not rank foam types or densities, and it does not predict the life of any brand. Read the warranty terms on sagging, and use the return window to judge how the bed feels on you.
Study Scope and Limitations
Only 2 mattresses were tested, both by machine and not by people sleeping on them. The paper calls its results preliminary. It did not test memory foam, latex or hybrid designs, or any named brand.
Primary Citation
Vlaović, Z., Klarić, N., & Domljan, D. (2024). Investigating the impact of long-term use on mattress firmness and sleep quality: Preliminary results. Applied Sciences, 14(21), 10016. https://doi.org/10.3390/app142110016