Sleep Number ComfortNext Lux Smart Bed: Redefining support

Photo: Julia Forbes

Like any Sleep Number smart bed, the ComfortNext Lux offers 100 firmness levels, and the level you select is your “Sleep Number,” or the firmness you prefer to sleep at. I usually lean toward lumbar support and firmer weight distribution, which was previously in the 40 to 50 range. Then, a new recommendation appeared in the app — my firmness level was in the mid-70s, but switching to softer can improve my sleep score, which Sleep Number calls its “SleepIQ Score” and shows up in its app. I decided to lower it to a softer hardness level of 35.

The SleepIQ score summarizes metrics of your night’s sleep, including heart rate variability, breathing rate, and time spent in each sleep stage. This data is compiled into a score that summarizes your sleep quality. The app’s score was always lower than what the Apple Watch SE could track. However, as dogs jump in and out of bed, sensors track that movement and take it into account as well. However, my Apple Watch showed a six-day streak of high sleep scores from the 80s to the 90s. Since my body is always getting used to new beds with a revolving door of mattresses to test, this is very rare for me. Previously, when testing other smart beds or standard mattress types like memory foam or hybrid, I would achieve this kind of good sleep with medium-firm mattresses or real firm mattresses, never soft ones.

What was clear after two weeks of testing was that even on the firmest 100 setting of all, the ComfortNext Lux still felt only moderately firm. They start out firm and get softer, but the truth is that ComfortNext Lux premium foam layers will always make whatever level you choose softer. If you’re looking for a really firm mattress — like one of our favorite firm options, the Plank Firm Luxe — the ComfortNext Lux doesn’t even remotely play in the same league. This isn’t shocking, since almost all of the smart beds I’ve tried lack the firmness you find in coil-based designs.

I got your back

If you regularly suffer from back pain or have serious spinal conditions like scoliosis, I wouldn’t recommend this smart bed for you. My husband is part of this club, and according to him, ComfortNext Lux is doable for a few days. After a short while, he needs to return to a firmer mattress to get the support his spine needs. To that end, ComfortNext Lux lumbar support is not where it should be for full-time stomach sleepers or heavier sleepers who need lift around their midsections. Some adjustable bases have lumbar support bars that pop out of the base, which would be a helpful treatment here. Unfortunately, this feature is not available on Sleep Numbers bases at the moment, and I would not recommend pairing this smart bed with an adjustable base from another brand.

If it’s not a case of back pain, you might be wondering who the ComfortNext Lux is best suited for. short? Side sleepers. As a side sleeper, this mattress provides the level of cushioning I often crave for my pressure points, with a satisfying amount of sink that leaves my joints feeling cushiony. You really feel isolated, and not in a claustrophobic way. For couples who sleep on the side or back, the foam protrusion in the ComfortNext Lux also helped prevent movement from rocking the bed. However, it is a little difficult to move between sleeping positions because you are working on a softer surface while rolling over.