Choosing a mattress seems simple until you get to the store and see terms like "medium," "firm," or "soft." Which one is right for you? The answer depends on two key factors: your body weight and your habitual sleeping position. Understanding how these two elements interact will save you nights of discomfort and unnecessary back pain.
What is firmness and why does it matter?
Firmness is not the same as support. Support refers to how well the mattress keeps your spine aligned, while firmness describes the surface feel when you lie down. A mattress can be firm on the surface but have good internal support, or be soft and let you sink in without properly supporting your body.
The firmness scale generally goes from 1 to 10, where 1 is extremely soft and 10 is as hard as a board. For most people, the ideal range is between 4 and 7.
Firmness according to your sleeping position
If you sleep on your back, your spine needs more uniform support. Medium-firm mattresses (5-6) usually work best because they allow the lumbar area to maintain its natural curve without sinking.
Those who sleep on their side put more pressure on their hips and shoulders. For this group, a softer firmness (4-5) is ideal, as it allows those areas to sink in slightly while the spine remains aligned.
Sleeping on your stomach creates tension in the neck and lower back. If this is your usual position, a firmer mattress (6-7) prevents your hips from sinking too much and arching your back in a harmful way.
Many people change positions during the night. For them, a medium-firm mattress (5-6) offers the most versatile balance.
Body weight and the right choice
Your weight directly influences how you perceive firmness. A light person (less than 65 kg) might find a medium-firm mattress too firm, while a person over 90 kg might find it soft and insufficient.
People under 65 kg usually prefer softer options (3-5) so that the body is properly supported without the surface feeling resistant.
For the 65 to 90 kg range, most medium-firm mattresses (5-6) work very well. This is the range for which standard options are designed.
Above 90 kg, it is better to opt for medium-high to firm firmness (6-8) to prevent the mattress from degrading quickly and losing support over time.
Most common combinations and our recommendations
A light person who sleeps on their side should look for a soft to medium-soft mattress (3-4). This is the combination that most frequently leads to discomfort when ignored.
A person of average weight who sleeps on their back will find their sweet spot in medium firmness (5-6), the best-selling and most versatile standard.
Someone who is overweight and sleeps in any position should prioritize a firm mattress with good lumbar support, such as pocket spring models or high-density foam ones.
Remember that no description replaces a real-life test. At Sommistore, we offer 100 trial nights precisely so you can verify on your own body whether you made the right choice.
What if I sleep with a partner?
If you and your partner have very different weights or sleeping positions, consider a pocket spring mattress, where each spring acts independently. This way, each area of the mattress responds to the specific weight of whoever is resting there, without one person's movement affecting the other.
Alternatively, there are mattresses with zoned firmness, designed exactly for this situation.
The key is that no decision should be permanent without testing it first. Your body is the best indicator.
Leave a comment
This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.