What is pillow loft and why does it matter?

Loft is simply the height or thickness of a pillow, and it is the single most important factor for neck comfort. The goal is to keep your head and spine in a straight line while you sleep. Too high pushes the neck up; too low lets it drop. Side sleepers need high loft, back sleepers medium, and stomach sleepers low. The broader your shoulders, the more loft a side sleeper needs.