While all mattresses have some form of underlying support layer, it’s the upper layers that determine how soft or firm it feels. Choosing a comfortable firmness level for your sleep needs comes down to more than just personal preference, though. Different sleep positions and different body types require different levels of support in order to achieve healthy sleep.
Mattress firmness levels are rated on a scale of 1 to 10; one is the softest and 10 the firmest. A mattress of the right firmness will evenly distribute your weight, cushion your pressure points, and support your spine in a neutral position. Two popular mattress firmness levels are medium and firm, and here we’ll discuss the pros and cons of each to help you decide which will work best for you.
On the mattress firmness scale, an 8 is considered firm with extra firm mattresses available in the 9 to 10 range. A firm mattress evenly distributes body weight and promotes neutral spine alignment while sleeping on your back. It can even help to improve posture and reduce back pain. For those with mobility issues, a firm mattress is often easier to get in and out of because it contours less than softer mattresses so you won’t get “stuck.”
Benefits for Back Sleepers
The best mattresses for back sleepers are firmer. They provide support for the lower back and distribute the sleeper’s weight evenly, preventing pain at pressure points. Your muscles and ligaments are also more likely to relax with your weight spread out, which promotes healing.
Benefits for Stomach Sleepers
It’s important for the hips to be aligned while sleeping, otherwise the natural curvature of the spine can be exaggerated. Mattresses for stomach sleepers are also firm to support their hips and prevent any undue pressure on the back or neck.
Benefits for Heavy Sleepers
The best mattresses for heavy individuals are medium-firm to firm. Those weighing 250 pounds or more—should experience minimal sinking while they sleep. Sinking can make you feel stuck, making it difficult to change position or get out of bed. By keeping the torso properly lifted and aligned with the shoulders, a firm mattress will also allow for better lung expansion and circulation.
Benefits for Hot Sleepers
The contouring of a soft mattress can cause increased body heat because of how much of the mattress is in contact with your body. A firm mattress, on the other hand, can reduce overheating with less contact and better airflow, both of which make them cooler mattresses.
Cons of Firm Mattresses
Side sleepers will find that firm mattresses don’t provide enough contouring for their pressure points. When lying on your side, your hips and shoulders are the heaviest parts of your body and require more cushioning to prevent aches and pain from occurring. Side sleepers also need more contouring than a firm mattress can provide in order to prevent their spine from curving while lying in this position.
A firm mattress may seem like a good idea for those with arthritis, since it promotes a neutral spine position, but it can actually make pain worse by failing to properly cradle joints and pressure points. In most cases, medium mattresses offer the best of both worlds.
A medium mattress is considered a 5 on the firmness scale. It’s right in the middle of soft and firm, thus having a good balance between the two: it cradles and helps to promote neutral spine alignment. This makes it good for most body types. Those who are lighter sleepers, weighing 130 pounds and under, still get enough compression for contouring. And for medium sleepers, in the range of 130 pounds to 230 pounds, a medium mattress provides enough firmness to prevent sinking.
Benefits for Side Sleepers
Medium mattresses make the best beds for side sleepers because they contour in order to cradle pressure points, and are also firm enough to help the spine remain neutrally aligned. If the spine is forced to curve, back muscles tense, resulting in pain or soreness. While sleeping on your side, pressure builds at the points that bear the most weight in that position—the hips and shoulders. The contouring of a medium mattress cushions those areas to help prevent tension and pain.
Benefits for Combination Sleepers
Combination sleepers are those that change sleeping positions throughout the night. Medium mattresses make the best beds for combination sleepers because they provide them the support needed for a neutral spine position while back sleeping. Then, when they roll over onto their sides, it will contour to relieve their pressure points.
Benefits for Co-Sleepers
Since medium mattresses work well for a variety of sleep positions and body types, they are often the best option for couples. They can cushion one person sleeping on their side as well as support another who prefers to sleep on their back.
Cons of Medium Mattresses
While medium mattresses are a versatile, popular firmness choice, they may cause problems in certain situations. Heavier sleepers may sink into a medium mattress too much, causing their spine to come out of alignment, and those with chronic back pain might not get enough support to stop their lower back from collapsing. Instead, sleepers in these situations should opt for a more supportive medium-firm level mattress.
Is there a way to change the firmness level of my mattress?
If you’re not ready to purchase a new mattress yet, or have gone past your trial period, you can try adding a topper to adjust the firmness level. A mattress topper will make your bed softer while a medium or firm memory foam topper will make your mattress firmer and add extra support. Toppers are relatively inexpensive and available for most mattress sizes.
How long does it take to find out if a mattress is the right firmness for me?
Mattresses have a breaking in period of about 30 days. If you’re worried about buying the wrong mattress, you’ll be glad to know that many retailers now offer sleep trials lasting a month or more.
Are firm mattresses more expensive than medium ones?
Generally speaking, firm and medium mattresses will cost about the same amount for the same bed size. Although, some mattress companies do use additional layers of foam in the comfort layers in order to achieve more firmness. In such cases, the added foam can translate into added cost.
Are innerspring mattresses firmer than memory foam mattresses?
Traditional innerspring mattresses have very thin comfort layers, which tends to make them firmer. A memory foam beds or hybrid mattress, however, can be just as firm, or even firmer, than an innerspring. You can typically find your preferred firmness level on any type of mattress.
Is a firm or medium mattress better for someone with arthritis?
For those suffering from arthritis, important considerations include the promotion of a neutral spine position as well as pressure point relief. While firm beds will promote spine alignment for back sleepers, the lack of contouring may exacerbate arthritic joint pain. More likely, a medium or medium-firm mattress will be the best bed for arthritis.
Getting your best sleep means finding the best mattress for your body type, sleep position, and any chronic health issues you may experience. A mattress with a comfortable firmness level that cradles your pressure points and keeps your spine aligned is more likely to help you fall asleep faster and enjoy a better quality of sleep. After all, you’ll feel much more rested when you’re not tossing and turning throughout the night or waking up in pain.
Chris was a psychiatrist and neurologist with board certification in sleep medicine Clinical Associate Professor at the University of California. For over 10 years, he served and helped patients at Stanford Health Care-Stanford Hospital with their sleeping disorders.
After suffered from sleep disorders for years, Chris has been passionate about sleep health ever since. He wants to help others sleep better and wanted to make the world of sleep easy to understand for everyday people.