length from the outer edge of the shoulder to the armpit..??

Hi guys
I read that a reasonable measure for how thick a comfort layer should be (for example 4 inches etc.) is by measuring the length from the outer edge of the shoulder to the armpit… meaning mines about 5 inches or so and hence should I be testing beds which have atleast 5 inches of comfort layer of whatever combination of medium or soft latex ?
(i was going for a custom-made latex bed…I was thinking 8 -10 inches total thickness as i just 5’6" and 130 Lbs. …i know its talalay but i do not know the ILD yet, i need to call Jim at OK mattress).

Hi dr.cherlan,

This is just a concept that is meant to explain why side sleepers need thicker layers than back sleepers. Like any generic information though it’s only a rough guideline and isn’t specific to any particular person.

The idea is that a larger distance from the outer edge of the shoulder to the torso means that the shoulders need to sink in to the upper layers of the mattress more than people who have a smaller distance before the torso takes up the weight. How far you sink in will depend on how all the layers of the mattress interact not just the surface layers because every layer of a mattress affects every other layer to different degrees. The surface area at the point of contact of the shoulders and the upper body weight will also make a difference because pressure is a function of force per per surface area and there is also a very wide range of sleeping positions that may affect the contact area of the shoulders. People who sleep more on the “point” of the shoulder (pure side sleeping) will have less surface area than those who sleep in a more “forward leaning” position when they are on their side for example.

In other words … I would treat these as concepts and general guidelines but I wouldn’t use any specs to “design” a “perfect” mattress based on “theory at a distance” unless you have personal experience with a specific design or something very close to it as a reference point. There are so many variables in body type and physiology, sleeping positions, preferences, and sensitivity to pressure and alignment that only your own body and personal experience is the only way to know which design works best for you. Everything else is just a guideline than can help with your initial choice or “starting point” but may not be the “ending point” that works best for you.