Memory foam softens when it comes into contact with your body heat, molds to your unique contours, and distributes your weight equally with excellence at absorbing the force of an impact.

Memory foam also returns relatively slowly to its original shape when force is removedon average, around3-5 seconds. During this recovery period, energy from the impact is absorbed and dissipated. This time lag, a phenomenon known as hysteresis, also helps cushion sleepers, because it removes some of the pressure (or, impact energy) produced by the prone body.

its viscosity decreases with temperature. This means that it becomes less stiff and more flexible the hotter it gets. This is the reason why memory foam mattresses feel softer or more pliable after youve been lying on them for a time, since your body heat increases the temperature of the sleep surface.