If you sleep on your back and keep waking up stiff, the culprit is usually loft, the height of the pillow, not the pillow itself. A back sleeper wants a medium loft that fills the space under the neck and keeps the head level. The more useful answer is that the right height is measured to your own frame, and you can set it yourself instead of guessing off a chart.
A back sleeper wants the head level, not lifted.
When you lie on your back there is a gap between the back of your head and the mattress, and your neck curves through it. The pillow fills that gap so the curve is supported and your spine stays in a neutral line. Get it right and the muscles in your neck switch off for the night. Get it wrong and they hold tension for hours.
Too high and too low both strain the neck.
Too much loft pushes your head up and forward, so your chin drops toward your chest and the back of your neck stretches all night. Too little lets your head tip backward, which shortens the muscles behind the neck and drops the jaw open. Both leave you stiff in the morning, and a pillow that is too tall can crowd your airway, which is one reason it can make snoring worse.
How to check your own loft.
Lie down the way you normally sleep and look from the side, in a mirror or a photo. Your forehead and chin should sit about level, and your nose should point at the ceiling. The pillow should meet the curve of your neck, not just prop up the back of your skull. When it is right, the pillow feels like it is barely there.
A fixed medium is a guess at an average neck.
Every pillow on the shelf says medium, but necks are not average. A broad-shouldered person on their back has a deeper gap to fill than a smaller-framed person, so the same pillow is right for one and wrong for the other. And it drifts over time, because a sealed pillow compresses, so the loft you bought is not the loft you have a year later.
You set the loft by taking fill out.
Every Circadian pillow ships overstuffed, with more fill than most people want, and you open the side zipper and remove fill until your head sits level. You tune the height to your own frame and your own mattress, a handful at a time, until the pillow disappears under your head. Take out too much and you put some back. The fill lives in your hands, ready to add or remove.
Which fill a back sleeper should reach for.
Buckwheat is the one for firm, held support. The hulls flex to the shape of your neck and then lock against each other, so the support does not sink as the night goes on, and air moving between the hulls keeps it cool. If you want that support with a gentler surface, the buckwool hybrid pairs a firm buckwheat side with a soft organic wool side. For a plusher medium you set by removing batting, organic wool holds its height and springs back each morning, and organic cotton holds a steady, even shape for years. Kapok is the down-like option, soft and airy, and a quick daily fluff keeps its loft where you want it.
Side, back, and stomach each want a different height.
Loft is a conversation between your position and the gap you are filling. A side sleeper has the widest gap, from the mattress up to the ear across the whole shoulder, so side sleepers need the most height. A stomach sleeper wants the least, close to flat. A back sleeper lands in the middle. An adjustable pillow matters because you can set the loft for the position you spend the most time in, and if you shift for good, you adjust it instead of buying another pillow.
The loft you set is the loft you keep.
A sealed pillow flattens, and you slide below the height you need without noticing until your neck starts to complain. With an adjustable natural fill you do the opposite. When it settles you add a little fill back or redistribute what is there, and the height you set on night one holds for years. So if you are waking up with a stiff neck right now, check loft before anything else. The fix is usually a handful of fill in or out, and it takes about a minute.
Every Circadian pillow is handmade in our New Jersey workshop and ships overstuffed so you set your own loft. If you are deciding which fill to start with, our fill guide walks through cotton, wool, buckwheat, latex, kapok, and the Buckwool Hybrid.
