The short answer: Medium-firm suits most people with chronic low back pain; that is what the best-known trial found. Firm suits stomach sleepers, heavier back sleepers, and people who reliably sleep better on hard surfaces. Side sleepers rarely do well on firm. Examples: Leesa Original Hybrid (6–8/10) and Brooklyn Bedding Plank Firm (firm/extra-firm).
Leesa Original Hybrid (11 in)
Leesa's foam feel on top of pocketed coils, rated a little firmer than the all-foam Original.
Open the Amazon listing
Brooklyn Bedding Plank Firm (10 in foam)
A deliberately hard, two-sided foam bed for people who have been sleeping on the floor to get relief.
Open the Amazon listing| Leesa Original Hybrid (11 in) | Brooklyn Bedding Plank Firm (10 in foam) | |
|---|---|---|
| Maker's firmness | 6–8 of 10 | Extra firm (10) / firm on the flip side |
| Build | Hybrid, 11 in, 789 coils | All-foam, 10 in, flippable |
| Best for | Back and combination sleepers | Stomach sleepers, heavier back sleepers |
| Side sleeping | Workable | Hard on shoulders and hips |
| Trial | 120 nights | 365 nights |
| Warranty | Listed as 14 years | 10 years |
What the trials found
In 2003, Kovacs and colleagues randomly assigned 313 adults with chronic low back pain to sleep on either a firm or a medium-firm mattress for 90 days, without telling them which they had. The medium-firm group reported less pain lying in bed and on getting up, and less disability. Reviews since then have mostly agreed: medium-firm tends to do better than both soft and very firm for people with ongoing, non-specific low back pain.
That is a population result. It does not say firm is bad for everyone; it says the old "hard bed for a bad back" rule was too simple.
When firm is the right call
- You sleep on your stomach.
- You weigh more than about 230 lb and sleep on your back.
- Your current bed lets your hips sink, and you feel better on the floor or a hard hotel bed.
When medium-firm is
- You sleep on your side, or move between side and back.
- You are light to average weight.
- Your pain is worse in the morning on a hard surface.
Two examples
Leesa Original Hybrid: the maker prints 6–8 out of 10, which is medium-firm in plain terms, with coils for support.
Brooklyn Bedding Plank Firm: the firmest bed we found, with a slightly softer flip side if the extra-firm side is too much.
Unsure? Put a firm topper on your current bed for a few weeks. It answers the question for far less money. Toppers for back pain.
Still choosing? Reader questions
Is a firm or medium-firm mattress better for back pain?
For most people with chronic low back pain, medium-firm. Firm suits stomach sleepers and some heavier sleepers.
Can a mattress be too firm for back pain?
Yes. Sore shoulders and hips on waking, or a gap under the lower back when lying flat, are signs.
Neutral Spine is not a medical provider. A mattress can make sleep more comfortable; it does not treat a spinal condition. Pain that follows an injury, spreads down a leg, or comes with numbness, weakness or fever needs a doctor first. Full disclaimer.