What Is Memory Foam?

What is memory foam?

Memory foam is the popular term for visco-elastic polyurethane foam. It was originally developed by NASA as a means to relieve the enormous pressure of the g-forces experienced by astronauts on shuttle take-offs. While it wasn't subsequently used for this purpose, its potential benefits as a pressure-relieving sleeping surface were recognised.

The term 'memory foam' arises from the foam's reaction to pressure. Memory foam absorbs pressure, moulding to the contours of the object placed on it. When, for example, a hand is pressed into a memory foam mattress, it will 'remember' the impression, retaining an indentation for some time as it slowly returns to its original shape.

This makes it an ideal sleeping surface because the memory foam will mould to the body in such a way that weight, and therefore pressure, is evenly distributed. As you lie on a memory foam mattress the foam seems to melt away around you as it adapts to your weight and position.

The benefits of memory foam

Most materials will 'push back' when pressure is applied. The structure of memory foam, however, allows it to absorb pressure by conforming to the contours of your body. By moulding to the exact shape of your body, memory foam allows your body weight to be evenly distributed across the entire sleeping surface, rather than being focused on particular contact points where pressure can build up. This can help to prevent the back or neck pain many people experience as a result of their sleeping positions. It also reduces the disturbance to your sleep caused by tossing and turning.

Of course, this doesn't mean the same sleeping position has to be maintained. Memory foam adapts quickly to your movements during the night. The visco-elastic foam is softened as it comes into contact with body heat allowing it to adapt to your body shape as you move and change position. This temperature-sensitivity means that as you settle in, the memory foam is fine-tuned to your body shape.

A good sleeping posture is therefore maintained, regardless of your preferred sleeping position, with body weight evenly distributed across the surface of the mattress.

The differences between foam and memory foam

Ordinary polyurethane foam does not have the pressure relieving properties of memory foam. While ordinary foam will indent when an object is placed on it, it will immediately retain its original shape when that object is removed. This is because the material is pushing upward, trying to return to its natural shape.

On the other hand, memory foam will absorb downward forces by allowing itself to be moulded. This greatly reduces the reacting upward force on any object placed on it. This difference can be easily demonstrated by dropping an object on each material. The object will bounce on ordinary foam because as the foam springs back it applies an upward force. On memory foam there will be little or no bounce because the downward force is absorbed.

High quality memory foam can provide significant advantages over traditional mattresses, particularly for anyone who suffers from back or neck pain in their existing bed. Because of its moulding properties and the area of contact when lying on it, it can require some adjustment for those accustomed to traditional spring mattress types, and may not be suitable for everyone. It is up to you to decide if a memory foam mattress is for you, but with such significant potential benefits it is something everyone should consider.