Memory foam, was initially developed under a NASA contract in the 1970s that set out to improve seat cushioning and crash protection for airline pilots and passengers. Since then memory foam is now being used for a variety of different things such as mattresses, bed pillows, cushions and even shoe insole.
Memory foam is completely heat sensitive, which means the material reacts to your natural body heat. This allow the pillow to naturally cradle the neck & shoulders. This helps to ensure that no one part of your neck has direct pressure, which can cause pain. As the memory foam cradles the neck, it evenly spreads pressure and helps you keep your neck and spine in a comfortable position. The memory foam gently conforms to the shape of your body and its natural hollows in your neck and shoulders helping to send you off into a deep sleep. A high-density memory foam pillow will have better compression ratings over the life of the product. Where as a lower-density one will have slightly shorter life due to the compression that takes place after repeated use.