The fundamental purpose of a mattress is to keep you straight. If your back–from your shoulders to your hips–are not straight while you’re asleep you will wake up with back pains. This fundamental function has been forgotten within the last 20 years. Mattresses today are made for appearance: the bigger and fatter they appear the easier it is to sell. The truth is, people slept much healthier 30 years ago when mattresses were thinner and firmer and reversible: what it lacked in comfort is more than made up for in support. Mattress can be comfortable and supportive at the same time. The very surface of the mattress can provide comfort, but, the core of the mattress has to provide support. The level of support is different for everyone. Our bodies are all different; we all come in various shapes and sizes, so the level of support in one mattress might not be the same from one person to the next.