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Firm or soft mattress - which one should You choose?

25 czerwca 2025
firm or soft mattress, types of mattress firmness, mattresses
Selecting the right mattress for sleeping is one of the most important decisions when it comes to our daily comfort and health. However, the purchase decision is often based on misconceptions, such as the belief that heavier individuals should sleep on firm mattresses, while lighter people should choose very soft ones. In reality, knowledge from the fields of biomechanics and sleep physiology shows that what truly matters is matching the mattress firmness to the physiological alignment of the body, not its weight. This importance is also emphasized in modern scientific literature.

In recent years, public awareness of sleep ergonomics has increased. Consumers have begun to deeply appreciate the importance of regeneration and deep sleep, including how mattresses impact everyday functioning. More and more people now understand that good sleep is not just about comfort, but also a long-term investment in spinal health. This influences metabolism, mood, and cognitive abilities - in short, the overall quality of life.

Reason and knowledge over myths

Let’s remember that contrary to a common myth, mattress firmness should not be selected based on a person’s weight. The human body distributes proportionally on a mattress, so someone with a higher body mass also has a larger surface area. That means they have more contact points compared to someone lighter. As a result, pressure on a single point is not necessarily greater than in a lighter person.

A mattress that is too firm does not allow for contouring immersion of the body, which leads to pressure in the hip and shoulder areas. This results in muscle tension that should be avoided. On the other hand, a mattress that is too soft can cause sinking, leading to unnatural spine curvature. Proper mattress dynamics help maintain the natural spinal curves and evenly distribute body weight.

That’s why a well-designed medium-firm mattress, which provides stable support while allowing for gentle contouring of key areas like shoulders and hips, is the most functional solution currently available. This is confirmed by research in ergonomics and physiotherapy, which shows a correlation between comfort and medium firmness.

The shamelessly perfect Osaka Air mattress is built around this very idea. It combines high-resilience HR foams with a layer of memory foam, ensuring the right balance between comfort and support, without the sinking effect. This approach is based solely on human physiology, not on harmful stereotypes.

Medium mattress firmness is the optimal choice

For many years, a firm mattress was considered a symbol of healthy sleep, especially in marketing messages. Today, however, we know that a hard mattress is not actually good for the spine. Hard mattresses can disrupt blood circulation and cause discomfort, particularly in the joints and muscles. Their users may wake up with stiffness or pain, which indicates that the body was not able to relax. This is also confirmed by scientific studies conducted by a team of researchers.

On the other hand, very soft mattresses also fail to provide sufficient support for the spine, especially in the lumbar region, which people rarely take proper care of. This can cause the spine to sag and bend excessively, which over time leads to back pain, reduced recovery quality, and also frequent position changes during the night that interrupt deep sleep cycles.

The key is matching flexibility to the natural needs of the body. Open-cell foams, like those used in ONSEN® mattresses, allow intelligent adaptation to the user’s anatomy. They also enhance air circulation, reducing overheating and sweating – the typical problems of poor-quality mattresses.

When it comes to mattresses, extreme softness and excessive hardness are two harmful extremes. They represent a false answer to the body’s sleep needs. Only by choosing a well-designed medium-firm mattress do you opt for a solution that aligns with scientific knowledge.

Disadvantages of mattresses that are too hard or too soft

A medium-firm mattress meets the diverse needs of different body types as well as sleeping positions. Properly selected high-resilience foams, such as HR30100 and HR35120 in the Osaka Air mattress, provide durability, elasticity, and resistance to deformation – all key features. The thermoelastic foam V50075 in the second layer of the mattress, on the other hand, ensures anatomical support, since its placement eliminates the suction effect.

As scientific research shows, properly chosen mattresses improve sleep quality, especially for people with back or shoulder pain, but also for those with sleep disorders. Medium firmness is perceived as the most comfortable by the majority of people, and this is entirely independent of body weight, as weight does not play a role here.

Choosing the right bedroom mattress is not about the subjective feeling of comfort during a quick visit to a store. In the 21st century, there is no longer room for buying a mattress in physical stores where proper testing is impossible. Not to mention mattress returns, which are usually not allowed there. This is a strategic decision concerning health and the quality of recovery, which directly impacts daily comfort. That is why it is worth trusting the logic of proportional body distribution rather than outdated myths.

ONSEN® not only understands this but also educates its pack so that they understand it too. Medium firmness is not a compromise but a functional optimum – a solution based on knowledge.

Biomechanics of sleep and mattress firmness

Choosing a mattress is not a matter of personal whim, but of health. A medium-firm mattress like the Osaka Air mattress from ONSEN® is the most well-founded choice for a wide range of users, regardless of body type. It supports proper spinal alignment, ensures thermal comfort, aids regeneration, and reduces pressure points.

The myths claiming that a heavier person should sleep on a board-hard mattress, and a lighter person on one as soft as cotton, have no scientific basis. What matters more is body structure—its surface area and how weight is distributed. That’s why it’s worth trusting science over stereotypes. Only then can we build healthy, restorative sleep and challenge the status quo together.

We also encourage you to explore other articles on the best sleep and health blog, as well as the Encyclopedia of Healthy Sleep prepared by the ONSEN® team of specialists. For those who care about spine health, we recommend a set of spine exercises prepared by our physiotherapist.

FAQ: Firm or soft mattress?

Is a soft or firm mattress better?

Neither extremely soft nor very firm mattresses are ideal. A good mattress conforms to the body without a sinking effect while providing stable support for the spine. Too soft, and the body sinks without support; too firm, and pressure and muscle tension occur. A medium-firm mattress offers the best balance of comfort and ergonomics. The soft vs. firm divide is too simplistic - quality, elasticity, and body alignment matter more.

Is it better to sleep on a firm or soft mattress?

Neither extreme is good. A mattress that?s too firm prevents proper body contouring, leading to pressure on hips and shoulders. A mattress that?s too soft lets the body sag and curves the spine unnaturally. A well-designed medium-firm mattress is the best solution?it supports and adapts to the body?s anatomy.

Do doctors still recommend firm mattresses?

No. That?s an outdated belief. In the past, it was thought that a rigid body position was always beneficial. Today, we know that such stiffness can do more harm than good. Similarly, many fractures are no longer routinely immobilized with a cast. Firm mattresses are an old-fashioned choice that?s falling out of favor.

Why do firm or soft mattresses cause back pain?

A too-firm mattress applies pressure to sensitive points, disrupting circulation and causing muscle tension?leading to stiffness and pain in the morning. A too-soft mattress fails to support the spine, letting the lumbar area sag, which over time causes discomfort and sleep disruption.

Why do I have a stiff back even though I sleep on a firm mattress?

Firm mattresses prevent the body from contouring naturally. Without proper relief for hips and shoulders, pressure builds up and causes stiffness and pain. Such mattresses interfere with muscle relaxation and blood flow, leading to stiffness after sleep.

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ONSEN® is a Polish manufacturer of mattresses, orthopedic pillows, bedding, and ergonomic furniture.