What kind of mattresses were used?
For the first 28 days of the study, the subjects slept on their own mattresses – all commercially made innerspring constructions of varying types and all more than 5 years old. For the second 28 days, subjects slept on new mattresses and foundations built specifically for the research using generic components to create a medium-firm sleep surface—not too hard, not too soft. The mattresses were constructed of a foam-encased Bonnell spring unit, densified fiber pad, super-soft foam and a damask cover, supported by a semi-flex foundation. The new beds were the same size the subjects had been sleeping on and were placed in their own bedrooms, where they used their own linens, blankets and pillows. Study methodology A sample of healthy subjects (30 women and 29 men) with no clinical history of disturbed sleep participated in the study. The subjects recorded perceived low back discomfort, spine stiffness, sleep quality, sleep comfort, and sleep efficiency (defined as the proportion of time i
