Hi DahliaM,
The overall physiology of stress is probably outside the scope of a mattress forum (and can be a whole field of study in itself) and I’m certainly not a doctor that is qualified to speak in any detail about it but in general it can cause or aggravate more sleeping symptoms than almost anything else. Emotional or psychological stress is almost always accompanied by physical stress and muscle tension which in turn can lead to many symptoms on a mattress (and many other non mattress symptoms as well). Stress can restrict blood flow in the skin and surface tissues to allow the blood flow to better support the deeper muscles and tissues which in turn could lead to pain, soreness, or stiffness from reduced blood flow or restricted movement and can also cause muscle soreness from muscles that remain tense and “ready for action” and aren’t allowed to relax, rest, and recover or joint tissues that aren’t able to rehydrate and regain their natural flexibility.
People who suffer from elevated stress of any type (physical, psychological, or emotional) often have sleeping issues of many types. While stress is one of those “catch all” descriptions that can cover just about anything, it can (and usually does) lead to muscle tension and rigidity and lack of flexibility which in turn can lead to soreness and excess pressure because the body is “holding” itself in a less flexible and more rigid position that can change the pressure distribution throughout the body. It can also lead to the inability to relax enough to reach the deeper more healing levels of sleep.
I think the article says it as well as I could and there is a post I linked here in the tutorial post from one of the members who is an athlete and personal trainer which I also thought was very informative.
I also think that one of the benefits of wool or other soft fluffy fibers or feathers is that it can provide a “feel” softness (see post #15 here about the different types of softness) which can be comforting and relaxing emotionally which in turn can help people relax even if it doesn’t directly improve pressure relief. A better microclimate in terms of temperature and moisture can also help the autonomic nervous system to slow down as well. They also provide a more “relaxed” sleeping surface where shear forces are less (the type of forces that are in the same direction as the mattress surface and can “pull” on the skin or surface tissues) which can also help the body and surface tissues to relax especially for those who may be more sensitive.
Phoenix