Is it better to sleep on a hard or soft mattress? Well, it depends on your preference whether you like a soft or hard mattress. The soft mattress is after all soft and cushions your body. The hard mattress, as the name suggests, gives your body a stiff surface to sleep on. Usually, the results are also in the same vein. When you sleep on a soft mattress, your body sinks into its soft cushion and when you wake up your body tends to be loose and sagging. The joints and muscles are in a state of relaxation. It will take a while to train them for an active daily life.